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Fahimi MA, Azarbayejani S, Mohammadi-Bassir M. Comparing the effect of two polishing systems on surface roughness of feldspathic, lithium disilicate, and translucent zirconia ceramics after orthodontic bracket debonding: An in vitro study. Int Orthod 2024; 22:100923. [PMID: 39332084 DOI: 10.1016/j.ortho.2024.100923] [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: 06/28/2024] [Revised: 09/03/2024] [Accepted: 09/06/2024] [Indexed: 09/29/2024]
Abstract
INTRODUCTION Debonding of orthodontic brackets on ceramic restorations leave a rough surface which should be efficiently polished. In this study the effect of two diamond polishing systems (DPS), namely Optra Fine® (OF) and Diapol Twist® (DT) on surface roughness (SR) of feldspathic (F), lithium disilicate (LD), and translucent zirconia (TZ) ceramics assessed after bracket debonding. MATERIALS AND METHODS Ninety disc-shaped specimens fabricated from F, LD, and TZ ceramics and glazed (Gl). Ten glazed specimens of 3 ceramic types served as control (C) groups (n=30). Other 60 specimens were deglazed, and after specific surface preparation according to ceramic type, upper central incisor brackets were bonded. After debonding, the remaining adhesive composite removed with tungsten carbide bur and specimens randomly assigned into 6 groups. The nine experimental groups defined as: Glazed F specimens (C), Deglazed F specimens polished with DT, Deglazed F specimens polished with OF, Glazed LD specimens (C), Deglazed LD specimens polished with DT, Deglazed LD specimens polished with OF, Glazed TZ specimens (C), Deglazed TZ specimens polished with DT, Deglazed TZ specimens polished with OF. The SR assessed quantitatively by profilometry (Ra and Rz parameter) and qualitatively by scanning electron microscopy (SEM). Quantitative data were statistically analysed using Kolmogorov-Smirnov test, two-way ANOVA and Tukey post-hoc test (α=0.05). RESULTS No significant difference found in SR of three glazed ceramic types (P=0.293 for Ra and P=0.473 for Rz). There was no significant difference of Ra between polished and glazed groups (P>0.05). However, difference in Rz was significant (P<0.05), and only TZ specimens could reach to the level of smoothness caused by glazing. CONCLUSIONS Both diamond polishing systems can efficiently reduce the surface roughness, despite of ceramic type. Optra Fine® system showed a superior performance than Diapol Twist® without significant difference. LIMITATIONS In this study only one brand of each ceramic type was investigated. This study was approved by Ethical Review Committee (IR.IAU.KHUISF.REC.1401.156).
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Affiliation(s)
- Mohammad Amin Fahimi
- Department of Orthodontics, Dental School, Isfahan (Khorasgan) Branch, Islamic Azad University, Tehran, Iran
| | - Saeed Azarbayejani
- Department of Orthodontics, Dental School, Isfahan (Khorasgan) Branch, Islamic Azad University, Tehran, Iran
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Mayinger F, Ender A, Strickstrock M, Elsayed A, Nassary Zadeh P, Zimmermann M, Stawarczyk B. Impact of the sintering parameters on the grain size, crystal phases, translucency, biaxial flexural strength, and fracture load of zirconia materials. J Mech Behav Biomed Mater 2024; 155:106580. [PMID: 38759588 DOI: 10.1016/j.jmbbm.2024.106580] [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: 03/12/2024] [Revised: 05/06/2024] [Accepted: 05/10/2024] [Indexed: 05/19/2024]
Abstract
OBJECTIVES To investigate the influence of the zirconia and sintering parameters on the optical and mechanical properties. METHODS Three zirconia materials (3/4Y-TZP, 4Y-TZP, 3Y-TZP) were high-speed (HSS), speed (SS) or conventionally (CS) sintered. Disc-shaped specimens nested in 4 vertical layers of the blank were examined for grain size (GS), crystal phases (c/t'/t/m-phase), translucency (T), and biaxial flexural strength. Fracture load (FL) of three-unit fixed dental prostheses was determined initially and after thermomechanical aging. Fracture types were classified, and data statistically analyzed. RESULTS 4Y-TZP showed a higher amount of c + t'-phase and lower amount of t-phase, and higher optical and lower mechanical properties than 3Y-TZP. In all materials, T declined from Layer 1 to 4. 3/4Y-TZP showed the highest FL, followed by 3Y-TZP, while 4Y-TZP showed the lowest. In 4Y-TZP, the sintering parameters exercised a direct impact on GS and T, while mechanical properties were largely unaffected. The sintering parameters showed a varying influence on 3Y-TZP. Thermomechanical aging resulted in comparable or higher FL. CONCLUSION 3/4Y-TZP presenting the highest FL underscores the principle of using strength-gradient multi-layer blanks to profit from high optical properties in the incisal area, while ensuring high mechanical properties in the lower areas subject to tensile forces. With all groups exceeding maximum bite forces, the examined three-unit FDPs showed promising long-term mechanical properties.
