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Sawangsri K, Makowka S, Bencharit S, Kim H. Effect of sintering cycle on the strength and translucency of multilayered zirconia. J Prosthodont 2024. [PMID: 39331036 DOI: 10.1111/jopr.13956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 09/08/2024] [Indexed: 09/28/2024] Open
Abstract
PURPOSE A newly introduced sintering protocol promises to offer higher translucency while not significantly compromising the flexural strength of the material. However, the effect of the novel sintering protocol has not been thoroughly validated. The purpose of this study was to measure and compare the effect of two sintering protocols on the translucency and flexural strength of two multilayered zirconia materials. MATERIALS AND METHODS Two types of multilayered zirconia materials (ZirCAD Prime and Prime esthetic) were selected. Presintered disk specimens were obtained from Translucent, Gradient, and Dentin layers (n = 20). The disks were allocated to 2 groups: standard sintering protocol (peak temperature 1500°C) and high translucency sintering protocol (peak temperature 1600°C). After the sintering process, 10 specimens from each group were randomly selected. The optical values (L*, a*, b*) were measured and used to assess translucency using the relative translucency parameter (RTP00) and translucency differences (ΔRTP00). Then, all 20 specimens were tested for biaxial flexural strength. The outcomes were analyzed. The analysis of variance is used to analyze any significant effects on translucency and flexural strength. Then, any significant difference in the translucency and flexural strength between all pairs of materials was analyzed using Bonferroni-corrected Student's t-test (α = 0.05). RESULTS The high translucency sintering protocol significantly decreased biaxial strength in the Prime translucent and dentine layer, Prime esthetic translucent, and gradient layer. RTP00 was significantly reduced in the Prime gradient and Prime esthetic gradient layer when sintered with a high translucency protocol. The lowest ΔRTP00 was observed in the Prime dentine layer, while the highest ΔRTP00 was observed in the Prime esthetic dentin layer. CONCLUSIONS High translucency protocol significantly lowers the biaxial flexural strength of both multilayered materials, but the alteration in translucency is within clinically acceptable thresholds (TAT00 = 2.62).
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Affiliation(s)
- Kedith Sawangsri
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Steven Makowka
- Material testing facility, School of Dental Medicine, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Sompop Bencharit
- Department of Reconstructive and Rehabilitation Sciences, James B. Edwards College of Dental Medicine, The Medical University of South Carolina, Charleston, South Carolina, USA
| | - Hyeongil Kim
- Department of Restorative Dentistry, School of Dental Medicine, The State University of New York at Buffalo, Buffalo, New York, USA
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Ghanem R, Adel A, Al-Zordk W. Effect of simulated intraoral adjustment on the color and translucency of gradient multilayered monolithic zirconia. J Prosthet Dent 2024:S0022-3913(24)00597-3. [PMID: 39332992 DOI: 10.1016/j.prosdent.2024.08.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 08/29/2024] [Accepted: 08/30/2024] [Indexed: 09/29/2024]
Abstract
STATEMENT OF PROBLEM The use of multilayered monolithic zirconia ceramics is becoming popular because it simplifies the production of esthetic restorations. The effect of clinical adjustment on the optical properties of these ceramics, especially strength-gradient zirconia, remains unclear. PURPOSE The purpose of this in vitro study was to evaluate the color and translucency of gradient multilayered zirconia brands after grinding and polishing. MATERIAL AND METHODS Sixty 10×10×1-mm monolithic zirconia specimens were milled from 6 zirconia brands (Ceramill Zolid HT White, Ceramill Zolid HT Preshade, Ceramill Zolid FX Multicolor, VITA YZ XT Multicolor, IPS e.max ZirCAD Prime, and KATANA YML). The zirconia specimens were milled to include all layers of A2 preshaded multilayered zirconia blanks (A2 shade) except Ceramill Zolid HT White and Ceramill Zolid HT Preshade. Ceramill Zolid HT White specimens were milled from a white zirconia blank with subsequent shading. The color coordinates and the relative translucency parameter after glazing and after grinding and polishing were determined with a reflectance spectrophotometer, and the relative translucency parameter and contrast ratio were measured. The differences in color and translucency were calculated. The data were analyzed using 2-way ANOVA and 1-way ANOVA tests followed by the post hoc Tukey test (α=.05). RESULTS Statistically significant changes (P<.001) in the color coordinates measured before and after grinding and polishing were detected for each zirconia brand except for the KATANA YML that showed no significant difference (P=.686) in lightness. The highest color difference after grinding and polishing was detected in group KATANA YML. The 2-way ANOVA test showed a statistically significant interaction (P<.001) between the zirconia brand and the grinding and polishing regarding the relative translucency parameter. The zirconia brand had a significant impact on the relative translucency parameter before and after grinding and polishing (both P<.001). CONCLUSIONS Except for KATANA YML, the color change in multilayered zirconia after clinical adjustment with polishing was not beyond the clinically acceptable limit of the color difference. Although clinical adjustment with polishing reduced the translucency of gradient zirconia, the change in translucency was below the clinically detectable threshold value of the translucency difference.
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Affiliation(s)
- Reham Ghanem
- Graduate student, Department of Fixed Prosthodontics, Mansoura University, Mansoura, Egypt
| | - Ahmed Adel
- Lecturer, Department of Fixed Prosthodontics, Mansoura University, Mansoura, Egypt
| | - Walid Al-Zordk
- Assistant Professor, Department of Fixed Prosthodontics, Mansoura University, Mansoura, Egypt.
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Vardhaman S, Borba M, Kaizer MR, Kim DK, Zhang Y. Optical and Mechanical Properties of the Multi-Transition Zones of a Translucent Zirconia. J ESTHET RESTOR DENT 2024. [PMID: 39325338 DOI: 10.1111/jerd.13319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/30/2024] [Accepted: 09/06/2024] [Indexed: 09/27/2024]
Abstract
OBJECTIVE To characterize the composition, flexure resistance, and optical properties of a multilayer translucent zirconia in relation to its multi-transition zones. MATERIALS AND METHODS A multilayer zirconia (5Y/4Y) and a conventional 3 mol% yttria partially stabilized zirconia (3Y) were investigated. Bar-shaped specimens were obtained from the enamel and dentin layers, and the vertical cross-section of 5Y/4Y (N = 10). A four-point flexural (σf) test was performed using a universal testing machine (1.0 mm/min). Plate-shaped specimens (N = 6) were also produced from the enamel, transition 1, transition 2, and dentin layers. Translucency parameters (TPab and TP00) were determined using a dental spectrophotometer (N = 6). X-ray fluorescence and X-ray diffraction techniques were used to analyze elemental (N = 2) and phase compositions (N = 2), respectively. Data were analyzed using analysis of variance (ANOVA) and Tukey's test (α = 0.05). RESULTS The yttrium content and σf varied between layers of 5Y/4Y. 3Y had the highest σf, followed by dentin. Enamel and cross-section showed lower and statically similar σf. 3Y and dentin groups had similar but statistically lower TPab and TP00 than the enamel. CONCLUSIONS Different layers of multilayered zirconia have distinct compositions, which affect their mechanical and optical properties. The weak enamel layer compromises the mechanical properties of cross-sectional specimens. CLINICAL SIGNIFICANCE The development of novel cubic-containing multilayer zirconia ceramics to produce monolithic restorations brings new challenges to dental clinicians and laboratory technicians. The CAD/CAM design of multilayered 5Y/4Y restorations should consider the esthetic and mechanical requirements of each clinical case, as different properties are found in the different layers of these materials.
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Affiliation(s)
- Sonaj Vardhaman
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- College of Dental Medicine, Columbia University, New York, New York, USA
| | - Marcia Borba
- University of Manchester, Manchester, UK
- University of Passo Fundo, Passo Fundo, Brazil
| | - Marina R Kaizer
- Centre for Rural Dentistry and Oral Health, Charles Sturt University, Orange, New South Wales, Australia
- Post-Graduate Program in Dentistry, Universidade Positivo, Curitiba, Paraná, Brazil
| | - Do Kyung Kim
- Department of Materials Science and Engineering, KAIST, Daejeon, South Korea
| | - Yu Zhang
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Strazzi-Sahyon HB, Campos TMB, Dos Santos C, Piza MMT, Alves LMM, Benalcazar Jalkh EB, Bergamo ETP, Tebcherani SM, Witek L, Coelho PG, Yamaguchi S, Bonfante EA. Effect of calcination on minimally processed recycled zirconia powder derived from milling waste. Dent Mater 2024; 40:1477-1486. [PMID: 38944559 DOI: 10.1016/j.dental.2024.06.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 06/16/2024] [Accepted: 06/18/2024] [Indexed: 07/01/2024]
Abstract
OBJECTIVE To assess the influence of calcination process on the properties of minimally processed recycled 3Y-TZP, and to compare it with its commercial counterpart. METHODS Non-milled 3Y-TZP waste was collected, fragmented and ball-milled to a granulometric < 5 µm. Half of the recycled powder was calcined at 900 °C. Recycled 3Y-TZP disks were uniaxially pressed and sintered to create two recycled groups: 1) Calcined and 2) Non-calcined to be compared with a commercial CAD/CAM milled 3Y-TZP. The microstructure of experimental groups was assessed through density (n = 6), scanning electron microscopy (n = 3) and energy-dispersive X-ray spectroscopy (n = 3); and the crystalline content was evaluated through X-ray diffraction (XRD) (n = 3). Optical and mechanical properties were investigated through reflectance tests (n = 10), and Vickers hardness, fracture toughness (n = 5), and biaxial flexural strength tests (n = 16), respectively. Fractographic analysis was performed to identify fracture origin and crack propagation. Statistical analyses were performed through ANOVA followed by Tukey´s test, and by Weibull statistics. RESULTS Particle size distribution of recycled powder revealed an average diameter of ∼1.60 µm. The relative density of all experimental groups was > 98.15 % and XRD analysis exhibited a predominance of tetragonal-phase in both recycled groups, which were similar to the crystallographic pattern of the control group. Cross-section micrographs presented flaws on the non-calcined group, and a more homogeneous microstructure for the calcined and commercial groups. Commercial samples showed lower contrast-ratio and higher translucency-parameter than the recycled groups, where non-calcined presented higher translucency-parameter and lower contrast-ratio than its calcined counterpart. The commercial group presented higher fracture toughness and characteristic strength than the recycled groups. Moreover, the calcined group exhibited higher hardness, characteristic strength, and probability of survival at higher loads than the non-calcined group. Fractographic analysis depicted the presence of microstructural flaws in the non-calcined group, which may have acted as stress-raisers and led to failures at lower flexural strengths values. SIGNIFICANCE The calcination process improved the microstructure, optical, and mechanical properties of the recycled 3Y-TZP.
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Affiliation(s)
- H B Strazzi-Sahyon
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil.
| | - T M B Campos
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil; Department of Physics, Aeronautics Technological Institute, São José dos Campos, SP, Brazil
| | - C Dos Santos
- Faculty of Technology, University of Rio de Janeiro State (UERJ - FAT), Resende, RJ, Brazil
| | - M M T Piza
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
| | - L M M Alves
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
| | - E B Benalcazar Jalkh
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
| | - E T P Bergamo
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil; Biomaterials Division, New York University College of Dentistry, New York, NY, USA
| | - S M Tebcherani
- Department of Production Engineering, Federal University of Technology, Paraná, Ponta Grossa, PR, Brazil
| | - L Witek
- Biomaterials Division, New York University College of Dentistry, New York, NY, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, New York University, Brooklyn, NY, USA
| | - P G Coelho
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - S Yamaguchi
- Department of Dental Biomaterials, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - E A Bonfante
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
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de Oliveira Limirio JPJ, Gomes JMDL, Santiago-Junior JF, Nagay BE, Pesqueira AA, Assunção WG, Alves-Rezende MCR, Pellizzer EP. Influence of ceramic crown design (translucent monolithic zirconia vs. bilayered) of implant-supported single crowns after mechanical cycling. J ESTHET RESTOR DENT 2024; 36:1326-1336. [PMID: 38665052 DOI: 10.1111/jerd.13237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 03/20/2024] [Accepted: 04/03/2024] [Indexed: 08/11/2024]
Abstract
OBJECTIVES This study aimed to assess the influence of translucent monolithic versus bilayered crowns and whether the use of a CoCr base abutments affects the fatigue and fracture resistance of screwed implant-supported single crowns with external connections under mechanical cycling. MATERIALS AND METHODS Fifty specimens were divided into groups: (1) metal-ceramic (MC) crown, (2) veneered zirconia crown (Zr), (3) veneered zirconia crown with a CoCr base abutment (ZrB), (4) monolithic translucent zirconia crown (MZr), and (5) monolithic translucent zirconia crown with a CoCr base abutment (MZrB). Specimens underwent mechanical cycling (5 × 106 cycles; 150 N) evaluating fatigue resistance (number of failures) and those that failed were subsequently subjected to fractographic analyses (stereomicroscope and scanning electron microscope) to evaluate failure location and area, and maximum fracture load was also measured. RESULTS The failure-related survival rate (100%) and maximum fracture resistance of the MZrB were significantly higher than those of MC and Zr (50%; p < 0.05). There were no significant differences in the failure rate and fracture resistance when a CoCr base abutment was used or not in the translucent monolithic Zr groups (p > 0.05;MZrB vs. MZr). Failure location, with MC crowns' fractures, noted at the screw area (p = 0.043), while all-ceramic crowns were mostly in the cuspid and to failure area, the Zr group had the largest mean (15.55 ± 9.17 mm2) among the groups, significant difference only when compared with MC (1.62 ± 0.81 mm2) (p = 0.025). CONCLUSIONS Translucent monolithic zirconia crowns exhibited significantly higher fatigue and fracture resistance compared with conventional MC and bilayered crowns. CLINICAL SIGNIFICANCE The appropriate choice of material and manufacturing technique is crucial for predicting the higher clinical performance of single crowns. Enhanced mechanical resistance in terms of fatigue and fracture resistance can be achieved by replacing MC and bilayered restorations with computer-aided design and computer-aided manufacturing monolithic zirconia.
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Affiliation(s)
| | - Jéssica Marcela de Luna Gomes
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (UNESP), School of Dentistry, Araçatuba, São Paulo, Brazil
| | | | - Bruna Egumi Nagay
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo, Brazil
| | - Aldiéris Alves Pesqueira
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (UNESP), School of Dentistry, Araçatuba, São Paulo, Brazil
| | - Wirley Gonçalves Assunção
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (UNESP), School of Dentistry, Araçatuba, São Paulo, Brazil
| | | | - Eduardo Piza Pellizzer
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (UNESP), School of Dentistry, Araçatuba, São Paulo, Brazil
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Valian A, Ghasemi A, Rastbood E, Zandian A, Zanguei E. Exploring physical and mechanical properties of hydrothermally processed recycled non-sintered dental zirconia wastes. J Mech Behav Biomed Mater 2024; 160:106708. [PMID: 39288663 DOI: 10.1016/j.jmbbm.2024.106708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 08/21/2024] [Accepted: 08/24/2024] [Indexed: 09/19/2024]
Abstract
BACKGROUND AND AIM The present investigation explored the potential for recycling residual blocks obtained from the machining processes under hydrothermal conditions. Furthermore, the study examined the recycled samples' various physical and mechanical properties to assess their viability for further use. MATERIALS AND METHODS In this in vitro study, Aman Girbach blocks were collected, half of which underwent a hydrothermal process, while the other half did not. The blocks were then subjected to ball milling. Uniaxial and isostatic pressed blocks were prepared, and 10 samples were obtained from each type of recycled block. These samples were compared to a commercial material, and four groups were formed based on the powder type and pressing method used. The quality control analysis of the recycled samples included assessing particle size distribution, identifying crystalline phases, analyzing color differences, examining microstructure, and evaluating mechanical properties. Statistical tests such as normal distribution calculations (k-s test), one-way ANOVA, Brown-Forsythe, Tukey HSD, and Games-Howell tests were used to compare the four groups and perform pairwise comparisons. RESULTS The flexural strength and density of the control commercial group were significantly higher than the other experimental groups (P = 0.000). Linear shrinkage of recycled isostatic pressed experimental bodies was significantly lower than that of others (P = 0.000). Qualitative evaluation of microstructure and crystalline phase by FESEM and XRD showed no significant difference in grain size and crystalline phase between different groups. CONCLUSION The hydrothermal process is a promising way to recycle zirconia ceramic with lower energy consumption. Recycled waste demonstrates potential as a cost-effective and viable option for ceramic prostheses in situations with low to medium stress levels.
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Affiliation(s)
- Azam Valian
- Dental Research Center, Restorative Department, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Amir Ghasemi
- Dental Research Center, Restorative Department, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Ehsan Rastbood
- Dental Research Center, Prosthodontic Department, School of Dentistry, Birjand University of Medical Sciences, Birjand, Iran.
| | - Amin Zandian
- Dental Research Center, Restorative Department, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Elham Zanguei
- Dental Research Center, Restorative Department, School of Dentistry, Birjand University of Medical Sciences, Birjand, Iran.
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da Silva BCD, da Silva SEG, da Silva NR, de Moreira FGG, Souza KB, Zhang Y, de Souza ROA. Effect of different surface treatments and adhesive cementation on the surface topography and flexural strength of translucent and ultra-translucent monolithic zirconia. J Prosthodont 2024. [PMID: 39189693 DOI: 10.1111/jopr.13929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 07/28/2024] [Indexed: 08/28/2024] Open
Abstract
PURPOSE To evaluate the effect of different surface treatments and adhesive cementation on the miniflexural strength (MFS) of monolithic zirconia. MATERIALS AND METHODS Two-hundred and forty (240) sintered bars of translucent zirconia (ZT) and ultra-translucent zirconia (ZUT) were obtained (8 mm ×2 mm ×1 mm). The bars were divided into 16 groups (n = 15) according to the factors "Zirconia" (ZT and ZUT), "Cementation" (Cem) and "surface treatment" (Ctrl:Control, Al:Aluminum oxide/Al2O3 50 µm, Si:Silica/SiO2 coated alumina particles oxide 30 µm, Gl:Glazing+hydrofluoric acid). Half of the bars received an adhesive layer application, followed by application of resin cement and light curing. The surface roughness was measured in non-cemented groups. All the bars were subjected to the MFS test (1.0 mm/min; 100 kgf). Scanning electron microscopy was used for qualitative analyses. MFS data (MPa) and roughness (µm) were statistically evaluated by three-way and two-way ANOVA respectively and Tukey's test (5%). RESULTS The surface treatment and the interaction were significant for roughness. Glazing promoted less roughness compared to silicatization. Regarding MFS, only the zirconia and surface treatment factors were significant. For ZT, the sandblasted groups had an increase in MFS and glazing reduced it. There was no difference between the groups without cementation for the ZUT; however, ZUT.Si/Cem, and ZUT.Al/Cem obtained superior MFS among the cemented groups. CONCLUSIONS Sandblasting increases the flexural strength for ZT, while glaze application tends to reduce it. Applying resin cement increases the flexural strength of ZUT when associated with sandblasting. Sandblasting protocols promote greater surface roughness.
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Affiliation(s)
| | - Sarah Emille Gomes da Silva
- Department of Dentistry, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | - Nathália Ramos da Silva
- Department of Dentistry, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | | | - Karina Barbosa Souza
- Institute of Science and Technology, Paulista State University (UNESP), São José dos Campos, São Paulo, Brazil
| | - Yu Zhang
- Department of Preventive and Restorative, University of Pennsylvania, School of Dental Medicine, Philadelphia, USA
| | - Rodrigo Othávio Assunção de Souza
- Department of Dentistry, Adjunct Professor in Prosthodontics, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
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Fathi A, Natanzian Y, Ghorbani M, Mosharraf R. Evaluation of the Bonding Shear Strength between Enamel and Dentin Feldspathic Porcelain and Two Different Monolithic Zirconia with Low and High Translucency. Int J Dent 2024; 2024:5921637. [PMID: 39148645 PMCID: PMC11326879 DOI: 10.1155/2024/5921637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/25/2024] [Accepted: 07/17/2024] [Indexed: 08/17/2024] Open
Abstract
Introduction The utilization of ceramics in the field of dentistry has seen a significant rise owing to their esthetic appeal and excellent functional properties. The use of ceramics in the field of dentistry has witnessed a notable surge, driven by their appealing esthetics and exceptional functional attributes. Zirconia, distinguished by its exceptional mechanical strength, plays a pivotal role in the fabrication of posterior crowns and bridges. Among zirconia variants, monolithic zirconia stands out, where the entire restoration is crafted from zirconia material. In parallel, feldspathic porcelain, chosen for its remarkable resemblance to natural tooth enamel, represents another significant ceramic type. This study aims to evaluate the shear bond strength (SBS) between two types of monolithic zirconia with two types of feldspathic porcelain. Methods and Materials Forty-four monolithic zirconia veneered discs with feldspathic porcelain were subjected to SBS testing. The dimensions of the discs were 7 mm in diameter and 5 mm in height (3 mm of zirconia and 2 mm of porcelain). Subsequently, the specimens were subjected to a universal testing machine at a speed of 0.5 mm/min until failure occurred. The type of failure was examined using scanning electron microscopy. One-way analysis of variance (ANOVA), two-way ANOVA, Fisher's test, and multiple Tukey comparisons were used as statistical analyses. Results The highest SBS was achieved by the high-translucency monolithic zirconia with enamel porcelain group (18.81 ± 3.18 MPa) and the high-translucency monolithic zirconia with dentin porcelain group (17.89 ± 2.75 MPa), followed by the low-translucency monolithic zirconia with dentin porcelain group (15.04 ± 2.24 MPa) and the low-translucency monolithic zirconia with enamel porcelain group (14.33 ± 2.00 MPa), respectively. Additionally, the most common type of failure pattern observed was mixed, followed by adhesive failure. Conclusion The translucency of the porcelain did not significantly affect SBS, while the type of monolithic zirconia used had a significant impact. Furthermore, there was no discernible relationship between the four groups in terms of the distribution of failure patterns.
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Affiliation(s)
- Amirhossein Fathi
- Department of Prosthodontics Dental Materials Research Center Isfahan University of Medical Sciences, Isfahan, Iran
| | - Yeganeh Natanzian
- Dental Students' Research Committee School of Dentistry Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahsa Ghorbani
- School of Dentistry Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ramin Mosharraf
- Department of Prosthodontics Dental Materials Research Center Isfahan University of Medical Sciences, Isfahan, Iran
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Vohra M, Pandurangan KK, Shenoy A, Keskar V. A Comprehensive Review of the Surface and Chromatic Properties of Monolithic Zirconia: Evaluating the Impact of Polishing and Finishing Methods on Aesthetics and Performance. Cureus 2024; 16:e66029. [PMID: 39221297 PMCID: PMC11366407 DOI: 10.7759/cureus.66029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2024] [Accepted: 07/31/2024] [Indexed: 09/04/2024] Open
Abstract
Monolithic zirconia is widely used in dentistry due to its outstanding mechanical properties, biocompatibility, and aesthetic qualities. This review examines how different polishing and finishing methods impact the performance and appearance of monolithic zirconia restorations. Derived from zirconium, zirconia is a robust ceramic that exists in monoclinic, tetragonal, and cubic forms, with properties that prevent crack propagation. Monolithic zirconia, preferred over porcelain-fused-to-metal (PFM) crowns, offers better aesthetics and avoids chipping. Various surface treatments, such as polishing and glazing, enhance zirconia's smoothness and wear characteristics. Polished zirconia is less abrasive to enamel than glazed zirconia, making it more suitable for opposing teeth. Research indicates that polished zirconia has a smoother surface and higher fracture resistance compared to other dental ceramics. Surface roughness, which is influenced by the treatment method, is crucial in minimizing wear on opposing teeth. Polished monolithic zirconia also shows high flexural strength, chipping resistance, and translucency. While both polishing and glazing reduce brightness, polishing better preserves translucency. The literature identifies polishing as the best post-processing method for enhancing zirconia's surface quality and mechanical properties without compromising its load-bearing capacity. In conclusion, polishing and finishing significantly improve the aesthetic and clinical performance of monolithic zirconia, confirming its effectiveness for durable and visually appealing dental restorations.
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Affiliation(s)
- Maaz Vohra
- Department of Prosthodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - Kiran Kumar Pandurangan
- Department of Prosthodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - Amrutha Shenoy
- Department of Prosthodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - Varun Keskar
- Department of Prosthodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
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Huang B, Chen M, Wang J, Zhang X. Advances in zirconia-based dental materials: Properties, classification, applications, and future prospects. J Dent 2024; 147:105111. [PMID: 38866229 DOI: 10.1016/j.jdent.2024.105111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/14/2024] Open
Abstract
OBJECTIVES Zirconia (ZrO2) ceramics are widely used in dental restorations due to their superior mechanical properties, durability, and ever-improving translucency. This review aims to explore the properties, classification, applications, and recent advancements of zirconia-based dental materials, highlighting their potential to revolutionize dental restoration techniques. STUDY SELECTION, DATA AND SOURCES The most recent literature available in scientific databases (PubMed and Web of Science) reporting advances of zirconia-based materials within the dental field is thoroughly examined and summarized, covering the major keywords "dental zirconia, classification, aesthetic, LTD, applications, manufacturing, surface treatments". CONCLUSIONS An exhaustive overview of the properties, classifications, and applications of dental zirconia was presented, alongside an exploration of future prospects and potential advances. This review highlighted the importance of addressing challenges such as low-temperature degradation resistance and optimizing the balance between mechanical strength and translucency. Also, innovative approaches to improve the performances of zirconia as dental material was discussed. CLINICAL SIGNIFICANCE This review provides a better understanding of zirconia-based dental biomaterials for dentists, helping them to make better choice when choosing a specific material to fabricate the restorations or to place the implant. Moreover, new generations of zirconia are still expected to make progress on key issues such as the long-term applications in dental materials while maintaining both damage resistance and aesthetic appeal, defining the directions for future research.
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Affiliation(s)
- Bo Huang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Mengbing Chen
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Jian Wang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China.
| | - Xin Zhang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China.
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Akhlaghi O, Camposilvan E, Garnier V, Goharibajestani Z, Khabbaz S, Ow-Yang C, Jorand Y, Gremillard L, Chevalier J. Conventional sintering of nano-crystalline Yttria-Stabilized Zirconia enables high-strength, highly translucent and opalescent dental ceramics. Dent Mater 2024; 40:1031-1040. [PMID: 38755041 DOI: 10.1016/j.dental.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/18/2024]
Abstract
Development of restorative materials capable of mimicking optical and mechanical performance of natural teeth is a quest in aesthetic density. Yttria-Stabilized Zirconia (YSZ) ceramics represent one of the most popular choices for dental restorations, owing to their biocompatibility, white colour, and the possibility to use CAD-CAM technologies. In particular, YSZ doped with 3 mol. % yttria (3YSZ) is popular because it presents high strength. Nonetheless, the limited light transmission of commercially available high strength 3YSZ does not meet the requirements of highly aesthetic cases. On the other side, YSZ presenting a larger portion of yttria are more translucent but exhibit modest strength. Here, we report on fabrication of dense zirconia nanostructures in bulk form via conventional pressure-less sintering at temperatures down to 1100-1200 °C, achieving highly translucent and strong 3YSZ with significant opalescent behaviour. Both Hall-Petch and inverse Hall-Petch relationship were observed in 3YSZ samples with average grain size in the range of 250 nm and 55 nm, demonstrating the importance of grain size control to enhance both optical and mechanical properties of zirconia ceramics, simultaneously. Maximum biaxial strength of 1980 ± 260 MPa, in-line light transmission of 38% in the visible spectrum and opalescence approaching that of enamel were obtained at optimum grain size of 80 ± 5 nm. The notable optical properties are linked to the miniaturization of the residual pores and refinement of grain size towards the nanoscale while the superior mechanical strength is justified by the activation of different energy dissipation processes at nano and macroscale.
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Affiliation(s)
- Omid Akhlaghi
- INSA Lyon, Universite Claude Bernard Lyon 1, CNRS, MATEIS, UMR5510, 69621 Villeurbanne, France
| | | | - Vincent Garnier
- INSA Lyon, Universite Claude Bernard Lyon 1, CNRS, MATEIS, UMR5510, 69621 Villeurbanne, France.
| | | | - Sirous Khabbaz
- Materials Science & Nano-Engineering Program, Sabanci University, Tuzla, Istanbul 34956, Turkey
| | - Cleva Ow-Yang
- Materials Science & Nano-Engineering Program, Sabanci University, Tuzla, Istanbul 34956, Turkey; Nanotechnology Research and Application Center (SUNUM), Sabanci University, Tuzla, Istanbul 34956, Turkey
| | - Yves Jorand
- INSA Lyon, Universite Claude Bernard Lyon 1, CNRS, MATEIS, UMR5510, 69621 Villeurbanne, France
| | - Laurent Gremillard
- INSA Lyon, Universite Claude Bernard Lyon 1, CNRS, MATEIS, UMR5510, 69621 Villeurbanne, France
| | - Jérôme Chevalier
- INSA Lyon, Universite Claude Bernard Lyon 1, CNRS, MATEIS, UMR5510, 69621 Villeurbanne, France
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Abdulrahman DM, Sherief DI, El-Korashy DI. Effect of different surface treatments on the bonding potential and physical and mechanical properties of ultratranslucent zirconia. J Prosthet Dent 2024; 132:219-228. [PMID: 35850873 DOI: 10.1016/j.prosdent.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022]
Abstract
STATEMENT OF PROBLEM Studies to determine a suitable surface treatment that improves bonding without compromising the strength or translucency of ultratranslucent zirconia are scarce. PURPOSE The purpose of this in vitro study was to evaluate the effect of different surface treatments on translucency, surface topography, phase transformation, biaxial flexural strength, bond strength, and durability. MATERIAL AND METHODS A total of 169 ultratranslucent zirconia disks were randomly divided into 4 groups according to the surface treatment applied: airborne-particle abrasion (APA) (n=46), tribochemical silica airborne-particle abrasion (TS) (n=46), nonthermal oxygen plasma (NTP) (n=46), and no treatment, control (C) (n=31). The translucency parameter (ΔTP00) was evaluated with a spectrophotometer (n=15), phase transformation was assessed with an X-ray diffractometer (n=5), surface topography was evaluated with a scanning electron microscope (SEM) (n=3), and biaxial flexural strength (BFS) was tested with a universal testing machine (n=15). For the microshear bond strength (μSBS) test, 40 composite resin specimens were attached to 8 disks and tested with a universal testing machine; 20 specimens were tested after 24 hours, and 20 specimens after hydrothermal aging in a thermocycler (TC). The data were analyzed with ANOVA followed by the Tukey post hoc test (α=.05). Weibull analysis was performed for the flexural strength and μSBS results. RESULTS Significant ΔTP00 differences were found among all groups and were highest for the APA group (7.33) and lowest for the NTP group (4.79). The NTP group had a significantly higher monoclinic weight fraction value (4.54%) than other groups. The NTP group had significantly higher BFS (581.31) than other groups, while the APA group showed significantly lower values than other groups (340.43). The APA group had significantly higher μSBS values after 24 hours (13.51 MPa) and after TC (13.68 MPa) than the other groups (P<.05). CONCLUSIONS Although APA and TS are effective techniques for improving resin-zirconia bonding, they result in significantly higher deterioration of translucency and strength. NTP significantly improved the BFS of zirconia; however, it showed lower bond strength values than other methods.