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Affiliation(s)
- Felicitas Mayinger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany.
| | - Andreas Ender
- Division of Computerized Restorative Dentistry, Clinic of Conservative and Preventive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
| | - Monika Strickstrock
- Faculty of Engineering and Computer Science, Material Science and Analysis, University of Applied Sciences Osnabrück, Albrechtstraße 30, 49076, Osnabrück, Germany
| | - Adham Elsayed
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Parissa Nassary Zadeh
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Marcus Zimmermann
- Division of Computerized Restorative Dentistry, Clinic of Conservative and Preventive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
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Salama AA, Shehab KA, Bushra SS, Hamza FS. The effect of aging on the translucency of contemporary zirconia generations: in-vitro study. BMC Oral Health 2024; 24:744. [PMID: 38937719 PMCID: PMC11212148 DOI: 10.1186/s12903-024-04465-6] [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: 11/28/2023] [Accepted: 06/07/2024] [Indexed: 06/29/2024] Open
Abstract
BACKGROUND The translucency of different zirconia generations at each time point after thermocycling aging is still lacking. METHODS Four zirconia materials were used with a total of 60 samples produced from monolithic third generation (5Y) 5 mol% yttria-stabilized zirconia polycrystalline ceramic and fourth generation zirconia (4Y) 4 mol% yttria-stabilized zirconia polycrystalline ceramic, represented by [group1:[CM-5Y] Ceramill Zolid fx (3rd generation zirconia) (Amann Girrbach, Koblach, Austria), group 2:[CM-4Y] Ceramill Zolid HT + (4th generation zirconia) (Amann Girrbach, Koblach, Austria), group 3:[CC-5Y] Cercon XT/ML (Dentsply Sirona, Germany) (3rd generation), and group 4:[CC-4Y] Cercon HT/ML (Dentsply Sirona, Germany) (4th generation)]. The L*a*b* figures were measured by using a spectrophotometer at baseline and after 10,000, 30,000, and 50,000 cycles of thermocycling. At each interval, the translucency of the samples was estimated by using the translucency formula CIEDE2000. The Scheffe post-hoc compared differences among each of the four materials. The Repeated measures ANOVA tested the differences between the materials at each of the different thermocycling intervals (p < .001). Data analyses were evaluated at a significance level of p < .05 (CI 95%). RESULTS Two-way ANOVA revealed that at baseline the third and fourth generation's zirconia showed statistically significant differences in translucency (P < .001). Translucency values at baseline and after thermocycling exhibited statistically significant changes (p = .003). At each of the time interval; CM-4Y had the highest translucency values followed by CM-5Y, CC-4Y and CC-5Y had the least translucency values. CONCLUSIONS The third and fourth generations of zirconia displayed different translucencies. Thermocycling affected the translucency of both third and fourth generations of zirconia. At each of the time intervals group 2:[CM-4Y] had the highest TP followed by group1:[CM-5Y], while, group 3:[CC-5Y] and group 4:[CC-4Y] had the least TP.
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Affiliation(s)
- Aya A Salama
- Department of Fixed Prosthodontics, October University for Modern Sciences and Arts, Giza, Egypt.
| | - Karim A Shehab
- Lecturer of Orthodontics, October University for Modern Sciences and Arts, Giza, Egypt
| | - Sherif Samir Bushra
- Department of Fixed Prosthodontics, October University for Modern Sciences and Arts, Giza, Egypt
| | - Faisal Safwat Hamza
- Department of Fixed Prosthodontics, October University for Modern Sciences and Arts, Giza, Egypt
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Kang CM, Hsu WC, Chen MS, Wu HY, Mine Y, Peng TY. Fracture characteristics and translucency of multilayer monolithic zirconia crowns of various thicknesses. J Dent 2024; 145:105023. [PMID: 38670331 DOI: 10.1016/j.jdent.2024.105023] [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: 02/08/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 04/28/2024] Open
Abstract
OBJECTIVES Multilayer monolithic zirconia (M-Zr) crowns can be engineered to achieve gradational translucency and color intensity. However, this modification may compromise the mechanical strength, raising concerns regarding the ability of M-Zr crowns to withstand occlusal stresses. The effects of M-Zr crown thickness on translucency and ability to endure occlusal forces were investigated at different tooth positions (incisors, premolars, and molars). The objective was to determine the minimal thickness of M-Zr crowns used in tooth preparation to meet aesthetic and functional demands. METHODS M-Zr samples (Vita A1) with four thicknesses (0.5, 1.0, 1.5, and 2.0 mm) were prepared and subjected to translucency testing using a digital colorimeter by 3-third and 9-square division methods. Crown-shaped M-Zr samples with three thicknesses (1.0, 1.5, and 2.0 mm) and three tooth positions (incisor, premolar, and molar) were digitally designed, and 2.0 mm metal abutments were fabricated. The samples were bonded to the abutments; their fracture characteristics were evaluated using a universal testing machine, and their fracture surfaces examined using an optical microscope. Statistical analyses included the Shapiro-Wilk test, Pearson correlation, and one-way and two-way ANOVA with a post hoc Tukey HSD test (α = 0.05). RESULTS Color analysis results revealed a significant negative correlation between thickness and translucency (r < -0.96, P < 0.01), with the highest values in the incisal region. Cross-sectional profiles confirmed the uniform thickness and morphology of the digitally designed M-Zr crowns. The results of fracture strength analysis showed position-dependent variability, a strong positive correlation with thickness (r > 0.96, P < 0.01), and fracture strengths consistently exceeding 1200 N across all tooth positions. Fracture patterns indicated that thinner crowns at the incisors and molars were more prone to cracking, whereas those at the premolars demonstrated significantly higher strength (4872.51 N, P < 0.05), only with crack or even no fracture occurring at 2.0 mm. CONCLUSIONS Thickness significantly influenced both the translucency and fracture strength of M-Zr, with the tooth position playing an additional role, albeit to a lesser extent. Although thinner crowns exhibited lower strength at each tooth position, even at a thickness of 1.0 mm, fracture strength exceeding 1200 N was maintained, surpassing the typical occlusal forces. Thus, it can be asserted that M-Zr crowns with a minimum thickness of 1.0 mm can meet both aesthetic and functional requirements.