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Affiliation(s)
- Doaa M Abdulrahman
- Graduate student, Dental Biomaterials Department, Faculty of Dentistry, Ain-Shams University, Cairo, Egypt.
| | - Dalia I Sherief
- Professor of Dental Biomaterials, Biomaterials Department, Faculty of Dentistry, Ain-Shams University, Cairo, Egypt
| | - Dalia I El-Korashy
- Professor of Dental Biomaterials, Biomaterials Department, Faculty of Dentistry, Ain-Shams University, Cairo, Egypt
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Juntavee N, Juntavee A, Jaralpong C. Color Characteristics of High Yttrium Oxide-Doped Monochrome and Multilayer Partially Stabilized Zirconia upon Different Sintering Parameters. Eur J Dent 2024. [PMID: 38942053 DOI: 10.1055/s-0044-1787700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2024] Open
Abstract
OBJECTIVES Sintering influences the optical properties of zirconia. This study examined the effect of altering sintering temperature and time of monochrome (Mo) and multilayer (Mu) 5 mol% yttria-partially stabilized zirconia (5Y-PSZ) on color characteristics. MATERIALS AND METHODS Three hundred specimens (width × length × thickness = 10 × 20 × 2 mm) were prepared from Mo and Mu (with cervical [C], middle [M], and incisal [I] region) 5Y-PSZ and randomly sintered at decreasing (Td: 1,450°C), regular (Tr: 1,500°C), and increasing (TI: 1,550°C) sintering temperature, with extremely short (He: 10 minutes), ultrashort (Hu: 15 minutes), short (Hs: 30 minutes), and regular (Hr: 135 minutes) sintering time (n = 15/group). Color appearance (EW ), translucency parameter (TP), contrast ratio (CR), opalescence parameter (OP), and color appearance difference (∆E diff) were evaluated in the CIE L*a*b* system. Microstructures were evaluated by scanning electron microscope (SEM) and X-ray diffractometer (XRD). STATISTICAL ANALYSIS Analysis of variance (ANOVA) and Bonferroni comparisons were determined for significant differences (p < 0.05). RESULTS Significant differences in color parameters upon zirconia type, sintering temperature, and sintering time, and their interactions were indicated (p < 0.05). Increasing sintering temperature and extended sintered time resulted in larger grain, reduced tetragonal-to-monoclinic phase transformation, and significantly increased the TP and OP, but decreased the CR and ∆E diff (p < 0.05). Decreasing sintering temperature and time led to clinically unacceptable color appearance. CONCLUSION Mo was found to be more translucent than Mu. To achieve the most favorable optical properties, increasing sintering temperature and extending sintering time are recommended. Decreasing sintering temperature is not suggested. However, shortened sintering time is feasible, but it needs sintering with increasing sintering temperature to achieve a promising color appearance.
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Affiliation(s)
- Niwut Juntavee
- Department of Prosthodontics, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Apa Juntavee
- Department of Preventive Dentistry, Division of Pediatric Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Chutikarn Jaralpong
- Division of Biomaterials and Prosthodontics Research, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
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Rafiei A, Fakhrzadeh V, moslehifard E, Ranjbar G. In vitro effect of zirconia type on shear bond strength to feldspathic porcelain and wear of the opposing teeth. J Dent Res Dent Clin Dent Prospects 2024; 18:123-128. [PMID: 39071209 PMCID: PMC11282196 DOI: 10.34172/joddd.40755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/01/2024] [Indexed: 07/30/2024] Open
Abstract
Background Multilayer zirconia has more optical and aesthetic features than regular zirconia. Therefore, its mechanical properties should be compared with monochromatic zirconia. Among the mechanical characteristics that can be checked are the wear of the opposite tooth and the bond to the porcelain. This study assessed the effect of zirconia type (multilayer versus monochromatic) on the shear bond strength (SBS) to feldspathic porcelain and the wear of the opposing teeth. Methods The present in vitro study was conducted in two phases. In the first phase, 15 multilayer and 15 monochromatic zirconia blocks measuring 10×5×5 mm were designed, milled, sintered, veneered with porcelain, and underwent thermocycling. Their SBS was then measured in a universal testing machine. In the second phase, 15 multilayer and 15 monochromatic zirconia blocks were placed in a chewing simulator, and 30 sound premolars served as antagonistic teeth. The magnitude of wear of the buccal cusp of premolars was quantified from a 4-mm reference point after 100000 cycles. Data were analyzed by independent t test (α=0.05). Results The mean SBS of monochromatic zirconia to porcelain (24.49±3.58 MP) was slightly higher than that of multilayer zirconia (22.98±2.98 MP), but the difference was not significant (P>0.05). The mean wear of the opposing teeth was also slightly higher in the monochromatic group (284.1±66.53 µm) than in the multilayer group (263.2±58.69 µm), but this difference was not significant either (P>0.05). Conclusion Monochromatic and multilayer zirconia showed comparable SBS to feldspathic porcelain and caused comparable wear of the opposing teeth in vitro. Thus, multilayer zirconia may serve as an alternative to monochromatic zirconia.
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Affiliation(s)
- Amirhossein Rafiei
- Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Vahid Fakhrzadeh
- Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Elnaz moslehifard
- Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ghazal Ranjbar
- Student Research Committee, Faculty of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Abounassif FM, Alfaraj A, Gadah T, Yang CC, Chu TMG, Lin WS. Color stability of precolored and extrinsically colored monolithic multilayered polychromatic zirconia: Effects of surface finishing and aging. J Prosthodont 2024. [PMID: 38923252 DOI: 10.1111/jopr.13875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Accepted: 05/13/2024] [Indexed: 06/28/2024] Open
Abstract
PURPOSE To explore the impact of zirconia types, coloring methods, and surface finishing on the color stability of monolithic multilayered polychromatic zirconia after artificial aging, including thermocycling and simulated toothbrushing. MATERIALS AND METHODS Eighty square-shaped zirconia samples were divided into 2 types (M3Y-TZP and M6Y-PSZ), further categorized based on coloring methods (precolored and extrinsically colored) and surface finishing techniques (mechanical polishing or glazing). The color stability was assessed using the CIEDE2000 formula. Artificial aging was simulated via thermocycling and toothbrushing. All samples were analyzed with a spectrophotometer to determine the post-aging color changes (ΔE00). The ΔE00 were interpreted and classified using the 50:50% perceptibility threshold (PT) and the 50:50% acceptability threshold (AT). Comparisons between groups for ΔE00 differences were performed using three-way ANOVA, with pairwise comparisons facilitated by Fisher's protected least significant difference test, α = 0.05. RESULTS The study results indicated significant impacts of zirconia type, coloring method, and surface finishing on color stability. The M6Y groups experienced significantly greater color changes (6.61 ± 1.63) compared to the M3Y groups (3.40 ± 2.24), p < 0.0001. For both types of zirconia, extrinsically colored samples exhibited significantly higher ΔE00 when mechanically polished (p = 0.004). However, surface finishing had no significant effect on ΔE00 in precolored samples of either zirconia material (p = 1.000). The evaluation and categorization of ΔE00 variations indicated that nearly all color changes in the M6Y groups, regardless of being precolored, extrinsically colored, polished, or glazed, were deemed extremely unacceptable (Grade 1). In contrast, the M3Y groups showed more acceptable results, with the majority of color changes classified as moderately unacceptable (Grade 3). CONCLUSIONS The color stability of multilayered polychromatic zirconia is influenced by the type of material, extrinsic coloring, and the chosen surface treatment post-artificial aging. The translucent 6Y-PSZ exhibited lower color stability, especially with only mechanical polishing. For the fabrication of M3Y-TZP and 6Y-PSZ monolithic multilayered polychromatic zirconia restorations, extrinsic coloring should be paired with glazing to maintain color stability. Conversely, in the absence of extrinsic coloring, both glazing and mechanical polishing are effective in preserving color stability.
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Affiliation(s)
- Feras M Abounassif
- Dental Department, Al Imam Abdulrahman Bin Faisal Hospital, National Guard Health Affairs, Dammam, Saudi Arabia
| | - Amal Alfaraj
- Department of Prosthodontics, College of Dentistry, King Faisal University, Al Ahsa, Saudi Arabia
- Department of Prosthodontics, Indiana University School of Dentistry, Indianapolis, Indiana, USA
| | - Thuraya Gadah
- Department of Prosthodontics, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Chao-Chieh Yang
- Advanced Education Program in Prosthodontics, Department of Prosthodontics, Indiana University School of Dentistry, Indianapolis, Indiana, USA
| | - Tien-Min G Chu
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, Indiana, USA
| | - Wei-Shao Lin
- Department of Prosthodontics, Indiana University School of Dentistry, Indianapolis, Indiana, USA
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Chen L, Zhang X, Tian Z, Wang J. Effect of artificial aging on optical properties of ultra-translucent zirconia ceramics of different brands. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2024; 42:353-358. [PMID: 39049656 PMCID: PMC11190871 DOI: 10.7518/hxkq.2024.2023372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/05/2024] [Indexed: 07/27/2024]
Abstract
OBJECTIVES This work aimed to evaluate the effect of artificial aging on the translucency and color difference (ΔE) of ultra-translucent zirconia and provide a reference for clinical application. METHODS The discs of ultra-translucent zirconia from six brands (Wieland, 3M ESPE, Amann Girrbach, Kuraray Noritake, Upcera, and Besmile) were cut and sintered according to each manufacturer's product instructions; the experimental groups were named ZNT, LVP, AG, KAT, UPC, and BSM, respectively. IPS e.max Press was used as the control group (PLT). The specimens (n=6) were prepared with a diameter of 14 mm and a thickness of 1 mm. The specimens were subjected to artificial aging treatment according to the following conditions: in an autoclave at 134 ℃ at 0.2 MPa for 4, 8, and 12 h. According to the CIE1976Lab system, the CIE L*, a*, and b* values of the specimens before and after aging were measured by a co-lorimeter. The translucency parameter (TP) and ΔE were calculated. RESULTS The mean TP values of each group before aging inorder were PLT>KAT>AG>ZNT>BSM>UPC>LVP. We found no significant difference in translucency in all experimental groups after aging for 4 and 8 h compared with those before aging. After 12 h of aging, the TP values of the KAT and ZNT groups were not significantly different from those before aging, but the TP values of the AG, BSM, LVP, and UPC groups were significantly lower than those before aging (P<0.05). The TP value of the control group was significantly higher than that of the other experimental groups at different stages (P<0.05). ΔE=3.3 was considered the visible color difference, and ΔE was less than 3.3 in all groups after 4 h of aging. After aging for 8 h, ΔE of the UPC group was slightly higher than 3.3. ΔE of the BSM and UPC groups was greater than 3.3 after 12 h of aging. CONCLUSIONS The TP and ΔE of different brands of ultra-translucent zirconia may change after various aging times. The translucency of some zirconia showed a decreasing trend and the color difference showed an increasing trend with the aging time.
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Affiliation(s)
- Luona Chen
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Xin Zhang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Zhengyu Tian
- Dept. of Prosthodontics, Hospital of Stomatology, Fujian Medical University, Fuzhou 350002, China
| | - Jian Wang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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Cesar PF, Miranda RBDP, Santos KF, Scherrer SS, Zhang Y. Recent advances in dental zirconia: 15 years of material and processing evolution. Dent Mater 2024; 40:824-836. [PMID: 38521694 PMCID: PMC11098698 DOI: 10.1016/j.dental.2024.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/25/2024]
Abstract
OBJECTIVES The objective was to discuss the research on zirconia published in the past 15 years to help the dental materials community understand the key properties of the types of zirconia and their clinical applications. METHODS A literature search was performed in May/2023 using Web of Science Core Collection with the term "dental zirconia". The search returned 5102 articles, which were categorized into 31 groups according to the research topic. RESULTS The current approach to improving the translucency of zirconia is to decrease the alumina content while increasing the yttria content. The resulting materials (4Y-, 5Y-, and above 5 mol% PSZs) may contain more than 50% of cubic phase, with a decrease in mechanical properties. The market trend for zirconia is the production of CAD/CAM disks containing more fracture resistant 3Y-TZP at the bottom layers and more translucent 5Y-PSZ at the top. Although flaws located between layers in multilayered blocks might represent a problem, newer generations of zirconia layered blocks appear to have solved this problem with novel powder compaction technology. Significant advancements in zirconia processing technologies have been made, but there is still plenty of room for improvement, especially in the fields of high-speed sintering and additive manufacturing. SIGNIFICANCE The wide range of zirconia materials currently available in the market may cause confusion in materials selection. It is therefore imperative for dental clinicians and laboratory technicians to get the needed knowledge on zirconia material science, to follow manufacturers' instructions, and to optimize the design of the prosthetic restoration with a good understanding where to reinforce the structure with a tough and strong zirconia.
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Affiliation(s)
- Paulo Francisco Cesar
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil.
| | | | - Karina Felix Santos
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Susanne S Scherrer
- Division of Fixed Prosthodontics and Biomaterials, University Clinics of Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Yu Zhang
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, USA
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Omara AA, Othman HI, Aldamaty MF, Metwally MF. Effect of acidic environment on color and translucency of different indirect restorative materials. BMC Oral Health 2024; 24:472. [PMID: 38641578 PMCID: PMC11027526 DOI: 10.1186/s12903-024-04218-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 04/02/2024] [Indexed: 04/21/2024] Open
Abstract
PURPOSE The aim of the current study was to evaluate the effect of simulated gastric acid on the color and translucency of different indirect restorative materials. MATERIALS AND METHODS A total of 36 disc-shaped samples were cut by using an isomet saw and divided into four equal groups (n = 9) according to the material type: Group Z: translucent zirconia (Ceramill® Zolid ht.+ preshade, Amann Girrbach, Koblach, Austria); Group E: lithium disilicate (IPS e.max CAD, Ivoclar Vivadent AG, Schaan, Liechtenstein); Group C: resin nanoceramic (Cerasmart, GC, Tokyo, Japan); Group P: polyether ether ketone (PEEK) (Bettin Zirconia Dentale Italy) veneered with indirect high impact polymer composite (HIPC) (breCAM HIPC, Bredent GmbH & Co. KG, Germany). The samples were immersed in simulated gastric acid (HCl, pH 1.2) for 96 hours at 37 °C in an incubator. The color change (ΔE00) and translucency (RTP00) were measured every 9.6 hours (one-year clinical simulation) of immersion in simulated gastric acid. RESULTS For color change (∆E00) and translucency (RTP00) among the tested materials, there was a highly statistically significant difference (P < 0.001) after every year of follow-up. The color change in both Z and G groups was the lowest after 1 year of acid immersion, followed by that in group H, and the highest change in color was recorded in group P. CONCLUSION High translucent zirconia is recommended in patients who are concerned about esthetic, especially with acidic oral environment.
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Affiliation(s)
- Abdelaziz A Omara
- Department of Fixed Prosthodontics, Faculty of Dental Medicine, Misr University for Science and Technology, Cairo, Egypt
| | - Hesham I Othman
- Department of Fixed Prosthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, 11651, Egypt
| | - Mohamed F Aldamaty
- Department of Fixed Prosthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, 11651, Egypt.
| | - Mohamed F Metwally
- Department of Fixed Prosthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, 11651, Egypt
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Yang F, Zhang L, Yang M, Chen J, Xing W. The effect of deviations in sintering temperature on the translucency and color of multi-layered zirconia. BMC Oral Health 2024; 24:471. [PMID: 38637799 PMCID: PMC11027308 DOI: 10.1186/s12903-024-04243-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/09/2024] [Indexed: 04/20/2024] Open
Abstract
OBJECT This study aimed to investigate the changes in the translucency and color of four different multi-layered zirconia materials when the sintering temperature were inaccurate. MATERIALS AND METHODS Two hundred zirconia samples (11 × 11 × 1.0 mm) of four multi-layered zirconia, Upcera TT-GT (UG), Upcera TT-ML (UM), Cercon xt ML (CX), and Lava Esthetic (LE), were divided into five subgroups according to the sintering temperature: L1 (5% lower temperature), L2 (2.5% lower temperature), R (recommended sintering temperature), H2 (2.5% higher temperature), H1 (5% higher temperature). After sintering, color coordinates were measured. Then the translucency parameter (TP) values, and the color differences (between the inaccurate sintering temperature and the recommended temperature) of each zirconia specimen were calculated. Statistical analysis was performed by using three-way ANOVA tests, the one-way ANOVA, and Tukey's post hoc test. RESULTS Three-way ANOVA results showed that material type, sintering temperature, specimen section, and their interactions significantly influenced the TP values (except for the interactions of specimen section and sintering temperature) (P < .05). TP values of zirconia specimens were significantly different in the inaccurate sintering temperatures (P < .05), except for the cervical and body sections of UG group (P > .05). Compared with recommended sintering temperature, higher sintering temperature caused higher TP values for CX, but lower for LE. Three-way ANOVA results showed that material type, sintering temperature, and their interactions significantly influenced the ∆E00 values (P < .05). There were no significant differences in ∆E00 values of UM and CX groups at different inaccurate sintering temperatures, and were clinical imperception (except for UM-L1) (∆E00 < 1.25). ∆E00 values of all zirconia specimens showed clinically acceptable (∆E00 < 2.23). CONCLUSION The deviations in sintering temperature significantly influenced the translucency and color of tested multi-layered zirconia. The trends of translucency in the multi-layered zirconia depended on material type and the color changes of all zirconia materials were clinically acceptable at inaccurate sintering temperatures.
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Affiliation(s)
- Fan Yang
- Graduate School of Dalian Medical University, Dalian, China
| | - Luyao Zhang
- Graduate School of Dalian Medical University, Dalian, China
| | - Minghui Yang
- Dental Technology Center, Dalian Stomatological Hospital, Dalian, China
| | - Jianfeng Chen
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Wenzhong Xing
- Department of Prosthodontics, Dalian Stomatological Hospital, Dalian, Liaoning, 116021, PR China.
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Alshahrani AM, Lim CH, Wolff MS, Janal MN, Zhang Y. Current speed sintering and high-speed sintering protocols compromise the translucency but not strength of yttria-stabilized zirconia. Dent Mater 2024; 40:664-673. [PMID: 38378371 PMCID: PMC11015968 DOI: 10.1016/j.dental.2024.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/05/2024] [Accepted: 02/12/2024] [Indexed: 02/22/2024]
Abstract
OBJECTIVES To investigate the impacts of speed and high-speed sintering on the densification, microstructure, phase composition, translucency, and flexural strength of yttria-stabilized zirconia (YSZ). METHODS A total of 162 disc-shaped specimens (n = 18) were cold-isostatically pressed from 3YSZ (Zpex), 4YSZ (Zpex 4), and 5YSZ (Zpex Smile) powders (Tosoh Corporation) and sintered according to the following protocols: conventional (control, ∼12 h), speed (∼28 min for 3YSZ; ∼60 min for 4YSZ and 5YSZ), and high-speed (∼18 min) sintering. Dimensions of zirconia specimens after sintering and polishing (1-μm diamond grit finish) were Ø13.75 × 1 mm. Density, microstructure, phase content, translucency parameter, and biaxial flexural strength were evaluated using Archimedes', SEM, XRD, spectrophotometric, and piston-on-3-ball methods, respectively. Data were analyzed with either one-way ANOVA and Tukey's test or Kruskal-Wallis with Dunn's test (α = 0.05). RESULTS For all YSZ compositions, conventional sintering yielded the highest density followed by speed then high-speed sintering. All sintering protocols resulted in similar strength values; however, speed and high-speed sintering protocols afforded significantly lower translucency relative to conventional sintering. XRD analysis revealed similar spectra for YSZs sintered by various protocols. The speed sintered specimens had the smallest grain size whereas the high-speed sintered 5YSZ possessed the largest grain size among all groups. SEM examination of all YSZ compositions revealed that the average pore size was an order of magnitude smaller than the average grain size. SIGNIFICANCE Speed and high-speed sintering of YSZs yield similar strength but diminished density and translucency relative to their conventionally sintered counterparts.
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Affiliation(s)
- Abdulaziz M Alshahrani
- Laboratories for Microstructure Physics & Mechanics of Materials, Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Restorative Dental Sciences, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Chek Hai Lim
- Laboratories for Microstructure Physics & Mechanics of Materials, Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mark S Wolff
- Morton Amsterdam Dean, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malvin N Janal
- Department of Epidemiology & Health Promotion, New York University College of Dentistry, New York, NY 10010, USA
| | - Yu Zhang
- Laboratories for Microstructure Physics & Mechanics of Materials, Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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21
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Miura S, Shinya A, Koizumi H, Vallittu P, Lassila L, Fujisawa M. Effect of low-temperature degradation and sintering protocols on the color of monolithic zirconia crowns with different yttria contents. Dent Mater J 2024; 43:164-171. [PMID: 38296512 DOI: 10.4012/dmj.2023-194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
This study investigated the effects of low-temperature degradation (LTD) on the L*, a*, and b* values of highly translucent zirconia crowns. Four types of zirconia disks with different yttria contents (IPS e.max ZirCAD LT, IPS e.max ZirCAD MT, IPS e.max ZirCAD MT Multi, IPS e.max ZirCAD Prime, Ivoclar) and two shades (A2 and BL) were used. A crown was manufactured using four types of zirconia and LTD treated. Color measurements were performed, and the color difference (ΔE00) before and after LTD was calculated. The microstructure was determined through X-ray fluorescence and X-ray diffractometry. Highly translucent zirconia crowns showed greater changes in the a* and b* values than in the L* value after LTD, regardless of the shade. The Multi2 crowns exhibited a discernible color change due to the LTD treatment. The X-ray fluorescence results did not reveal any apparent change in the microstructure between sintering programs for all zirconia specimens.
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Affiliation(s)
- Shoko Miura
- Division of Fixed Prosthodontics, Department of Restorative and Biomaterials Sciences, Meikai University School of Dentistry
- Department of Biomaterials Science and Turku Clinical Biomaterials Center-TCBC, Institute of Dentistry, University of Turku
| | - Akikazu Shinya
- Department of Dental Materials Sciences, School of Life Dentistry at Tokyo, The Nippon Dental University
- Department of Prosthetic Dentistry and Biomaterials Science, Institute of Dentistry, University of Turku
| | - Hiroyasu Koizumi
- Department of Dental Materials, Nihon University School of Tokyo
| | - Pekka Vallittu
- Department of Biomaterials Science and Turku Clinical Biomaterials Center-TCBC, Institute of Dentistry, University of Turku
- Department of Prosthetic Dentistry and Biomaterials Science, Institute of Dentistry, University of Turku
- Welfare District of County of Southwest Finland
| | - Lippo Lassila
- Department of Biomaterials Science and Turku Clinical Biomaterials Center-TCBC, Institute of Dentistry, University of Turku
| | - Masanori Fujisawa
- Division of Fixed Prosthodontics, Department of Restorative and Biomaterials Sciences, Meikai University School of Dentistry
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22
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Yousry M, Hammad I, Halawani ME, Aboushelib M. Translucency of recent zirconia materials and material-related variables affecting their translucency: a systematic review and meta-analysis. BMC Oral Health 2024; 24:309. [PMID: 38443872 PMCID: PMC10913643 DOI: 10.1186/s12903-024-04070-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 02/25/2024] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND Recent forms of translucent zirconia material have been developed, offering a wide range of options and varieties for enhancing aesthetics, making it a preferred choice in the field of prosthetic dentistry. However, there is insufficient understanding regarding the recent types of zirconia materials and their optical behavior. Understanding the variables that influence the translucency of zirconia and identifying strategies to enhance its esthetics are crucial. PURPOSE The current systemic review highlights a comprehensive understanding of different zirconia generations in relation to their optical characteristics and evaluates material-related variables affecting their translucency. METHODS The present review studied in-vitro studies that evaluated the optical characteristics of different yttria content of yttria stabilized materials. The topics explored were: (1) the different zirconia material generations and their optical behavior; (2) material-related factors that affect their translucency. The research was restricted to online publication in the English language from July 1, 2010, to July 31, 2023, using PubMed, Scopus, and Science Direct resources. The search key terms and their combinations were "zirconia," "translucent zirconia," "cubic zirconia," "highly translucent zirconia," "yttria partially stabilized zirconia," "monolithic zirconia," "translucency," "optical properties," and "light transmission." RESULTS The data obtained from fifty-three studies addressed the optical characteristics of various zirconia generations. They reported that changing yttria content had a significant impact on translucency. Different kinds of zirconia ceramics of the same generation have varying translucencies. Achieving optimum aesthetics with monolithic zirconia is challenging due to factors related to material aspects such as the presence of additives, point defects, microstructure, thickness, phase distribution, and sintering conditions. CONCLUSIONS Newly developed monolithic dental zirconia ceramics have improved aesthetics and translucency. However, additional research is necessary to evaluate their performance and long-term durability. TRIAL REGISTRATION This systematic review was registered in PROSPERO, under number CRD42023474482.
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Affiliation(s)
- Mahinour Yousry
- Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
| | - Ihab Hammad
- Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Mohamed El Halawani
- Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Moustafa Aboushelib
- Department of Dental Materials Science, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
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23
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Labetić A, Klaser T, Skoko Ž, Jakovac M, Žic M. Flexural Strength and Morphological Study of Different Multilayer Zirconia Dental Materials. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1143. [PMID: 38473614 DOI: 10.3390/ma17051143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 03/14/2024]
Abstract
Nowadays, yttria (Y3+)-stabilized ZrO2 (Y-TZP) is the most commonly used material in dental prosthetics. Y-TZP dental ceramics are mainly stabilized via the addition of 3 mol% yttrium oxide (Y2O3). These ceramics exhibit excellent mechanical properties, including high flexural strength, fracture toughness, elastic modulus, etc. Some manufacturers have recently introduced a new class of dental materials with multilayer composition with the aim of combining the advantages of adding more or less Y2O3 to the ceramic composition in one Y-TZP material. The flexural strength values of multilayer Y-TZP may vary depending on the dimensions of the specimen, layer distributions, and especially the layer exposed on the maximum tension side, i.e., loading configuration. Although previous studies have examined the flexural strength of separate Y-TZP layers, capturing the flexural strength of multilayer Y-TZP is still challenging. However, one should keep in mind that multilayer flexural strength is important for clinical indications. The objective of this study is to compare the flexural strength of three distinct multilayer translucent Y-TZP materials made up of layers with different Y3+ contents. Rectangular samples (2 mm × 2 mm × 16 mm) were prepared from CAD/CAM discs using the milling machine Programill PM7 (Ivoclar Vivadent AG). Milled bars were tested for flexural strength in a three-point bending test (ISO 6872:2015) using a universal testing machine (Inspekt Duo 5kN; Hegewald & Peschke, Nossen, Germany) at a crosshead speed of 0.5 mm/min. Representative samples of each type of material were selected for quantitative and qualitative analysis of the microstructure. Representative samples of each type of material were selected for structural, mechanical, and microstructural analyses.
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Affiliation(s)
- Andrea Labetić
- University of Zagreb School of Dental Medicine, Gunduliceva 5, 10000 Zagreb, Croatia
| | - Teodoro Klaser
- Ruder Boskovic Institute, P.O. Box 180, 10000 Zagreb, Croatia
| | - Željko Skoko
- Department of Physics, Faculty of Science, University of Zagreb, Bijenicka, c. 32, 10000 Zagreb, Croatia
| | - Marko Jakovac
- University of Zagreb School of Dental Medicine, Gunduliceva 5, 10000 Zagreb, Croatia
| | - Mark Žic
- Ruder Boskovic Institute, P.O. Box 180, 10000 Zagreb, Croatia
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Benalcazar Jalkh EB, Ramalho IS, Bergamo ETP, Alves LMM, Tanaka R, Witek L, Coelho PG, Hirata R, Bonfante EA. Ultrathin lithium disilicate and translucent zirconia crowns for posterior teeth: Survival and failure modes. J ESTHET RESTOR DENT 2024; 36:381-390. [PMID: 37676053 DOI: 10.1111/jerd.13127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/07/2023] [Accepted: 08/10/2023] [Indexed: 09/08/2023]
Abstract
PURPOSE To evaluate the reliability and failure modes of ultrathin (0.5 mm) lithium disilicate, translucent and ultra-translucent zirconia crowns for posterior teeth restorations. MATERIALS AND METHODS Fifty-four mandibular first molar crowns of three ceramic materials: (1) Lithium disilicate (e.max CAD, Ivoclar Vivadent), (2) 3Y-TZP (Zirconn Translucent, Vipi), and (3) 5Y-PSZ (Cercon XT, Dentsply Sirona), with 0.5 mm of thickness were milled and cemented onto composite resin abutments. Eighteen samples of each group were tested under mouth-motion step-stress accelerated life testing in a humid environment using mild, moderate, and aggressive profiles. Data was subjected to Weibull statistics. Use level curves were plotted and reliability was calculated for a given mission of 100,000 cycles at 100, 200, and 300 N. Fractographic analyses of representative samples were performed in scanning electron microscope. RESULTS Beta (β) values suggest that failures were dictated by material's strength for lithium disilicate and by fatigue damage accumulation for both zirconias. No significant differences were detected in Weibull modulus and characteristic strength among groups. At a given mission of 100,000 cycles at 100 N, lithium disilicate presented higher reliability (98% CB: 95-99) regarding 3Y-TZP and 5Y-PSZ groups (84% CB: 65%-93% and 79% CB: 37&-94%, respectively). At 200 N, lithium disilicate reliability (82% CB: 66%-91%) was higher than 5Y-PSZ (20% CB: 4%-44%) and not significantly different from 3Y-TZP (54% CB: 32%-72%). Furthermore, at 300 N no significant differences in reliability were detected among groups, with a notable reduction in the reliability of all materials. Fractographic analyses showed that crack initiated at the interface between the composite core and the ceramic crowns due to tensile stress generated at the intaglio surface. CONCLUSIONS Ultrathin lithium disilicate crowns demonstrated higher reliability relative to zirconia crowns at functional loads. Lithium disilicate and zirconia crown's reliability decreased significantly for missions at higher loads and similar failure modes were observed regardless of crown material. The indication of 0.5 mm thickness crowns in high-load bearing regions must be carefully evaluated. CLINICAL SIGNIFICANCE Ultraconservative lithium disilicate and zirconia crowns of 0.5 mm thickness may be indicated in anterior restorations and pre-molars. Their clinical indication in high-load requirement regions must be carefully evaluated.
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Affiliation(s)
- Ernesto B Benalcazar Jalkh
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - Ilana S Ramalho
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - Edmara T P Bergamo
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
- Biomaterials Division, New York University College of Dentistry, New York, New York, USA
- Department of Prosthodontics, New York University College of Dentistry, New York, New York, USA
| | - Larissa M M Alves
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | | | - Lukasz Witek
- Biomaterials Division, New York University College of Dentistry, New York, New York, USA
- Department of Biomedical Engineering, New York Univeristy Tandon School of Engineering, Brooklyn, New York, USA
| | - Paulo G Coelho
- DeWitt Daughtry Family Department of Surgery, Division of Plastic Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ronaldo Hirata
- Biomaterials Division, New York University College of Dentistry, New York, New York, USA
| | - Estevam A Bonfante
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
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Uasuwan P, Juntavee N, Juntavee A. Optical Characteristics of Monochrome and Multilayer Fully Stabilized Zirconia Upon Sintered Cooling Speed. Eur J Dent 2024; 18:196-207. [PMID: 37059447 PMCID: PMC10959634 DOI: 10.1055/s-0043-1764233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023] Open
Abstract
OBJECTIVES Firing protocols influence optical properties of dental ceramics. Effects of varying cooling rates of monochrome and multilayer 5 mol% yttria-stabilized tetragonal polycrystalline (5YTZP) on optical properties are subjected for investigation. MATERIALS AND METHODS Ninety specimens (width, length, thickness = 10 × 20 × 2 mm) were prepared from monochrome (Mo: Cercon xt) and multilayer (Mu: Cercon xt ML with cervical (C) and incisal (I) zoning) 5YTZP. Specimens were sintered and randomly treated with three cooling rates (n = 15/group): slow (S: 5°C/min), normal (N: 35°C/min), and fast (F: 70°C/min). Color appearance (∆EW), color appearance difference (∆E diff), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were evaluated in CIEL*a*b* (Commission International de I'Eclairage) system. ∆E diff was achieved from the coordinate difference of specimen to VITA classic shade A2. Microstructures and compositions were evaluated by scanning electron microscope and energy dispersive spectroscopy. Monoclinic (m), tetragonal (t), and cubic (c) phases were investigated with X-ray diffraction. STATISTICAL ANALYSIS An analysis of variance and Bonferroni multiple comparisons were determined for significant differences (p < 0.05). RESULTS ΔEW of MoF was highest (66.04 ± 1.86), while MuN-I was lowest (62.60 ± 0.86). TP and OP of MoS were highest at 2.85 ± 0.11, and 2.25 ± 0.10, while MuF-I was lowest at 2.16 ± 0.10 and 1.60 ± 0.12. CR of MuF-I was highest (0.948 ± 0.005), while MoS was lowest (0.936 ± 0.005). ΔEdiff of MoF was highest (3.83), while MuN-I was lowest (0.93). Limited grain growth and m-phase composition were indicated upon fast cooling. There were significant differences for all color parameters due to varied materials, cooling rates, and their interactions (p < 0.05) except for interaction in ∆EW and OP. CONCLUSIONS Translucency of monochrome and multilayer 5YTZP were different, possibly due to colorant additives. Incisal layer of multilayer 5YTZP was perfectly matched with VITA shade. Increasing cooling speed resulted in smaller grain size, t-m transformation, and finally lower translucency and opalescence. Therefore, to achieve most favorable optical properties, slow cooling rate is recommended.