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Affiliation(s)
- Chien-Ming Kang
- Huayi Dental Laboratory, Taipei, Taiwan; School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wen-Chieh Hsu
- School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Oral Hygiene, Hsin Sheng Junior College of Medical Care and Management, Taoyuan, Taiwan; Research Center of Precision Biomedical Implants, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - May-Show Chen
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan; Division of Prosthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan
| | - Hsuan-Yu Wu
- School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yuichi Mine
- Department of Medical Systems Engineering, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Project Research Center for Integrating Digital Dentistry, Hiroshima University, Hiroshima, Japan
| | - Tzu-Yu Peng
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
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Juntavee N, Juntavee A, Chansathien O, Prasertcharoensuk N, Leesuraplanon B. Flexural Strength of Different Monolithic Computer-Assisted Design and Computer-Assisted Manufacturing Ceramic Materials Upon Accelerated Aging. Eur J Dent 2024. [PMID: 38744328 DOI: 10.1055/s-0044-1785185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024] Open
Abstract
OBJECTIVES The durability of ceramic is crucial, which is probably influenced by aging. This study evaluated the effect of aging on flexural strength of different ceramics. MATERIALS AND METHODS One-hundred twenty ceramic discs (Ø 12 mm, 1.5 mm thickness) were prepared from zirconia-reinforced lithium silicate (ZLS, C), lithium disilicate (LS2, E), precolored yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP, Ip), and customized color Y-TZP (Ic). Samples were randomly divided into two groups for accelerated aging (A) between 5 and 55°C water baths, 30-second immersing time each, for 10,000 cycles, and nonaged group (N), serving as control. Biaxial flexural strength (σ) was evaluated utilizing the piston-on-three-balls at 0.5 mm/min speed. Analysis of variance and Tukey comparisons were determined for significant differences (α = 0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristic strength (σo). Microstructures were evaluated with scanning electron microscopy and X-ray diffraction (XRD). RESULTS The highest σ and σo were seen for IcN, followed by IcA, IpN, IpA, EN, CA, CN, and EA, respectively. CN showed the highest m, while EA showed the lowest m. Significant differences of σ for each ceramic were indicated (p < 0.05). Aging caused a significant difference in σ (p < 0.05). XRD showed t→m phase transformation of Ip and Ic after aging. CONCLUSION Aging affected strength of ceramics. Comparable strength between LS2 and ZLS was evidenced, but both were less strength than Y-TZP either aging or non-aging. Comparable strength between precolored Y-TZP and customized color Y-TZP was indicated. Better resisting aging deterioration of Y-TZP than LS2 and ZLS is suggested for fabrication restorative reconstruction.
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Affiliation(s)
- 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
| | - Orapun Chansathien
- Division of Biomaterials and Prosthodontics Research, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Natcha Prasertcharoensuk
- Division of Biomaterials and Prosthodontics Research, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Boonsita Leesuraplanon
- Division of Biomaterials and Prosthodontics Research, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
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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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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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Molinero-Mourelle P, Abou-Ayash S, Brägger U, Schimmel M, Özcan M, Yilmaz B, Buser R, Al-Haj Husain N. Load bearing capacity of 3-unit screw-retained implant-supported fixed dental prostheses with a mesial and distal cantilever on a single implant: A comparative in vitro study. J Mech Behav Biomed Mater 2024; 151:106395. [PMID: 38244420 DOI: 10.1016/j.jmbbm.2024.106395] [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: 10/04/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/22/2024]
Abstract
OBJECTIVES To assess the mechanical durability of monolithic zirconia implant-supported fixed dental prostheses (iFDP) design on one implant, with a distal and a mesial extension cantilever bonded to a titanium base compared to established designs on two implants. MATERIALS AND METHODS Roxolid Tissue level (TL), and tissue level x (TLX) implants were used to manufacture screw-retained 3-unit iFDPs (n = 60, n = 10 per group), with following configurations (X: Cantilever; I: Implant, T: Test group, C: Control group): T1: X-I-X (TL); T2: X-I-X (TLX); T3: I-I-X (TL); T4: I-I-X (TLX); C1: I-X-I (TL); C2: I-X-I (TLX). The iFDPs were thermomechanically aged and subsequently loaded until fracture using a universal testing machine. The failure load at first crack (Finitial) and at catastrophic fracture (Fmax) were measured and statistical evaluation was performed using two-way ANOVA and Tukey's post-hoc tests. RESULTS The mean values ranged between 190 ± 73 and 510 ± 459 N for Finitial groups, and between 468 ± 76 and 1579 ± 249 N for Fmax, respectively. Regarding Finitial, neither the implant type, nor the iFDP configuration significantly influenced measured failure loads (all p > 0.05). The choice of implant type did not show any significant effect (p > 0.05), while reconstruction design significantly affected Fmax data (I-I-Xa < X-I-Xb < I-X-Ic) (p < 0.05). The mesial and distal extension groups (X-I-X) showed fractures only at the cantilever extension site, while the distal extension group (I-I-X) showed one abutment and one connector fracture at the implant/reconstruction interface. CONCLUSION Results suggest that iFDPs with I-X-I design can be recommended regardless of tested implant type followed by the mesial and distal extension design on one implant abutment (X-I-X).