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Affiliation(s)
- Pithiwat Uasuwan
- Division of Biomaterials and Prosthodontics Research, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Niwut Juntavee
- Department of Prosthodontics, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Apa Juntavee
- Division of Pediatric Dentistry, Department of Preventive Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
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Suliman S, Sulaiman TA, Deeb JG, Abdulmajeed A, Abdulmajeed A, Närhi T. Er:YAG laser debonding of zirconia and lithium disilicate restorations. J Prosthet Dent 2024; 131:253.e1-253.e6. [PMID: 37951718 DOI: 10.1016/j.prosdent.2023.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 11/14/2023]
Abstract
STATEMENT OF PROBLEM Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) restorations of different formulations are being used increasingly in monolithic form for a range of clinical applications. Using rotary instruments to remove such restorations for any purpose is challenging, but they can be removed conservatively with erbium lasers. However, studies on how a laser penetrates different zirconias to break the cement bond between the tooth surface and the zirconia are lacking. PURPOSE The purpose of this in vitro study was to evaluate and compare the time required for an erbium-doped yttrium-aluminum-garnet (Er:YAG) laser to remove different types of zirconia and lithium disilicate crowns. MATERIAL AND METHODS Forty extracted premolar teeth were prepared, scanned, designed, and milled to fabricate 40 computer-aided design and computer-aided manufacturing (CAD-CAM) crowns, which were assigned to 4 groups (n=10): 3 mol% Y-TZP, 4 mol% Y-TZP, 5 mol% Y-TZP, and lithium disilicate as a control. All crowns were bonded to the teeth with a self-adhesive resin cement (Panavia SA Cement Universal). Each specimen was irradiated with an Er:YAG laser with the following parameters: 300 mJ, 15 Hz, 5.0 W, and a 50-microsecond pulse duration (supershort pulse mode). The irradiation time required for crowns to be retrieved successfully was recorded for each specimen. Data were statistically analyzed using analysis of variance and the Tukey honestly significant difference post hoc test (α=.05). The intaglio surfaces of the restorations were analyzed using scanning electron microscopy (SEM). RESULTS The mean ±standard deviation times in minutes needed for crown debonding were 12.46 ±4.17 for the 3 mol% Y-TZP group, 10.30 ±3.33 for the 4 mol% Y-TZP group, 4.03 ±1.62 for the 5 mol% Y-TZP group, and 2.08 ±0.92 for the lithium disilicate group. A statistically significant difference (P<.05) in the debonding time was found for all investigated groups, expect between the 3 mol% and 4 mol% Y-TZP groups and between the 5 mol% Y-TZP and lithium disilicate groups. SEM analysis of the ceramic surfaces showed no visual damage associated with Er:YAG laser irradiation. CONCLUSIONS Zirconia crown retrieval time with the Er:YAG laser was influenced by the yttria content of the zirconia, with decreasing retrieval time with increasing yttria content. Er:YAG laser debonding of zirconia crowns is a noninvasive, efficient, and rapid approach to the removal of crowns and could be applied in clinical practice.
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Affiliation(s)
- Sama Suliman
- Doctoral student, Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland; and Lecturer, Department of Preventive and Restorative Dentistry, College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Taiseer A Sulaiman
- Associate Professor, Division of Comprehensive Oral Health, Adams School of Dentistry, University of North Carolina at Chapel Hill, NC.
| | - Janina Golob Deeb
- Professor, Department of Periodontics, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia
| | - Awab Abdulmajeed
- Assistant Professor, Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia
| | - Aous Abdulmajeed
- Associate Professor, Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia
| | - Timo Närhi
- Professor, Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland
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Sudharson NA, Gandhi N, Talwar H, Kurian N, Joseph M. A comparative analysis of mechanical and optical behavioral patterns of translucent zirconia ceramics. J Indian Prosthodont Soc 2024; 24:88-94. [PMID: 38263563 PMCID: PMC10896311 DOI: 10.4103/jips.jips_341_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/28/2023] [Accepted: 12/23/2023] [Indexed: 01/25/2024] Open
Abstract
AIM This research aimed to assess and compare the translucency and mechanical properties of partially stabilized zirconia in contrast to lithium disilicate, particularly within the context of translucent zirconia. SETTINGS AND DESIGN The experimental design entails examining fifty samples, with ten drawn from each of the five distinct categories of ceramic materials, as part of this in vitro study. Translucency is measured using the Konica Minolta CM-3600D spectrophotometer, assessing Delta E through Lab values against white and black backgrounds. Flexural strength is analyzed via a 3-point bend test on a universal testing machine, with a controlled crosshead speed set at 1 mm/min. MATERIALS AND METHODS The study included the five categories of ceramic materials, each consisting of ten samples: High-strength zirconia (Katana HT), translucent zirconia (e.max Zircad MT and Cercon ht ML), and lithium disilicate (Press MT and LT). The Konica Minolta CM-3600D spectrophotometer is utilized to measure the translucency parameter. This involves determining the color difference (Delta E) by comparing the L*a*b values against both white and black backgrounds. The flexural strength (FS) of zirconia and lithium disilicate materials was analyzed through a 3-point bend test, aiming to compare their respective strengths. The testing procedure was carried out on a universal testing machine with a controlled crosshead speed set at 1 mm/min. The FS was calculated using the formula σ = FL/πR3 for circular disks, where σ represents the FS, F is the fracture load, L is the span length in millimeters, and R is the radius of the disk. STATISTICAL ANALYSIS USED The Student's t-test was employed for statistical analysis. RESULTS The mean translucency parameter for e.max Press MT (6.33 ± 1.05) was significantly greater than all the specimens investigated. The Cercon ht ML exhibited a slightly higher translucency (2.18 ± 0.52) compared to e.max Zircad MT (1.49 ± 0.69), with a statistically significant difference (P = 0.022). Conversely, the FS of e.max Zircad MT (26.97 ± 2.06) was significantly greater (P < 0.001) than that of Cercon ht ML (23.25 ± 2.36). Notably, the Katana HT material demonstrated the highest load strength (32.92 ± 3.10), a statistically significant difference compared to its counterparts (P < 0.001). CONCLUSIONS Among the materials tested, lithium disilicate ceramics exhibited the highest translucency, with its MT variant demonstrating the lowest strength. Katana HT displayed significantly greater biaxial FS compared to translucent zirconia, surpassing even lithium disilicate. Translucent zirconia proved to be notably more translucent than high-strength zirconia. Within the category of translucent zirconia, e.max Zircad MT exhibited substantially higher FS than Cercon.
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Affiliation(s)
| | - Nitasha Gandhi
- Department of Prosthodontics, Christian Dental College, Ludhiana, Punjab, India
| | - Harit Talwar
- Department of Prosthodontics, Christian Dental College, Ludhiana, Punjab, India
| | - Nirmal Kurian
- Department of Prosthodontics, Christian Dental College, Ludhiana, Punjab, India
| | - Meril Joseph
- Department of Prosthodontics, Christian Dental College, Ludhiana, Punjab, India
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Sulaiman TA, Suliman AA, Abdulmajeed AA, Zhang Y. Zirconia restoration types, properties, tooth preparation design, and bonding. A narrative review. J ESTHET RESTOR DENT 2024; 36:78-84. [PMID: 37840220 PMCID: PMC10842315 DOI: 10.1111/jerd.13151] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/01/2023] [Accepted: 10/03/2023] [Indexed: 10/17/2023]
Abstract
OBJECTIVE The purpose of this review was to provide dental professionals with information regarding the various types of zirconia restorations, their mechanical and optical properties, tooth preparation design, and bonding protocol in an effort to enhance the longevity and durability of zirconia restorations. OVERVIEW The yttria content of zirconia ceramics determines their classification. The mechanical and optical properties of each type are discussed, with an emphasis on the effect of yttria concentration on the properties of zirconia. The processing and sintering methods are also discussed as they have a direct impact on the properties of zirconia. The design of tooth preparation, specifically occlusal reduction, varies depending on the type of zirconia used in each case. Finally, a protocol for zirconia restoration bonding is described to ensure optimal bonding to the tooth structure. CONCLUSION Not all zirconia restorations are the same. The selection of zirconia type based on yttria concentration, processing and sintering methods, tooth preparation design, and adherence to the bonding protocol are all critical to the success and longevity of zirconia restorations. CLINICAL SIGNIFICANCE Zirconia restorations are the most commonly used indirect restorative material. The selection of the most appropriate zirconia type based on its yttria content, which determines its strength and translucency, is critical to the success and the longevity of the restoration. Tooth preparation design also influences the strength and translucency of the zirconia. Air-borne particle abrasion, followed by a ceramic primer and resin cement, can ensure a durable bond to the tooth structure.
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Affiliation(s)
- Taiseer A Sulaiman
- Division of Comprehensive Oral Health, University of North Carolina, Adams School of Dentistry, Chapel Hill, North Carolina, USA
| | - Abdulhaq A Suliman
- Department of Clinical Sciences, College of Dentistry, Ajman University, Ajman, UAE
| | - Aous A Abdulmajeed
- Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Yu Zhang
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Nasir MQ, kadhim AJ. Marginal adaptation of different monolithic zirconia crowns with horizontal and vertical finish lines: A comparative in vitro study. J Dent Res Dent Clin Dent Prospects 2023; 17:235-241. [PMID: 38584994 PMCID: PMC10998165 DOI: 10.34172/joddd.2023.40589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/25/2023] [Indexed: 04/09/2024] Open
Abstract
Background This study evaluated the influence of different tooth preparation techniques and zirconia materials on marginal adaptation. Methods Forty-eight healthy human maxillary first premolars were divided into two primary groups based on preparation design: group A (chamfer) and group B (vertical). Within each main group, there were three subgroups, comprising eight teeth each, distinguished by the type of zirconia material employed (Zircad LT, MT, and Prime by Ivoclar Vivadent). All the samples were prepared by the same operator using a dental surveyor. Intraoral scanning was performed on the prepared teeth. SironaInLab CAD 20.0 software was used to design crowns, which were subsequently generated using a 5-axis milling machine. The crowns were cemented to their respective teeth with self-adhesive resin cement. Marginal gap measurements were taken in micrometers (μm) before and after cementation at 16 sites per sample using a digital microscope at×230 magnification. The collected data were evaluated using statistical analysis using the independent t-test, paired t-test, and ANOVA at an 0.05 significance level. Results The vertical preparation group exhibited the smallest marginal gap, while the chamfer group displayed the largest. This disparity was statistically significant (P<0.05) for pre- and post-cementation measurements across all materials. There were no significant differences between the different monolithic zirconia crowns. Conclusion The vertical preparation design illustrated significantly better marginal adaptation than the chamfer preparation design. Comparisons between materials showed comparable marginal gaps. The mean values of the marginal gaps in all groups increased significantly after cementation.
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Affiliation(s)
- Mohammed Qasim Nasir
- Department of Restorative and Aesthetic Dentistry, College of Dentistry, University of Baghdad, Baghdad, Iraq
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Benalcázar-Jalkh EB, Bergamo ETP, Campos TMB, Coelho PG, Sailer I, Yamaguchi S, Alves LMM, Witek L, Tebcherani SM, Bonfante EA. A Narrative Review on Polycrystalline Ceramics for Dental Applications and Proposed Update of a Classification System. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7541. [PMID: 38138684 PMCID: PMC10744432 DOI: 10.3390/ma16247541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/07/2023] [Accepted: 11/25/2023] [Indexed: 12/24/2023]
Abstract
Dental zirconias have been broadly utilized in dentistry due to their high mechanical properties and biocompatibility. Although initially introduced in dentistry as an infrastructure material, the high rate of technical complications related to veneered porcelain has led to significant efforts to improve the optical properties of dental zirconias, allowing for its monolithic indication. Modifications in the composition, processing methods/parameters, and the increase in the yttrium content and cubic phase have been presented as viable options to improve zirconias' translucency. However, concerns regarding the hydrothermal stability of partially stabilized zirconia and the trade-off observed between optical and mechanical properties resulting from the increased cubic content remain issues of concern. While the significant developments in polycrystalline ceramics have led to a wide diversity of zirconia materials with different compositions, properties, and clinical indications, the implementation of strong, esthetic, and sufficiently stable materials for long-span fixed dental prostheses has not been completely achieved. Alternatives, including advanced polycrystalline composites, functionally graded structures, and nanosized zirconia, have been proposed as promising pathways to obtain high-strength, hydrothermally stable biomaterials. Considering the evolution of zirconia ceramics in dentistry, this manuscript aims to present a critical perspective as well as an update to previous classifications of dental restorative ceramics, focusing on polycrystalline ceramics, their properties, indications, and performance.
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Affiliation(s)
- Ernesto B. Benalcázar-Jalkh
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru 17012-901, SP, Brazil
| | - Edmara T. P. Bergamo
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru 17012-901, SP, Brazil
- Biomaterials Division, NYU Dentistry, New York, NY 10010, USA
- Department of Prosthodontics, NYU Dentistry, New York, NY 10010, USA
| | - Tiago M. B. Campos
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru 17012-901, SP, Brazil
| | - Paulo G. Coelho
- DeWitt Daughtry Family Department of Surgery, Division of Plastic Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Irena Sailer
- Division of Fixed Prosthodontics and Biomaterials, University Clinics of Dental Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Satoshi Yamaguchi
- Department of Dental Biomaterials, Osaka University Graduate School of Dentistry, Suita 565-0871, Osaka, Japan;
| | - Larissa M. M. Alves
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru 17012-901, SP, Brazil
| | - Lukasz Witek
- Biomaterials Division, NYU Dentistry, New York, NY 10010, USA
- Department of Biomedical Engineering, NYU Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA
- Hansjörg Wyss Department of Plastic Surgery, NYU Grossman School of Medicine, New York, NY 10017, USA
| | - Sérgio M. Tebcherani
- Department of Production Engineering, Federal University of Technology—Paraná, Av. Monteiro Lobato Km 04, Ponta Grossa 84016-210, PR, Brazil;
| | - Estevam A. Bonfante
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru 17012-901, SP, Brazil
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Yousry MA, Hammad IA, El Halawani MT, Aboushelib MN. Effect of sintering time on microstructure and optical properties of yttria-partially stabilized monolithic zirconia. Dent Mater 2023; 39:1169-1179. [PMID: 37845165 DOI: 10.1016/j.dental.2023.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/12/2023] [Accepted: 10/05/2023] [Indexed: 10/18/2023]
Abstract
OBJECTIVES To evaluate the impact of speed sintering on the microstructure and optical properties of 3 and 5 mol% yttria-partially stabilized monolithic zirconias. METHODS 120 plate-shaped zirconia specimens (10x10x 0.4 mm) were prepared from three commercial 5 mol% yttria-partially stabilized zirconia blocks (5Y-PSZs); Katana UTML (Kuraray Noritake), Cercon xtML (Dentsply Sirona), and Zolid FX white (Amann Girrbach), and two commercial 3 mol% yttria-partially stabilized zirconia blocks (3Y-PSZs); Lava Plus (3 M ESPE) and InCoris (Sirona, GmbH). Specimens were either conventional sintered (CS) using a 7-hour program or speed sintered (SS) using a quick 90-minute program. The microstructure was inspected with a scanning electron microscope (SEM), and phase fractions were detected using x-ray diffraction analysis (XRD). Translucency (TP00), and contrast ratio (CR) were obtained using a spectrophotometer (VITA Easyshade V). Color difference (ΔE00) between both sintering processes was calculated with the CIEDE2000 formula. ΔE00 up to 1.8 was set as the acceptability threshold. Data were analyzed using two-way ANOVA, Krusakll-Wallis, and Mann-Whitney U tests. (n = 12, α = .05). RESULTS Grain size was significantly decreased after SS for all tested materials (P < .0001). The average grain sizes of 5Y-PSZs were significantly larger than those of 3Y-PSZs. The atomic structure, microstructure, and transparency of CS and SS were all affected by the amount of yttria, the size of the crystals, and tetragonality. SS significantly reduced TP00 (F = 7135.95, P < 0.0001) and increased CR (F = 453.21, P < 0.0001). The CS Katana presented the highest TP00 and lowest CR value. ΔE00 between the CS and SS groups were clinically acceptable except for Lava, which had values above the set threshold (1.89). SIGNIFICANCE SS altered the grain size and internal structure of the tested materials, which was reflected in translucency.
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Affiliation(s)
- Mahinour A Yousry
- Division of Fixed Prosthodontics, Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
| | - Ihab A Hammad
- Division of Fixed Prosthodontics, Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Mohamed T El Halawani
- Division of Fixed Prosthodontics, Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Moustafa N Aboushelib
- Department of Dental Materials Science, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
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Hafezeqoran A, Sabanik P, Koodaryan R, Ghalili KM. Effect of sintering speed, aging processes, and different surface treatments on the optical and surface properties of monolithic zirconia restorations. J Prosthet Dent 2023; 130:917-926. [PMID: 35109985 DOI: 10.1016/j.prosdent.2021.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 12/01/2021] [Accepted: 12/01/2021] [Indexed: 11/24/2022]
Abstract
STATEMENT OF PROBLEM Advances in dentistry have led to more esthetic and biocompatible restorative materials such as translucent zirconia and to faster and more accurate manufacturing methods. How changes in the surface and optical properties of translucent zirconia affect the esthetics and durability of these restorations under different conditions and manufacturing processes is unclear. PURPOSE The purpose of this in vitro study was to evaluate the effect of the sintering speed, aging process, and different surface treatments on the translucency and surface structure of monolithic zirconia restorations. MATERIAL AND METHODS Prepared typodont teeth were scanned, and 40 three-unit fixed partial dentures (FPDs) and 40 disk specimens were designed and prepared from monolithic zirconia blanks. The specimens were divided into traditional or speed sintering groups (20 FPDs and 20 disks each); half of each group (10 FPDs and 10 disks) was polished with a handpiece at 10 000 rpm, and the other half was glazed. Half of the specimens were thermocycled with 3500 cycles in 5 °C and 55 °C water baths, and the remaining half were not thermocycled. Translucency was measured with a spectrophotometer. Surface free energy was calculated in mNm with a contact angle device; surface roughness was measured in nm with an atomic force microscope. Translucency data were analyzed by the Kruskal-Wallis and Mann-Whitney tests, while surface free energy and surface roughness data were analyzed by 3-way ANOVA (α=.05). RESULTS The highest transmittance was in the speed sintered, polished, nonthermocycled group, and the lowest transmittance was in the speed sintered, polished, thermocycled group (P=.029). The transmittance of the traditionally sintered, polished, nonthermocycled group was significantly higher than that in all the speed sintered, glazed groups; the traditionally sintered, glazed groups; and the traditionally sintered, polished, thermocycled group (P=.029). The transmittance of the traditionally sintered, polished, thermocycled group was significantly higher than that of all traditionally sintered, glazed groups (P=.029). The mean surface free energy in the traditionally sintered groups was higher than that in the speed sintered groups (P=.002); also, it was higher in the glazed groups than in the polished groups (P<.001). The aging process decreased surface free energy (P=.023). The mean surface roughness in the speed sintered groups was significantly lower than that in the traditionally sintered groups (P=.004). No significant difference in surface roughness was found between the polished and glazed groups and between the 2 variables of the aging process (P>.05). CONCLUSIONS Speed sintering and polishing may decrease the surface free energy and increase the translucency of the monolithic zirconia restoration. Also, speed sintering creates a smoother surface. Aging had a more significant effect on decreasing the surface free energy of the specimens and could make the least translucent restorations.
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Affiliation(s)
- Ali Hafezeqoran
- Associate Professor, Prosthodontics, Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, East Azerbaijan Province, Iran
| | - Pouya Sabanik
- Private practice, Tabriz, East Azerbaijan Province, Iran.
| | - Roodabeh Koodaryan
- Associate Professor, Prosthodontics, Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, East Azerbaijan Province, Iran
| | - Kambiz M Ghalili
- Clinical Professor, Prosthodontics, Department of Prosthodontics, College of Dentistry, New York University, New York City, NY; Private practice, New York City, NY
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Du Q, Cui T, Niu G, Qui J, Yang B. Improving Bond Strength of Translucent Zirconia Through Surface Treatment With SiO2-ZrO2 Coatings. Oper Dent 2023; 48:666-676. [PMID: 37961015 DOI: 10.2341/22-121-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2023] [Indexed: 11/15/2023]
Abstract
BACKGROUND Translucent monolithic zirconia ceramics have been applied in dental clinics due to their esthetic translucent formulations and mechanical properties. Considering inherent ceramic brittleness, adhesive bonding with resin composite increases the fracture resistance of ceramic restorations. However, zirconia is a chemically stable material that is difficult to adhesively bond with resin. OBJECTIVES To investigate the influences of SiO2-ZrO2 coatings on adhesive bonding of zirconia and the surface characterization of those coatings. METHODS AND MATERIALS Translucent zirconia discs were classified into groups based on surface treatments: CT (control), SB (sandblasting), C21(SiO2:ZrO2=2:1), C11(SiO2:ZrO2=1:1), and C12 (SiO2:ZrO2=1:2) (n=10). Surface characterization of coatings on zirconia were analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness assessment (Ra), X-ray diffraction (XRD), water contact angle (WCA), translucency parameter (TP), and shear bond strength (SBS). Two-way ANOVA for shear bond strength results and ANOVA for Ra and WCA were performed. RESULTS SEM images revealed SiO2 islands on zirconia disks coated with SiO2-ZrO2. Surface roughness of C12, C11, and C21 groups was significantly larger than those of groups SB and CT (p<0.05). XRD results showed that phase transformation of zirconia disks was detected only in the SB group. In addition, SiO2-ZrO2 coatings reduced WCA. The translucency decreased only in group C21. Group C11 showed the highest shear bond strength under both aging conditions. CONCLUSION SiO2-ZrO2 coating is a promising method to enhance the adhesive resin bonding of translucent zirconia without causing phase transformation of translucent zirconia.
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Affiliation(s)
- Q Du
- †Qiao Du, DDS, Department of Stomatology, Beijing Integrated Traditional Chinese and Western Medicine Hospital, Beijing, China
| | - T Cui
- †Tiehan Cui, DDS, Department of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - G Niu
- *Guangliang Niu, DDS, Department of Stomatology,Beijing Integrated Traditional Chinese and Western Medicine Hospital, Beijing, China
| | - J Qui
- *Jiaxuan Qui, DDS, Department of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - B Yang
- *Bin Yang, DDS, Restorative Department, College of Dentistry, University of Illinois at Chicago, IL, USA
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Adak IO, Aguloglu S, Adak BM, Sari I. Comparison of the translucency parameters and bond strength of 5Y-ZP zirconia, 3-YTZP zirconia, and lithium disilicate. Niger J Clin Pract 2023; 26:1491-1497. [PMID: 37929525 DOI: 10.4103/njcp.njcp_91_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Background E-max is a more aesthetic material than traditional zirconia. In addition, the bond strength of traditional zirconia with adhesive cements is lower. There are not enough studies on how the aesthetic values and bond strength of 5-YZP, the new generation zirconia, compare to e-max and traditional zirconia. Can 5-YZP be an alternative to e-max in terms of aesthetics and bond strength? Aim The aim of the study is to compare the translucency property and bonding ability of 5y-zp zirconias with previous generation zirconias and lithium disilicate. Materials and Methods Two types of zirconia Katana UT and Katana HT for measuring translucency values; and using a type of lithium disilicate IPS e.max CAD LT, three groups were formed (n = 10). Translucency specimens were fabricated (n = 10). Their L*a*b* values were measured against a black-and-white background with a spectrophotometer, and DE00 was calculated. To perform micro-shear tests, a cylinder design was made from zirconia and IPS e.max CAD blocks (n = 20). After the samples were aged by thermal cycle, the micro-shear test was applied to specimens cemented to teeth extracted with two different adhesive cement systems. Results According to the results of one-way analysis of variance, a statistically significant difference was found between the translucency parameter (TP) values of the groups. According to Tukey's honestly significant difference (HSD) multiple comparisons, the values of the three groups are statistically different from each other. Although IPS e.max CAD group has the highest TP values, the Katana HT group has the lowest values. Conclusion 5Y-PZ has a TP intermediate to those of 3Y-TZP and lithium disilicate. Long-term bond strength of 3Y-TZP and 5Y-ZP were similar to those of lithium disilicate. To be an alternative to glass ceramics in the anterior region, translucency and bond strength values need to be improved.
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Affiliation(s)
- I Ozkan Adak
- Department of Prosthetic Dentistry, Izmir Katip Celebi University, Izmir, Turkey
| | - S Aguloglu
- Department of Prosthetic Dentistry, Izmir Katip Celebi University, Izmir, Turkey
| | - B M Adak
- Deparment of Oral and Maxillofacial Surgery, Izmir Katip Celebi University, Izmir, Turkey
| | - I Sari
- Department of Prosthetic Dentistry, Izmir Katip Celebi University, Izmir, Turkey
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Giugliano TS, Zhang Y, Janal MN, Lim CH, Smith RM, Choi M. In vitro comparison of physical characteristics of milled versus printed zirconia discs. J Prosthodont 2023:10.1111/jopr.13778. [PMID: 37776103 PMCID: PMC10980599 DOI: 10.1111/jopr.13778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 10/01/2023] Open
Abstract
PURPOSE The purpose of this study was to compare the dimensional accuracy, translucency, and biaxial flexural strength of milled zirconia (MZ) versus 3D-printed zirconia (PZ) discs. MATERIALS & METHODS A circular disc measuring 14.0 mm in diameter and 1.20 mm in thickness was designed using computer-aided design (CAD) software. The resulting standard tessellation language (STL) file was used both as a control and to fabricate 36 zirconia (3Y-TZP) disc specimens (n = 36): 18 were milled (group MZ) and 18 were 3D-printed (group PZ). The diameter and thickness of each disc were measured using a digital caliper. Translucency was evaluated using a calibrated dental colorimeter. The flexural strength was determined using the piston-on-three-ball biaxial flexure test. All measurements were done by one blinded examiner. The statistical significance level was set to α = 0.05. RESULTS The MZ discs had significantly more accurate dimensions than the PZ discs in both diameter and thickness when compared to the control CAD software-designed disc. The MZ discs exhibited significantly higher translucency (translucency parameter (TP) = 16.95 ±0.36 vs. 9.24 ±1.98) and biaxial flexural strength (996.16 ±137.37 MPa vs. 845.75 ±266.16 MPa) than the PZ discs. Finally, MZ possessed a significantly higher Weibull modulus relative to PZ. CONCLUSIONS The results showed that the milled specimens achieved better dimensional accuracy and were more translucent, stronger, and less prone to failure than printed specimens.
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Affiliation(s)
- Thomas S. Giugliano
- Department of Prosthodontics, New York University College of Dentistry, New York, NY
| | - Yu Zhang
- Laboratories for Microstructure Physics & Mechanics of Materials, Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA
| | - Malvin N. Janal
- Department of Epidemiology & Health Promotion, New York University College of Dentistry, New York, NY
| | - Chek Hai Lim
- Laboratories for Microstructure Physics & Mechanics of Materials, Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ruby M. Smith
- Post-Graduate Student, Department of Prosthodontics, New York University College of Dentistry, New York, NY
| | - Mijin Choi
- Department of Prosthodontics, New York University College of Dentistry, New York, NY
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Soares PM, Pereira GKR, Bacchi A. Resin composite layering on discolored substrates ensures masking ability for monolithic ceramics. J ESTHET RESTOR DENT 2023; 35:860-868. [PMID: 37209028 DOI: 10.1111/jerd.13066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/18/2023] [Accepted: 05/09/2023] [Indexed: 05/21/2023]
Abstract
OBJECTIVE the aim of this study was to evaluate the effect of resin composite layering on discolored substrates to obtain masking ability with monolithic ceramics. MATERIALS AND METHODS Four groups (n = 8) of computer-aided design/computer aided manufacturing (CAD/CAM) monolithic ceramics, shade A1, with thicknesses of 1.0 and 1.5 mm, were tested: feldspathic (FC), leucite-reinforced (LC), lithium disilicate-reinforced (LD), and translucent zirconia (5YSZ). Five substrates were used: A1 (used as reference), A3.5, C4, and coppery and silvery metals. The substrates were separated as non-layered or layered (with flowable opaque resin composite (FL), white opaque restorative resin composite (WD), and A1-shaded opaque restorative resin composite (A1D)). Resin composite layers of 0.5 and 1.0 mm were tested. The try-in paste, shade A1, was used as a luting agent. Translucency parameter (TP00 ) was assessed for the ceramics. Color differences (∆E00 ) were assessed for the restorative ceramics and resin composite layers over discolored substrates with the CIEDE2000 formula. The results were compared statistically, and descriptively with acceptability (AT, 1.77) and perceptibility (PT, 0.81) thresholds. RESULTS Feldspathic showed the highest TP00 (for both ceramic thicknesses) and LD the lowest (for 1.5 mm of ceramic thickness) (P < 0.001). For substrate A3.5, layering with 1.0 mm of A1D or WD ensured ∆E00 below PT for all ceramics tested (P < 0.001). The use of 0.5 mm of FL or 1.0 mm of A1D associated with ceramics LC, LD, and 5YSZ ensured ∆E00 below AT for substrates C4 and coppery metal (P < 0.001). Silvery background layered with 0.5 mm of FL presented ∆E00 below AT for all ceramics and ∆E00 below PT for lithium disilicate of 1.0 mm of thickness (∆E00 = 0.72). CONCLUSIONS Layering severely discolored substrates with selected opaque resin composites ensures masking ability for restoration with CAD/CAM monolithic ceramics. CLINICAL SIGNIFICANCE Severely discolored substrates are predictably restored with monolithic CAD/CAM ceramics by performing a previous layering of the substrate with opaque resin composite.
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Affiliation(s)
- Pablo Machado Soares
- Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Gabriel Kalil Rocha Pereira
- Post-Graduate Program in Oral Sciences (Prosthodontics Unit), Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Atais Bacchi
- MSciD Post-Graduate Program in Dentistry, Paulo Picanço School of Dentistry (FACPP), Fortaleza, Brazil
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Schabbach LM, Dos Santos BC, De Bortoli LS, Fabris D, Fredel MC, Henriques B. Translucent multi-layered zirconia: Sandblasting effect on optical and mechanical properties. Dent Mater 2023; 39:807-819. [PMID: 37474437 DOI: 10.1016/j.dental.2023.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/28/2023] [Accepted: 07/04/2023] [Indexed: 07/22/2023]
Abstract
OBJECTIVE The aim of this study was to evaluate the influence of the sandblasting treatment on the microstructure, optical and mechanical properties of multi-layered translucent zirconia. METHODS Samples of yttria-stabilized zirconia were prepared by stratifying four layers (L1, L2, L3 and L4) of ML-type KATANA multi-layered monolithic discs, whose surfaces were then sandblasted with alumina particles (110 µm and 0.2 MPa) in order to evaluate its effect on the presence of different crystalline phases as well as on the optical and mechanical properties of each of the four layers. The optical characterization was carried out by measuring the reflectance spectrum and colorimetric parameters by UV-Vis spectrophotometric analysis and the transmittance curves were indirectly obtained using the Kubelka-Munk model (KM). Microstructural, structural, mechanical and roughness characterizations were also performed using SEM, XRD, biaxial flexural strength B3B, and light interferometry, respectively RESULTS: According to the KM model there are different degrees of translucency between the upper and lower layers of the monolithic discs, but there was no influence of the Al2O3-sandblasting treatment on this optical property. The disk pigmentation causes greater absorption of light below 600 nm, decreasing the transmittance rate to values below 25% in this region of the spectrum. The yellowing index presented higher values for inner disk layers L3 and L4, in agreement with the highest values of the light absorption coefficient K observed for these layers. The roughness of the samples did not change significantly with the surface treatment performed and the sandblasting did not result in new crystalline phases. SEM analysis showed the presence of different grain sizes in all layers analyzed, being related to the co-occurring presence of cubic (c-ZrO2) and tetragonal (t-ZrO2) phases in similar contents (∼ 50 wt%). The Weibull statistical analysis, in turn, showed an increase in the Weibull characteristic stress value (σ0) for most layers subjected to sandblasting, except for the second layer (central region of the disk). It was also verified an increase in the value of the structural reliability of the material (m), referring to the samples of the central region of the disc (L2 and L3 layers) after sandblasting. SIGNIFICANCE The pigmentation in the disk causes a decrease of the transmittance rate to values well below 25% in the region of the spectrum 400-600 nm and the inner layers (L3 and L4) have even lower transmittance than the outer layers in this spectrum range. Although the CR index indicates variation related to the Al2O3-sandblasting treatment, the transmittance spectra of KM model show that the sandblasting did not cause a significant change in the transmittance rate of the four analyzed layers. Also, there is no significant difference in the light scattering of the different layers of the disc, either before or after Al2O3-sandblasting treatment.