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Affiliation(s)
- Pedro Molinero-Mourelle
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Switzerland
| | - Samir Abou-Ayash
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Switzerland
| | - Urs Brägger
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Switzerland
| | - Martin Schimmel
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Switzerland; Division of Gerodontology and Removable Prosthodontics, University Clinics of Dental Medicine, University of Geneva, Switzerland
| | - Mutlu Özcan
- Clinic of Masticatory Disorders and Dental Biomaterials, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Burak Yilmaz
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Switzerland; Department of Restorative, Preventive and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland; Division of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, OH, USA
| | - Ramona Buser
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Switzerland
| | - Nadin Al-Haj Husain
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Switzerland; Clinic of Masticatory Disorders and Dental Biomaterials, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
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Hajhamid B, Bozec L, Tenenbaum H, De Souza G, Somogyi-Ganss E. Effect of artificial aging on optical properties and crystalline structure of high-translucency zirconia. J Prosthodont 2024; 33:61-69. [PMID: 36641491 DOI: 10.1111/jopr.13648] [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: 06/27/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/16/2023] Open
Abstract
PURPOSE To investigate the effect of different in vitro aging protocols on the optical properties and crystalline structure of high-translucency (HT) zirconia. MATERIALS AND METHODS Thirty-six specimens of HT and extra-high translucency (XT) zirconia were divided into three groups: control (CO)-no treatment; hydrothermal aging (HA)-autoclave aging for 12.5 h at 134°C, 2 bar; clinically related aging (CRA)-aging in the chewing simulator for 1.2 million cycles, followed by 50,000 thermocycles (5-55°C) and immersion in HCl (pH 1.2) for 15 h. Optical properties, crystalline structure, and surface roughness were analyzed and compared using analysis of variance (5% significance level). RESULTS There was no statistically significant effect of aging on translucency (p = 0.10), but CRA promoted the development of a high contrast ratio (p = 0.03). Aging did not cause significant color changes for HT (p = 0.65) or XT (p = 0.36). The proportion of monoclinic crystals increased to 40% for HT-zirconia after HA and 5% after CRA. No monoclinic crystals were detected for XT groups. There was no effect of aging on surface roughness (p = 0.77). CONCLUSIONS Although hydrothermal aging has been widely used to verify zirconia crystalline stability, it did not generate an effect similar to clinically related aging on the optical properties and crystalline structure of zirconia. HA affected the crystalline structure of HT-zirconia, and CRA compromised the optical properties of XT zirconia.
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Affiliation(s)
- Beshr Hajhamid
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Laurent Bozec
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Howard Tenenbaum
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Grace De Souza
- Department of Comprehensive Dentistry, School of Dentistry, University of Louisville, Louisville, Kentucky, USA
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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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Liu H, Inokoshi M, Xu K, Tonprasong W, Minakuchi S, Van Meerbeek B, Vleugels J, Zhang F. Does speed-sintering affect the optical and mechanical properties of yttria-stabilized zirconia? A systematic review and meta-analysis of in-vitro studies. JAPANESE DENTAL SCIENCE REVIEW 2023; 59:312-328. [PMID: 37705876 PMCID: PMC10495607 DOI: 10.1016/j.jdsr.2023.08.007] [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: 11/09/2022] [Revised: 08/02/2023] [Accepted: 08/22/2023] [Indexed: 09/15/2023] Open
Abstract
Zirconia restorations are increasingly popular in dental treatment. Yttria-stabilized zirconia (YSZ) needs to be sintered for clinical applications and novel speed-sintering protocols are being developed for chairside treatments. Whether the properties of speed-sintered YSZ meet clinical requirements, however, remains unclear. Therefore, we conducted a systematic review and meta-analysis on the influence of speed-sintering on the optical and mechanical properties of dental YSZ according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. A literature search was conducted using PubMed, Embase, and Web of Science databases for relevant articles published between January 1, 2010 and February 28, 2022 in English, Chinese, or Japanese. After full-text evaluation and quality assessment, 26 articles were selected. Meta-analysis revealed that speed-sintering does not significantly affect the CIEDE2000-based translucency parameter, contrast ratio, three-point flexural strength, biaxial flexural strength, or fracture toughness of YSZ (p < 0.01) compared to conventional sintering. However, the CIELab-based translucency parameter of conventionally sintered YSZ is higher than that of speed-sintered YSZ. The descriptive analysis indicated that speed-sintering does not affect the hardness of YSZ compared to that of conventionally sintered YSZ. The results indicate that speed-sintering is suitable for preparing YSZ for dental restorations.
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Affiliation(s)
- Hengyi Liu
- Department of Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan
| | - Masanao Inokoshi
- Department of Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan
| | - Kaiqi Xu
- Department of Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan
| | - Watcharapong Tonprasong
- Department of Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan
| | - Shunsuke Minakuchi
- Department of Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan
| | - Bart Van Meerbeek
- KU Leuven (University of Leuven), Department of Oral Health Sciences, BIOMAT & UZ Leuven (University Hospitals Leuven), Dentistry, Kapucijnenvoer 7 blok a, B-3000 Leuven, Belgium
| | - Jef Vleugels
- KU Leuven (University of Leuven), Department of Materials Engineering, Kasteelpark Arenberg 44, BE-3001 Leuven, Belgium
| | - Fei Zhang
- KU Leuven (University of Leuven), Department of Oral Health Sciences, BIOMAT & UZ Leuven (University Hospitals Leuven), Dentistry, Kapucijnenvoer 7 blok a, B-3000 Leuven, Belgium
- KU Leuven (University of Leuven), Department of Materials Engineering, Kasteelpark Arenberg 44, BE-3001 Leuven, Belgium
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12
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Antón X, Liebermann A, Hampe R, Joda T, Stawarczyk B. Impact of high-speed sintering and choice of preshaded monochrome or multilayered blanks on fatigue behavior of 4 mol% yttria-stabilized tetragonal zirconia polycrystal. J Prosthet Dent 2023; 130:639-645. [PMID: 34930599 DOI: 10.1016/j.prosdent.2021.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 10/31/2021] [Accepted: 11/01/2021] [Indexed: 11/25/2022]
Abstract
STATEMENT OF PROBLEM High-speed sintering allows the rapid fabrication of esthetic restorations with adequate flexural strength. However, data on the fatigue behavior of high-speed sintered 4 mol% yttria-stabilized tetragonal zirconia polycrystal (4Y-TZP) are lacking. PURPOSE The purpose of this in vitro study was to examine the effect of high-speed sintering and the preshading of blanks (monochrome versus multilayer) on the fatigue behavior of 4Y-TZP ceramics. MATERIAL AND METHODS Four-point flexural strength specimens (N=405) were fabricated from high-speed sintered multilayer 4Y-TZP (Zolid DRS) processed at 1580 °C for about 20 minutes and conventionally sintered at 1450 °C for about 10 hours, multilayer 4Y-TZP (Zolid Gen-x), and monochrome 4Y-TZP (Ceramill Zolid HT+PS), the control group. The specimens were loaded under 5 different dynamic test conditions for fatigue testing (P1-P5). Three were step-stress protocols (P1: 50 N for 5000 cycles; P2: 10 N for 1000 cycles, P3: 5% for 5000 cycles), 1 was tested with a constant force of 720 N (P4), and 1 was tested for different constant load levels (P5). For analysis of P1-P3, the Kaplan-Meier test and Mantel Cox test were performed (α=.05). P4 was analyzed with the Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests, and P5 by creating a load-cycle diagram. A fracture analysis was performed. RESULTS ZMLC showed better fatigue behavior than ZMLH (P≤.006) and ZMOC (P≤.002) in all 3 step-stress protocols (P1-P3). ZMLH showed results comparable with those for ZMOC (P≥.285). In P4 and P5, all materials showed comparable values (P=.163 for P4). CONCLUSIONS The multilayer technique showed a positive effect on the fatigue behavior of 4Y-TZP. In contrast, high-speed sintering negatively influenced the fatigue behavior of multilayer 4Y-TZP. The high-speed sintered material showed no deterioration compared with the conventional sintered monochrome material.