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Affiliation(s)
- Luciana M Schabbach
- Special Coordination of Materials Engineering, Federal University of Santa Catarina (UFSC), Campus Blumenau, 89036-002 Blumenau, SC, Brazil; Ceramic and Composite Materials Research Group (CERMAT), Mechanical Engineering Department (EMC), Federal University of Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Bruno C Dos Santos
- Ceramic and Composite Materials Research Group (CERMAT), Mechanical Engineering Department (EMC), Federal University of Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Leticia S De Bortoli
- Special Coordination of Materials Engineering, Federal University of Santa Catarina (UFSC), Campus Blumenau, 89036-002 Blumenau, SC, Brazil; Ceramic and Composite Materials Research Group (CERMAT), Mechanical Engineering Department (EMC), Federal University of Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Douglas Fabris
- Ceramic and Composite Materials Research Group (CERMAT), Mechanical Engineering Department (EMC), Federal University of Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Marcio Celso Fredel
- Ceramic and Composite Materials Research Group (CERMAT), Mechanical Engineering Department (EMC), Federal University of Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Bruno Henriques
- Ceramic and Composite Materials Research Group (CERMAT), Mechanical Engineering Department (EMC), Federal University of Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC, Brazil; School of Dentistry (DODT), Postgraduate Program in Dentistry (PPGO), Federal University of Santa Catarina, Campus Trindade, 88040-900, Florianópolis SC, Brazil; CMEMS-UMinho, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
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Subsomboon C, Urapepon S. Effect of connector configuration on the fracture load in conventional and translucent zirconia three-unit fixed dental prostheses. J Adv Prosthodont 2023; 15:171-178. [PMID: 37662855 PMCID: PMC10471503 DOI: 10.4047/jap.2023.15.4.171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/19/2023] [Accepted: 08/10/2023] [Indexed: 09/05/2023] Open
Abstract
PURPOSE The purpose of this study was to determine the effect of the connector configuration on the fracture load in conventional and translucent zirconia of three-unit fixed dental prostheses (FDPs). MATERIALS AND METHODS Six different three-unit FDPs were prepared (n = 6) from three types of zirconia (3Y-TZP (Katana ML®), 4Y-TZP (Katana STML®), and 5Y-TZP (Katana UTML®)) in combination with two connector configurations (4 × 2.25, 3 × 3 mm). The Co-Cr master models were scanned, and the FDPs were designed and fabricated using CAD-CAM. The FDPs were cemented on the metal model and then loaded with a UTM at a crosshead speed of 1 mm/min until failure. Two-way ANOVA and Tukey's test were used for statistical analysis (α = .05). RESULTS Fracture loads of 3Y-TZP (2740.6 ± 469.2 and 2718.7 ± 339.0 N for size 4 × 2.25 mm and 3 × 3 mm, respectively) were significantly higher than those of 4Y-TZP (1868.3 ± 281.6 and 1663.6 ± 372.7 N, respectively) and 5Y-TZP (1588.0 ± 255.0 and 1559.1 ± 110.0 N, respectively) (P < .05). No significant difference was found between fracture loads of 4Y-TZP and 5Y-TZP (P > .05). The connector configuration within 9 mm2 was found to have no effect on the fracture loads on all three types of zirconia (P > .05). CONCLUSION Fracture loads of three-unit FDPs were affected by the type of zirconia. The fracture loads of conventional zirconia were higher than those of translucent zirconia. However, it was not affected by the connector configuration when the connector had a cross-sectional area of 9 mm2.
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Affiliation(s)
- Chonticha Subsomboon
- Department of Prosthodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - Somchai Urapepon
- Department of Prosthodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
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Wang L, Yu H, Hao Z, Tang W, Dou R. Investigating the effect of solid loading on microstructure, mechanical properties, and translucency of highly translucent zirconia ceramics prepared via stereolithography-based additive manufacturing. J Mech Behav Biomed Mater 2023; 144:105952. [PMID: 37311296 DOI: 10.1016/j.jmbbm.2023.105952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/31/2023] [Accepted: 05/31/2023] [Indexed: 06/15/2023]
Abstract
A study was conducted to explore the potential of 5 mol% yttria-partially stabilized zirconia (5Y-PSZ) ceramics for dental restorations, using stereolithography (SLA) printing technique. Four different solid loadings were established in the ceramic paste systems to study their effects on microstructure, mechanical properties, and translucency. The study examined the rheological behavior and photopolymerization performance of the ceramic pastes with varying solid loadings. Results showed that, an increase in powder concentration resulted in a decrease in cure depth (Cd) and penetration depth (Dp). A narrower pore size distribution was observed in the green bodies with a high solid loading, facilitating the achievement of final densification. The green and sintered densities were highest at 52 vol%, with values of 3.46 ± 0.01 g/cm3 and 6.01 ± 0.02 g/cm3, respectively. Additionally, all of the green strengths exceeded 30 MPa, with a maximum of 35.09 ± 2.02 MPa obtained at 44 vol%. The maximum flexural strength and minimum contrast ratio (CR) value of 746 ± 75 MPa and 0.40 ± 0.01 were achieved at 52 vol% after sintering. No significant differences were observed in the phase composition and hardness of the as-sintered ceramics. Though significant differences were observed in photopolymerization performance, four materials showed similar structural reliability considering Weibull modulus and characteristic strength.
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Affiliation(s)
- Li Wang
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, School of Mechanical Engineering, Jiangnan University, Wuxi, 214122, Jiangsu, China; Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
| | - Hang Yu
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, School of Mechanical Engineering, Jiangnan University, Wuxi, 214122, Jiangsu, China; Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Zongdong Hao
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, School of Mechanical Engineering, Jiangnan University, Wuxi, 214122, Jiangsu, China; Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Weizhe Tang
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, School of Mechanical Engineering, Jiangnan University, Wuxi, 214122, Jiangsu, China; Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
| | - Rui Dou
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, School of Mechanical Engineering, Jiangnan University, Wuxi, 214122, Jiangsu, China; Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
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Salah K, Sherif AH, Mandour MH, Nossair SA. Optical effect of rapid sintering protocols on different types of zirconia. J Prosthet Dent 2023; 130:253.e1-253.e7. [PMID: 37330359 DOI: 10.1016/j.prosdent.2023.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 05/07/2023] [Accepted: 05/09/2023] [Indexed: 06/19/2023]
Abstract
STATEMENT OF PROBLEM Rapid sintering protocols are available for the fabrication of zirconia restorations, but whether rapid sintering influences color or translucency is unclear. PURPOSE The purpose of this in vitro study was to investigate the effect of different rapid sintering protocols on the color and translucency of cubic and tetragonal zirconias. MATERIAL AND METHODS Sixty disk-shaped specimens of 1-mm-thick cubic (DD CubeX2) and tetragonal (DD Bio ZX2) zirconia were investigated. Specimens of each type of zirconia were divided into three groups: conventional, speed, and superspeed sintering protocols. The conventional group of each zirconia type served as the control for calculating color differences. Translucency for each group was assessed by the translucency parameter and contrast ratio. Two-way analysis of variance was used for statistical analysis of the data (α=.05). RESULTS The translucency of cubic and tetragonal zirconia decreased after speed and superspeed sintering (P<.001). Superspeed sintering resulted in a greater color change than speed sintering (P<.001). CONCLUSIONS Rapid sintering protocols produced a significant effect on the color and translucency of cubic and tetragonal zirconias.
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Affiliation(s)
- Kerolos Salah
- Former Postgraduate student, Department of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Future University, New Cairo, Egypt.
| | - Ashraf Hussein Sherif
- Professor, Department of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Future University, New Cairo, Egypt
| | - Mona H Mandour
- Professor, Department of Crown and Bridge, Faculty of Dental Medicine, Al-Azhar University, Girls' Branch, Cairo, Egypt
| | - Shereen Ahmed Nossair
- Assistant Professor, Department of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Future University, New Cairo, Egypt
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Kongkiatkamon S, Rokaya D, Kengtanyakich S, Peampring C. Current classification of zirconia in dentistry: an updated review. PeerJ 2023; 11:e15669. [PMID: 37465158 PMCID: PMC10351515 DOI: 10.7717/peerj.15669] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/09/2023] [Indexed: 07/20/2023] Open
Abstract
Zirconia, a crystalline oxide of zirconium, holds good mechanical, optical, and biological properties. The metal-free restorations, mostly consisting of all-ceramic/zirconia restorations, are becoming popular restorative materials in restorative and prosthetic dentistry choices for aesthetic and biological reasons. Dental zirconia has increased over the past years producing wide varieties of zirconia for prosthetic restorations in dentistry. At present, literature is lacking on the recent zirconia biomaterials in dentistry. Currently, no article has the latest information on the various zirconia biomaterials in dentistry. Hence, the aim of this article is to present an overview of recent dental zirconia biomaterials and tends to classify the recent zirconia biomaterials in dentistry. This article is useful for dentists, dental technicians, prosthodontists, academicians, and researchers in the field of dental zirconia.
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Affiliation(s)
- Suchada Kongkiatkamon
- Department of Prosthetic Dentistry, Faculty of Dentistry, Prince of Songkla University, Songkhla, Thailand
| | - Dinesh Rokaya
- Faculty of Dentistry, Zarqa University, Zarqa, Jordan
| | - Santiphab Kengtanyakich
- Prosthodontic Section, Department of Restorative Dentistry, Naresuan University, Phitsanulok, Thailand
| | - Chaimongkon Peampring
- Department of Prosthetic Dentistry, Faculty of Dentistry, Prince of Songkla University, Songkhla, Thailand
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Kengtanyakich S, Peampring C. Effect of Hydrothermal Degradation on Flexural Fatigue Strength of Various Cubic-Containing Translucent Zirconia. Eur J Dent 2023; 17:777-783. [PMID: 36220117 PMCID: PMC10569846 DOI: 10.1055/s-0042-1755630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
OBJECTIVE The aim of this study is to investigate the fatigue and hydrothermal degradation behavior among the cubic-containing translucent yttrium oxide stabilized tetragonal zirconia polycrystal (Y-TZP). MATERIALS AND METHODS Four groups of commercial Y-TZP (T, ST, XT, and P), containing different amount of cubic crystal, were examined. Artificial aging was accomplished by autoclaving at 122°C under 2 bar pressure for 8 hours. Fatigue simulation parameters were set using an axial 50 N load, a total of 240,000 cycles. Flexural fatigue strength was evaluated. STATISTICAL ANALYSIS Two-way analysis of variance with Tukey's honestly significant difference test was used to determine the difference in fatigue strength values between various type of zirconia materials within control and aging with a significant level of 5%. Weibull analysis was conducted on the fatigue strength data. RESULTS All groups showed the mean flexural fatigue strength had no significant difference in hydrothermally aged specimens compared with specimens without aging (p = 0.154). Group T showed significantly higher flexural fatigue strength followed by group ST, XT, and P. Group XT and P showed no significant difference in strength value (p > 0.05). Group T demonstrated a lower probability of failure than group ST, XT, and P whether with or without aging. Weibull modulus in group T and ST with aging condition was increased and higher than all the experimental groups. CONCLUSION Cubic-containing zirconia materials (group ST, XT, and P) exhibited lower flexural fatigue strength than non-cubic 3Y-TZP zirconia (group T). However, various cubic-containing translucent zirconia was assumed to have high resistance to hydrothermal degradation.
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Affiliation(s)
- Santiphab Kengtanyakich
- Department of Prosthetic Dentistry, Faculty of Dentistry, Prince of Songkla University, Songkhla, Thailand
| | - Chaimongkon Peampring
- Department of Prosthetic Dentistry, Faculty of Dentistry, Prince of Songkla University, Songkhla, Thailand
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Alshahrani AM, Lim CH, Kim J, Zhang Y. Transient thermal stresses developed during speed sintering of 3 mol% yttria-stabilized tetragonal zirconia polycrystals. Dent Mater 2023; 39:522-528. [PMID: 37045719 PMCID: PMC10168597 DOI: 10.1016/j.dental.2023.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 04/05/2023] [Indexed: 04/14/2023]
Abstract
OBJECTIVES To investigate transient thermal stresses that developed in 3Y-TZP green compacts during speed sintering. METHODS A total of 312 disc-shaped green compacts (Ø17.1 ×1, 1.5, 2, 2.5, 3 mm) were cold-isostatically pressed from 3Y-TZP powder (Zpex, Tosoh Corp.) for speed sintering studies as well as compositional analysis and biaxial flexural strength measurements (both at room temperature and following heating at 90 °C/min to 500 °C). Flexural strength was determined using the piston-on-3-ball method. Phase assemblies were analyzed using the X-ray diffraction method. Effects of heating/cooling rates on transient stresses were investigated by conducting definitive sintering studies to determine the threshold for fracture. Finite element analysis (FEA) was used to validate the experimental findings using measured thermomechanical properties. RESULTS The bulk and relative density of the green compact were 2.95 ± 0.03 g/cm3 and 48.52% ± 0.45%. The flexural strength was drastically decreased from 10.3 ± 0.4 MPa to 1.09 ± 0.07 MPa following heating at 90 °C/min to 500 °C. The monoclinic and tetragonal contents were 54.9% and 45.1%, respectively. The threshold for fracture was located at 500 °C during the first heating stage with a 90 °C/min heating rate in specimens of 2.5 mm thickness or greater. No fractures occurred in the second heating stage and cooling phase. The FEA estimated that the principal transient tensile stress was ∼1.14 MPa at 500 °C during the heating phase, which exceeded the corresponding flexural strength (1.09 ± 0.07 MPa). SIGNIFICANCE Advanced FEA methods are an accurate and efficient tool to analyze the history of transient stresses during sintering of ceramic dental restorations.
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Affiliation(s)
- Abdulaziz M Alshahrani
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Restorative Dental Sciences, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Chek Hai Lim
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jeongho Kim
- Department of Civil and Environmental Engineering, University of Connecticut, 261 Glenbrook Rd, U-3037, Storrs, CT 06269, USA
| | - Yu Zhang
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Adabo GL, Longhini D, Baldochi MR, Bergamo ETP, Bonfante EA. Reliability and lifetime of lithium disilicate, 3Y-TZP, and 5Y-TZP zirconia crowns with different occlusal thicknesses. Clin Oral Investig 2023:10.1007/s00784-023-05001-6. [PMID: 37022529 DOI: 10.1007/s00784-023-05001-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/28/2023] [Indexed: 04/07/2023]
Abstract
OBJECTIVES To assess the probability of survival of crowns made with a 3Y-TZP, a 5Y-TZP, and a lithium disilicate. MATERIALS AND METHODS CAD-CAM premolar crowns with occlusal thicknesses of 1.0 mm or 1.5 mm and cemented on a metal dye. Step-stress accelerated life testing (SSALT) was performed to access the use level probability Weibull curves and reliability were calculated for the completion of a mission of 100,000 cycles at 300 to 1200 N. RESULTS All ceramics showed a high probability of survival (87-99%) at 300 N, irrespective of thickness. 3Y-TZP shows no significant decrease in the probability of survival up to 1200 N (83-96%). Lithium disilicate presented lower reliability than zirconia under the 600 N mission. 5Y-TZP showed lower reliability than 3Y-TZP at 1200 N. There was no significant difference in the Weibull modulus (3.23-7.12). 3Y-TZP had the highest characteristic strength (2483-2972 N), followed by 5Y-TZP (1512-1547 N) and lithium disilicate (971-1154 N). CONCLUSION Zirconia ceramics have a high probability of survival (up to 900 N-load), while lithium disilicate survives up to 300 N load only, irrespective of the thickness (1.0 mm or 1.5 mm). CLINICAL RELEVANCE The probability of survival of posterior crowns made with zirconia ceramics resists extreme loads while glass ceramics resist normal chewing loads. In addition, crowns with thinner occlusal face showed sufficient mechanical behavior.