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Affiliation(s)
- Xenia Antón
- Doctoral student, Dental Materials Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany.
| | - Anja Liebermann
- Assistant Professor, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
| | - Rüdiger Hampe
- Guest Researcher, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
| | - Tim Joda
- Professor, Department of Reconstructive Dentistry, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
| | - Bogna Stawarczyk
- Scientific Head, Dental Materials Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
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Liebermann A, Schultheis A, Faber F, Rammelsberg P, Rues S, Schwindling FS. Impact of post printing cleaning methods on geometry, transmission, roughness parameters, and flexural strength of 3D-printed zirconia. Dent Mater 2023; 39:625-633. [PMID: 37179237 DOI: 10.1016/j.dental.2023.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 04/12/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
OBJECTIVE To analyze the impact of different post printing cleaning methods on geometry, transmission, roughness parameters, and flexural strength of additively manufactured zirconia. METHODS Disc-shaped specimens (N = 100) were 3D-printed from 3 mol%-yttria-stabilized zirconia (material: LithaCon 3Y 210; printer: CeraFab 7500, Lithoz) and were cleaned with five different methods (n = 20): (A) 25 s of airbrushing with the dedicated cleaning solution (LithaSol 30®, Lithoz) and 1-week storage in a drying oven (40 °C); (B) 25 s airbrushing (LithaSol 30®) without drying oven; (C) 30 s ultrasonic bath (US) filled with Lithasol30®; (D) 300 s US filled with LithaSol 30®; (E) 30 s US filled with LithaSol 30® followed by 40 s of airbrushing (LithaSol 30®). After cleaning, the samples were sintered. Geometry, transmission, roughness (Ra, Rz), characteristic strengths (σ0), and Weibull moduli (m) were analyzed. Statistical analyses were performed using Kolmogorov-Smirnov-, t-, Kruskal-Wallis-, and Mann-Whitney-U-tests (α < 0.05). RESULTS Short US (C) resulted in the thickest and widest samples. Highest transmission was found for US combined with airbrushing (E, p ≤ 0.004), followed by D and B (same range, p = 0.070). Roughness was lowest for US combined with airbrushing (E, p ≤ 0.039), followed by A and B (same range, p = 0.172). A (σ0 = 1030 MPa, m = 8.2), B (σ0 = 1165 MPa, m = 9.8), and E (σ0 = 1146 MPa, m = 8.3) were significantly stronger (p < 0.001) and substantially more reliable than C (σ0 = 480 MPa, m = 1.9) and D (σ0 = 486 MPa, m = 2.1). SIGNIFICANCE For 3D-printed zirconia, cleaning strategy selection is important. Airbrushing (B) and short US combined with airbrushing (E) were most favorable regarding transmission, roughness, and strength. Ultrasonic cleaning alone was ineffective (short duration) or detrimental (long duration). Strategy E could be particularly promising for hollow or porous structures.
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Affiliation(s)
- A Liebermann
- Department of Prosthetic Dentistry, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - A Schultheis
- Department of Prosthetic Dentistry, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - F Faber
- Department of Prosthetic Dentistry, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - P Rammelsberg
- Department of Prosthetic Dentistry, Heidelberg University Hospital, Heidelberg, Germany
| | - S Rues
- Department of Prosthetic Dentistry, Heidelberg University Hospital, Heidelberg, Germany
| | - F S Schwindling
- Department of Prosthetic Dentistry, Heidelberg University Hospital, Heidelberg, Germany; Department of Prosthetic Dentistry, Medical University Innsbruck, Innsbruck, Austria
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14
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Oyar P, Durkan R. The effects of heating rate and sintering time on the biaxial flexural strength of monolithic zirconia ceramics. BIOMED ENG-BIOMED TE 2023:bmt-2022-0338. [PMID: 36930871 DOI: 10.1515/bmt-2022-0338] [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: 08/26/2022] [Accepted: 03/02/2023] [Indexed: 03/19/2023]
Abstract
The strength of zirconia ceramic materials used in restorations is dependent upon sintering. Varying sintering protocols may affect the biaxial flexural strength of zirconia materials. This in vitro study was conducted to investigate the effects of sintering parameters on the biaxial flexural strength of monolithic zirconia. Two different monoblock zirconia ceramics were used. Following coloration, samples of both types of ceramics were divided into groups according to whether or not biaxial flexural strength testing was performed directly after sintering or following thermocycling. Biaxial flexural strength data was analysed with a Shapiro Wilk normality test, followed by 1-way ANOVA, Tukey post hoc tests for inter-group comparisons, and paired samples t-tests for intra-group comparisons. A significant difference was found between the biaxial flexural strengths of Zircon X and Upcera ceramics before thermocycling (p<0.05). In both Zircon X and Upcera ceramic groups, the thermocycling process created a significant difference in the biaxial flexural strength values of the ceramic samples in Group 6 (p<0.05) which had the slowest heating rate and longest holding time. The zirconia ceramics have higher BFS at higher heating rates either before or after thermocycling. The holding time has significant effects on thermocycling and flexural strength. The zirconia achieved its optimum strength when it sintered at longer time regardless of heating rates.
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Affiliation(s)
- Perihan Oyar
- Professor, Dental Prosthetics Technology, Vocational School of Health Services, Hacettepe University, Ankara, Türkiye
| | - Rukiye Durkan
- Department of Prosthodontics, Faculty of Dentistry, Istanbul Okan University, Istanbul, Türkiye
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15
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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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Conventional, Speed Sintering and High-Speed Sintering of Zirconia: A Systematic Review of the Current Status of Applications in Dentistry with a Focus on Precision, Mechanical and Optical Parameters. J Clin Med 2022; 11:jcm11164892. [PMID: 36013131 PMCID: PMC9409711 DOI: 10.3390/jcm11164892] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/04/2022] [Accepted: 08/17/2022] [Indexed: 01/17/2023] Open
Abstract
The aim of this systematic review was to provide an overview of the technical and clinical outcomes of conventional, speed sintering and high-speed sintering protocols of zirconia in the dental field. Data on precision, mechanical and optical parameters were evaluated and related to the clinical performance of zirconia ceramic. The PICOS search strategy was applied using MEDLINE to search for in vitro and in vivo studies using MeSH Terms by two reviewers. Of 66 potentially relevant studies, 5 full text articles were selected and 10 were further retrieved through a manual search. All 15 studies included in the systematic review were in vitro studies. Mechanical, precision and optical properties (marginal and internal fit, fracture strength and modulus, wear, translucency and opalescence, aging resistance/hydrothermal aging) were evaluated regarding 3-, 4- and 5-YTZP zirconia material and conventional, high- and high-speed sintering protocols. Mechanical and precision results were similar or better when speed or high-speed sintering methods were used for 3-, 4- and 5-YTZP zirconia. Translucency is usually reduced when 3 Y-TZP is used with speed sintering methods. All types of zirconia using the sintering procedures performed mechanically better compared to lithium disilicate glass ceramics but glass ceramics showed better results regarding translucency.
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Mayinger F, Buser R, Laier M, Schönhoff LM, Kelch M, Hampe R, Stawarczyk B. Impact of the material and sintering protocol, layer thickness, and thermomechanical aging on the two-body wear and fracture load of 4Y-TZP crowns. Clin Oral Investig 2022; 26:6617-6628. [PMID: 35840737 DOI: 10.1007/s00784-022-04616-5] [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: 03/03/2022] [Accepted: 07/04/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVES The aim of this study is to investigate the influence of the material and corresponding sintering protocol, layer thickness, and aging on the two-body wear (2BW) and fracture load (FL) of 4Y-TZP crowns. MATERIALS AND METHODS Multi-layer 4Y-TZP crowns in three thicknesses (0.5 mm/1.0 mm/1.5 mm) were sintered by high-speed (Zolid RS) or conventional (Zolid Gen-X) sintering. 2BW of ceramic and enamel antagonist after aging (1,200,000 mechanical-, 6000 thermal-cycles) was determined by 3D-scanning before and after aging and subsequent matching to determine volume and height loss (6 subgroups, n = 16/subgroup). FL was examined initially and after aging (12 subgroups, n = 16/subgroup). Fractographic analyses were performed using light-microscope imaging. Global univariate analysis of variance, one-way ANOVA, linear regression, Spearman's correlation, Kolgomorov-Smirnov, Mann-Whitney U, and t test were computed (alpha = 0.05). Weibull moduli were determined. Fracture types were analyzed using Ciba Geigy table. RESULTS Material/sintering protocol did not influence 2BW (crowns: p = 0.908, antagonists: p = 0.059). High-speed sintered Zolid RS presented similar (p = 0.325-0.633) or reduced (p < 0.001-0.047) FL as Zolid Gen-X. Both 4Y-TZPs showed an increased FL with an increasing thickness (0.5(797.3-1429 N) < 1.0(2087-2634 N) < 1.5(2683-3715 N)mm; p < 0.001). For most groups, aging negatively impacted FL (p < 0.001-0.002). Five 0.5 mm specimens fractured, four showed cracks during and after aging. CONCLUSIONS High-speed sintered crowns with a minimum thickness of 1.0 mm showed sufficient mechanical properties to withstand masticatory forces, even after a simulated aging period of 5 years. CLINICAL RELEVANCE Despite the manufacturer indicating a thickness of 0.5 mm to be suitable for single crowns, a minimum thickness of 1.0 mm should be used to ensure long-term satisfactory results.