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Grants
- 2016/09640-0, 2012/19078-7, 2021/06730-7, EMU 2016/18818-8, 2019/08693-1 Fundação de Amparo à Pesquisa do Estado de São Paulo
- 2016/09640-0, 2012/19078-7, 2021/06730-7, EMU 2016/18818-8, 2019/08693-1 Fundação de Amparo à Pesquisa do Estado de São Paulo
- 2016/09640-0, 2012/19078-7, 2021/06730-7, EMU 2016/18818-8, 2019/08693-1 Fundação de Amparo à Pesquisa do Estado de São Paulo
- Finance Code 001 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
- Finance Code 001 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
- 307255/2021-2 Conselho Nacional de Desenvolvimento Científico e Tecnológico
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Affiliation(s)
- Gelson Luis Adabo
- School of Dentistry, Sao Paulo State University (Unesp), Araraquara, Sao Paulo, Brazil.
| | - Diogo Longhini
- School of Dentistry, Sao Paulo State University (Unesp), Araraquara, Sao Paulo, Brazil
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Darwich RA, Awad M, Abou Neel EA. Effect of Different Decontamination Methods on Fracture Resistance, Microstructure, and Surface Roughness of Zirconia Restorations-In Vitro Study. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2356. [PMID: 36984236 PMCID: PMC10056380 DOI: 10.3390/ma16062356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/25/2023] [Accepted: 03/10/2023] [Indexed: 06/18/2023]
Abstract
This study aimed to evaluate the effect of seven different decontamination methods (water, ZirCleanTM, 37% phosphoric acid, 9.5% hydrofluoric acid, Al2O3 sandblasting, low-speed dental stone, and high-speed dental stone) on the fracture resistance, microstructure, and surface roughness of monolithic and multilayered zirconia. The as-received and sandblasted zirconia was used as a control. One-way ANOVA and t-test were performed. As-received monolithic zirconia was stronger (856 ± 94 MPa) than multilayered zirconia (348.4 ± 63 MPa). Only phosphoric acid (865 ± 141 MPa) and low-speed dental stone (959 ± 116 MPa) significantly increased the flexural strength of sandblasted monolithic zirconia (854 ± 99 MPa), but all tested decontamination methods except phosphoric acid (307 ± 57 MPa) and Al2O3 (322 ± 69 MPa) significantly increased the flexural strength of sandblasted multilayered zirconia (325 ± 74 MPa). Different decontamination methods did not significantly affect the flexural modulus, but introduced irregularities in the crystal as well as deep surface flaws in both types of zirconia. The surface of sandblasted monolithic zirconia is more resistant to change than multilayered zirconia. Among different decontamination methods, a low-speed dental stone could be beneficial as it significantly increased the surface roughness and fracture resistance of both types of zirconia.
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Affiliation(s)
- Rama A. Darwich
- Preventive and Restorative Dentistry Department, College of Dental Medicine, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates
| | - Manal Awad
- Preventive and Restorative Dentistry Department, College of Dental Medicine, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates
| | - Ensanya A. Abou Neel
- Preventive and Restorative Dentistry Department, College of Dental Medicine, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates
- UCL Eastman Dental Institute, Biomaterials & Tissue Engineering, Royal Free Hospital, Rowland and Hill Street, London NW3 2QG, UK
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Dolve E, Ben-Izhack G, Meirowitz A, Erel H, Rosner O, Biadsee A, Lugassy D, Shely A. The Light Reflection Changes of Monolithic Zirconia and Lithium Disilicate after Using Two External Staining Kits following by Thermocycling. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2057. [PMID: 36903172 PMCID: PMC10004587 DOI: 10.3390/ma16052057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 02/24/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND The purpose of the study was to evaluate the changes of light reflection% on two materials (monolithic zirconia and lithium disilicate) after using two external staining kits following by thermocycling. METHODS Specimens were sectioned from monolithic zirconia (n = 60) and lithium disilicate (n = 60) then divided into six groups (n = 20). Two different types of external staining kits were used and applied to the specimens. The light reflection% was measured before staining, after staining and after thermocycling using a spectrophotometer. RESULTS The light reflection% of zirconia was significantly higher compared to lithium disilicate at the beginning of the study (p = 0.005), after staining with kit 1 (p = 0.005) and kit 2 (p = 0.005) and after thermocycling (p = 0.005). For both materials, the light reflection% was lower after staining with Kit 1 compared to kit 2 (p < 0.043). After thermocycling, the light reflection% of lithium disilicate increased (p = 0.027) and was unchanged with Zirconia (p = 0.527). CONCLUSIONS There is a difference between the materials regarding light reflection% as the monolithic zirconia showed higher light reflection% comparing lithium disilicate throughout the entire experiment. For lithium disilicate, we recommend using kit 1 as we found that, after thermocycling, the light reflection% of kit 2 was increased.
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Kim BK, Yun JH, Jung WK, Lim CH, Zhang Y, Kim DK. Mitigating grain growth in fully stabilized zirconia via a two-step sintering strategy for esthetic dental restorations. INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY 2023; 20:856-868. [PMID: 39149536 PMCID: PMC11326489 DOI: 10.1111/ijac.14216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/04/2022] [Indexed: 08/17/2024]
Abstract
Overall, 8-mol% yttria-stabilized zirconia (8YSZ), unlike 3YSZ, is optically transparent and stable against low-temperature degradation but has insufficient mechanical properties due to its large grain size. The influence of the grain size of 8YSZ on mechanical properties was investigated to develop an 8YSZ suitable for dental restoration. Modulation of the grain size and relative density was achieved via a two-step sintering (TSS) process, and the corresponding kinetic window was established. The conditions of TSS employed herein yielded a relative density of more than 99% while maintaining a small grain size of 0.75 μm. On the other hand, the highest biaxial strength and the highest total transmittance attained were 833 MPa and 34.6% (1-mm-thick, 39.1% for a 0.5-mm thick sample) in the TSS 8YSZ with a grain size of 1.25 μm. These results suggest that strength has improved only when grain size reduction and increased relative density are achieved at the same time. The results demonstrate that the ceramic processing method has a significant effect on the mechanical and optical properties of 8YSZ needed for dental restoration and provide a new insight that contrasts previous studies focused on the starting material.
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Affiliation(s)
- Boo Kyung Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jong Hyuk Yun
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Wook Ki Jung
- Agency for Defense Development, Daejeon, Republic of Korea
| | - Chek Hai Lim
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu Zhang
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Do Kyung Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
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de Castro EF, Fronza BM, Soto-Montero J, Giannini M, Dos-Santos-Dias CT, Price RB. Effect of thickness of CAD/CAM materials on light transmission and resin cement polymerization using a blue light-emitting diode light-curing unit. J ESTHET RESTOR DENT 2023; 35:368-380. [PMID: 35894446 DOI: 10.1111/jerd.12946] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 07/05/2022] [Accepted: 07/11/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Evaluate the effect of thickness of high-translucency (HT) CAD/CAM materials on irradiance and beam profile from a blue light-emitting diode light-curing unit (LCU) and on the degree of conversion (DC) and maximum polymerization rate (Rpmax ) of a light-cured resin cement (LCC). MATERIAL AND METHODS The direct output from the LCU, the light transmission and irradiance ratio (IR) through one conventional composite and nine HT CAD/CAM materials (0.5, 1.0, 1.5, or 2.0-mm thick; n = 5) were measured with a integrating sphere coupled to a spectrometer. The light beam was assessed with a beam profiler camera. The DC at 600 s and the Rpmax of one LCC was determined using a Fourier transform infrared spectrometer (n = 5). Data were analyzed by ANOVA followed by Tukey's tests, and Dunnett's test was also used for irradiance data (α = 0.05). RESULTS A significant decrease in irradiance through all materials occurred as thickness increased. Thin CAD/CAM materials improved light homogeneity, which decreased with the increase in thickness. The DC of the LCC directly exposed to light was the same as when exposed to 45%, 25%, 15%, or 5% IRs. Rpmax decreased with the decrease in IR. CONCLUSIONS Although the HT CAD/CAM materials reduced the irradiance from the LCU, minor effects were observed in the LCC's DC. CLINICAL SIGNIFICANCE Despite the light attenuation of blue light through different CAD/CAM materials that were up to 2-mm thick, the degree of conversion of one brand of light-cured resin cement was clinically acceptable when the LCU was used for 30 s.
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Affiliation(s)
- Eduardo Fernandes de Castro
- Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil
| | - Bruna Marin Fronza
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Jorge Soto-Montero
- Department of Restorative Dentistry, School of Dentistry, Universidad de Costa Rica, San Pedro, Costa Rica
| | - Marcelo Giannini
- Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil
| | - Carlos Tadeu Dos-Santos-Dias
- Department of Exact Sciences, College of Agriculture, "Luiz de Queiroz"/University of São Paulo, Piracicaba, Brazil
| | - Richard Bengt Price
- Department of Dental Clinical Sciences, School of Dentistry, Dalhousie University, Halifax, Canada
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Barile G, Capodiferro S, Muci G, Carnevale A, Albanese G, Rapone B, Corsalini M. Clinical Outcomes of Monolithic Zirconia Crowns on Posterior Natural Abutments Performed by Final Year Dental Medicine Students: A Prospective Study with a 5-Year Follow-Up. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:2943. [PMID: 36833639 PMCID: PMC9966316 DOI: 10.3390/ijerph20042943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/03/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
The conventional metal-ceramic is still considered the gold standard in fixed prosthetics especially in terms of longevity. Among alternative materials used, Monolithic Zirconia has shown the capability to reconcile excellent biomechanical properties with acceptable aesthetic performance and to overcome several inconveniences related to veneer restorations. This study aims to clinically evaluate Monolithic Zirconia prosthetic crowns on natural abutments in the posterior sectors, performed by final-year dental medicine students (undoubtedly with less experience in the management of such material) by the standardized California Dental Association score system evaluation, to better understand the viability of Monolithic Zirconia. This prospective study was carried out at the Dental School of the University of Bari "Aldo Moro", Italy. Prosthetic rehabilitation included single crowns or a short pontic prosthesis with maximum one intermediate. Final-year dental students performed tooth reduction under the supervision of three expert tutors. The California Dental Association systematics (based on color, surface, anatomical shape, and marginal integrity) were adopted to evaluate the prosthetic maintenance status over time. Annual follow-up visits were re-evaluated by the same parameters each year. Univariate logistic regression analysis was performed to evaluate outcomes and the Kaplan-Meier plot to report survival. The sample consists of 40 crowns performed on 31 patients, 15 males (48.4%) and 16 females (51.6%) with an average age of 59.3 years. The clinical cases subjected to experimental study were found to be "Excellent" (1a/2a/3a/4a) in 34 cases (85%), "Acceptable" in 4 cases (10%), and "To be re-done" in 2 cases (failures) (5%). Our conclusive data support the predictability of Monolithic Zirconia restorations on natural posterior abutments at a long-term follow-up of five years, even when performed by less-experienced clinicians.
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Affiliation(s)
- Giuseppe Barile
- Department of Interdisciplinary Medicine, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Saverio Capodiferro
- Department of Interdisciplinary Medicine, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Giovannino Muci
- Dental School, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | | | - Giovanni Albanese
- Department of Interdisciplinary Medicine, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Biagio Rapone
- Department of Interdisciplinary Medicine, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Massimo Corsalini
- Department of Interdisciplinary Medicine, University of Bari “Aldo Moro”, 70124 Bari, Italy
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Toma FR, Porojan SD, Vasiliu RD, Porojan L. The Effect of Polishing, Glazing, and Aging on Optical Characteristics of Multi-Layered Dental Zirconia with Different Degrees of Translucency. J Funct Biomater 2023; 14:jfb14020068. [PMID: 36826868 PMCID: PMC9967825 DOI: 10.3390/jfb14020068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/14/2023] [Accepted: 01/24/2023] [Indexed: 02/01/2023] Open
Abstract
(1) Background: Considering that the appearance of a dental material is an important factor that contributes to the success of prosthetic restorations. The purpose of this study is to investigate the optical properties and color changes among the layers of three commercial zirconias, to compare the aspect of the polished and glazed surfaces before and after aging and to evaluate the effects of hydrothermal degradation on their aesthetics. (2) Methods: Forty-eight plate-shaped samples were sectioned from presintered blocks of each multilayer translucent zirconia with different Yttrium content: Ceramill Zolid fx ML (5 mol%) = CeZ, STML (4 mol%) = STM, IPS e.maxZirCAD CEREC/in Lab MT Multi (4 mol% + 5 mol%) = IPZ. The samples were sintered according to the recommendation of each manufacturer, and half (24) of them were polished and the other half (24) glazed on one of the surfaces. Each type was equally divided into one control and one aging group, and, for each material, this resulted in four groups (n = 12): polished-control, polished-autoclaved glazed-control, and glazed-autoclaved. The artificial aging was carried out with an autoclave and distilled water at 134 °C, 0.2 MPa for 1 h, and for optical parameters (TP, CR, OP) and color change (ΔE*) measurements on a black and white background in a CIE L*a*b* color system, a spectrophotometer was used. The specimens were evaluated in incisal, cervical, and medium areas on polished and glazed samples before and after the aging stage. Statistical analysis was achieved with a two-way ANOVA test, the unpaired t-test, and the paired t-test. (3) Results: Before and after aging, the mean TP values for polished samples were higher than the glazed ones. After aging, the mean TP values increased for all groups (except polished CeZ), and significant differences were reported for polished STM, IPZ. After LTD, the opalescence registered an increase for almost all groups (except polished CeZ, polished and glazed IPZ-medium area), and significant differences were reported for almost all groups (except STM-incisal, IPZ-cervical, medium areas). The levels of color change were between extremely slight to perceivable. (4) Conclusions: Optical properties of the selected multilayer zirconia were influenced by polishing and glazing as surface treatment and affected by artificial aging (CeZ the least); perceivable color changes for polished STM, IPZ were detected.
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Affiliation(s)
- Flavia Roxana Toma
- Department of Dental Prostheses Technology (Dental Technology), Center for Advanced Technologies in Dental Prosthodontics, Faculty of Dental Medicine, “Victor Babeș” University of Medicine and Pharmacy Timișoara, Eftimie Murgu Sq. No. 2, 300041 Timisoara, Romania
| | - Sorin Daniel Porojan
- Department of Oral Rehabilitation (Dental Technology), Center for Advanced Technologies in Dental Prosthodontics, Faculty of Dental Medicine, “Victor Babeș” University of Medicine and Pharmacy Timișoara, Eftimie Murgu Sq. No. 2, 300041 Timisoara, Romania
| | - Roxana Diana Vasiliu
- Department of Dental Prostheses Technology (Dental Technology), Center for Advanced Technologies in Dental Prosthodontics, Faculty of Dental Medicine, “Victor Babeș” University of Medicine and Pharmacy Timișoara, Eftimie Murgu Sq. No. 2, 300041 Timisoara, Romania
| | - Liliana Porojan
- Department of Dental Prostheses Technology (Dental Technology), Center for Advanced Technologies in Dental Prosthodontics, Faculty of Dental Medicine, “Victor Babeș” University of Medicine and Pharmacy Timișoara, Eftimie Murgu Sq. No. 2, 300041 Timisoara, Romania
- Correspondence:
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