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Affiliation(s)
- Felicitas Mayinger
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany.
| | - Ramona Buser
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany.,Department of Reconstructive Dentistry and Gerodontology, University of Bern, Freiburgstrasse 7, 3007, Bern, Switzerland
| | - Maximilian Laier
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Lisa Marie Schönhoff
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Matthias Kelch
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Rüdiger Hampe
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
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Kim YK, Yoon HI, Kim DJ, Han JS. Comparative analysis on intaglio surface trueness, wear volume loss of antagonist, and fracture resistance of full-contour monolithic zirconia crown for single-visit dentistry under simulated mastication. J Adv Prosthodont 2022; 14:173-181. [PMID: 35855321 PMCID: PMC9259349 DOI: 10.4047/jap.2022.14.3.173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE This analysis aimed to evaluate the intaglio surface trueness, antagonist’s wear volume loss, and fracture resistance of full-contour crowns of (Y, Nb)-stabilized fully-sintered zirconia (FSZ), 4 mol% or 5 mol% yttria-stabilized partially sintered zirconia (4YZ or 5YZ) with high-speed sintering. MATERIALS AND METHODS A total of 42 zirconia crowns were separated into three groups: FSZ, 4YZ, and 5YZ (n = 14). The intaglio surface trueness of the crowns was evaluated at the inner surface, occlusal, margin, and axial areas and reported as root-mean-square, positive and negative average deviation. Half of the specimens were aged for 120,000 cycles in the chewing simulator, and the wear volume loss of antagonist was measured. Before and after chewing, the fracture load was measured for each group. The trueness values were analyzed with Welch's ANOVA, and the wear volume loss with the Kruskal-Wallis tests. Effect of the zirconia type and aging on fracture resistance of crowns was tested using two-way ANOVA. RESULTS The intaglio surface trueness measured at four different areas of the crown was less than 50 µm, regardless of the type of zirconia. No significant P in wear volume loss of antagonists were detected among the groups (P > .05). Both the type of zirconia and aging showed statistically significant effects on fracture resistance (P < .05). CONCLUSION The full-contour crowns of FSZ as well as 4YZ or 5YZ with high-speed sintering were clinically acceptable, in terms of intaglio surface trueness, antagonist’s wear volume loss, and fracture resistance after simulated mastication.
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Affiliation(s)
- Yong-Kyu Kim
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Hyung-In Yoon
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Dae-Joon Kim
- Department of Dentistry, VASIC Research Center, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Jung-Suk Han
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
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Comparison of Testing Designs for Flexural Strength of 3Y-TZP and 5Y-PSZ Considering Different Surface Treatment. MATERIALS 2022; 15:ma15113915. [PMID: 35683212 PMCID: PMC9181921 DOI: 10.3390/ma15113915] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 12/04/2022]
Abstract
The aim of this study was to analyze the influence of different surface treatments and the corresponding surface roughness on the ball-on-three-balls test and piston-on-three-balls test for measuring flexural strength 3Y-TZP and 5Y-PSZ. Additionally, the influence of cutting the material into the specimens when pre-sintered or fully sintered was analyzed. A total of 120 specimens for each material group, 3Y-TZP zirconia (Katana HT, Kuraray) and the 4 different layers of multilayered 5Y-PSZ zirconia (Katana UTML, Kuraray), were produced. The used material was cut into half of the specimens in a fully sintered stage, the other half was cut when pre-sintered. Each subgroup was divided into 3 different surface treatment groups being air abraded with 50 µm alumina particles at 1 bar pressure, ground with 600 SiC paper or polished up to 1 µm with a polycristalline diamond suspension. These were then analyzed by X-ray diffraction (XRD) (N = 3) and tested for flexural strength using the ball-on-three-balls test (N = 10) or piston-on-three-balls test (N = 10). For 3Y-TZP groups different surface roughness did not result in statistically significant differences in flexural strength but cutting the specimens in fully sintered state significantly reduced flexural strength of 1133 ± 109 to 741 ± 81 MPa. For 5Y-PSZ groups air abrasion of the specimens with alumina particles significantly reduced the flexural strength of 562 ± 68 MPa to 358 ± 58 MPa. Cutting and surface treatment in pre-sintered or fully sintered state had no significant influence. Flexural strength testing with the ball-on-three-balls test resulted in about 20% higher strengths compared to the piston-on-three-balls test. Results of both tests showed the same tendencies when compared.
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Kim YK, Han JS, Yoon HI. Evaluation of intaglio surface trueness, wear, and fracture resistance of zirconia crown under simulated mastication: a comparative analysis between subtractive and additive manufacturing. J Adv Prosthodont 2022; 14:122-132. [PMID: 35601347 PMCID: PMC9095451 DOI: 10.4047/jap.2022.14.2.122] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 11/08/2022] Open
Abstract
PURPOSE This in-vitro analysis aimed to compare the intaglio trueness, the antagonist's wear volume loss, and fracture load of various single-unit zirconia prostheses fabricated by different manufacturing techniques. MATERIALS AND METHODS Zirconia crowns were prepared into four different groups (n = 14 per group) according to the manufacturing techniques and generations of the materials. The intaglio surface trueness (root-mean-square estimates, RMS) of the crown was measured at the marginal, axial, occlusal, and inner surface areas. Half of the specimens were artificially aged in the chewing simulator with 120,000 cycles, and the antagonist's volume loss after aging was calculated. The fracture load for each crown group was measured before and after hydrothermal aging. The intaglio trueness was evaluated with Welch's ANOVA and the antagonist's volume loss was assessed by the Kruskal-Wallis tests. The effects of manufacturing and aging on the fracture resistance of the tested zirconia crowns were determined by two-way ANOVA. RESULTS The trueness analysis of the crown intaglio surfaces showed surface deviation (RMS) within 50 µm, regardless of the manufacturing methods (P = .053). After simulated mastication, no significant differences in the volume loss of the antagonists were observed among the zirconia groups (P = .946). The manufacturing methods and simulated chewing had statistically significant effects on the fracture resistance (P < .001). CONCLUSION The intaglio surface trueness, fracture resistance, and antagonist's wear volume of the additively manufactured 3Y-TZP crown were clinically acceptable, as compared with those of the 4Y- or 5Y-PSZ crowns produced by subtractive milling.
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Affiliation(s)
- Yong-Kyu Kim
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Jung-Suk Han
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Hyung-In Yoon
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
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21
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New generation CAD-CAM materials for implant-supported definitive frameworks fabricated by using subtractive technologies. BIOMED RESEARCH INTERNATIONAL 2022; 2022:3074182. [PMID: 35281596 PMCID: PMC8906986 DOI: 10.1155/2022/3074182] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/05/2022] [Accepted: 02/02/2022] [Indexed: 12/31/2022]
Abstract
Innovations in digital manufacturing enabled the fabrication of implant-supported fixed dental prostheses (ISFDPs) in a wide variety of recently introduced materials. Computer-aided design and computer-aided manufacturing (CAD-CAM) milling allows the fabrication of ISFDPs with high accuracy by reducing the fabrication steps of large-span frameworks. The longevity of ISFDPs depends on the overall mechanical properties of the framework material including its fit, and the physical properties of the veneering material and its bond with the framework. This comprehensive review summarizes the recent information on millable CAD-CAM framework materials such as pre-sintered soft alloys, fiber-reinforced composite resins, PEEK, and PEKK in high-performance polymer family, and 4Y-TZP. Even though promising results have been obtained with the use of new generation millable CAD-CAM materials for ISFDPs, clinical studies are lacking and future research should focus on the overall performance of these millable materials in both static and dynamic conditions.
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22
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Cho MH, Seol HJ. Effect of Cooling Rate during Glazing on the Mechanical and Optical Properties of Monolithic Zirconia with 3 mol% Yttria Content. MATERIALS (BASEL, SWITZERLAND) 2021; 14:7474. [PMID: 34885629 PMCID: PMC8658760 DOI: 10.3390/ma14237474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 11/17/2022]
Abstract
Glazing is the final heat treatment process in the manufacturing of a monolithic zirconia prosthesis. Herein, the effect of cooling rate during zirconia glazing was investigated. A 3 mol% yttria-stabilized tetragonal zirconia polycrystal was glazed at the general cooling rate suggested by the manufacturer, as well as at higher and lower cooling rates, and the differences in flexural strength, hardness, optical properties, and crystal structure were evaluated. A higher cooling rate did not affect the flexural strength, hardness, grain size, optical properties, or crystal structure; however, the Weibull modulus decreased by 1.3. A lower cooling rate did not affect the flexural strength, optical properties, or crystal structure; however, the Weibull characteristic strength increased by 26.7 MPa and the Weibull modulus increased by 0.9. The decrease in hardness and the increase in grain size were statistically significant; however, the numerical differences were negligible. This study revealed that a lower cooling rate provides more reliable flexural strength. Therefore, glazing can proceed at a general cooling rate, which takes 3-4 min; however, glazing at a lower cooling rate will provide a more consistent flexural strength if desired, despite being time-consuming.
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Affiliation(s)
- Mi-Hyang Cho
- Department of Dental Lab, Wonkwang Health Science University, Iksan-si 54538, Jeonbuk-do, Korea;
| | - Hyo-Joung Seol
- Department of Dental Materials, Dental and Life Science Institute, School of Dentistry, Pusan National University, Yangsan-si 50612, Gyeongsangnam-do, Korea
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Liu JF, Yang CC, Luo JL, Liu YC, Yan M, Ding SJ. Bond strength of self-adhesive resin cements to a high transparency zirconia crown and dentin. J Dent Sci 2021; 17:973-983. [PMID: 35756805 PMCID: PMC9201647 DOI: 10.1016/j.jds.2021.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/06/2021] [Indexed: 11/25/2022] Open
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Mourouzis P, Tolidis K. Effects of milling method and artificial ageing on optical properties of high translucent zirconia for chairside restorations. Dent Mater 2021; 38:108-120. [PMID: 34823879 DOI: 10.1016/j.dental.2021.10.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 10/19/2021] [Accepted: 10/29/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVES This study aimed to evaluate the optical properties of highly translucent 5 mol% yttria, partially stabilised monolithic zirconia, and 3 mol% yttria-stabilised tetragonal zirconia after their subjection to different milling methods and artificial ageing. METHODS Two types of pre-shaded zirconia materials were used: inCoris TZI C and Katana STML. A total of 120 specimens were categorised according to the milling method (dry or wet-milling) and the solution used for milling (fresh distilled water or impregnated water with residues of CAD/CAM ceramic materials). The translucency and contrast ratios of all specimens were calculated after they were subjected to sintering and accelerated ageing. The material phase composition was tested before and after ageing, using X-ray diffraction analysis to evaluate T-M phase transformation. Data were statistically analysed via a three-way analysis of variance between the subject factors, the material and milling method, and the within-subject factor, ageing. The analysis of covariance model was used to analyse the changes in translucency and contrast ratio between baseline and ageing, with statistical significance set at p < 0.05. RESULTS Katana STML and inCoris TZI C showed the highest translucency when dry-milled (21.9 ± 1.4, and 11.8 ± 0.7, respectively), and the lowest when milled with used impregnated water (5.4 ± 1.2 and 10.7 ± 1.3, respectively). Wet-milling using impregnated water, should be avoided owing to the saturation of alumina particles. Accelerated ageing resulted in the same pattern for both materials. Significance Dry milling of highly translucent zirconia can result in higher translucency and lower contrast ratio values.
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Affiliation(s)
- Petros Mourouzis
- Department of Dental Tissues Pathology and Therapeutics, Division of Operative Dentistry, Faculty of Dentistry, Aristotle University of Thessaloniki, Greece.
| | - Kosmas Tolidis
- Department of Dental Tissues Pathology and Therapeutics, Division of Operative Dentistry, Faculty of Dentistry, Aristotle University of Thessaloniki, Greece
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Oyar P, Durkan R, Deste G. Effects of sintering time and hydrothermal aging on the mechanical properties of monolithic zirconia ceramic systems. J Prosthet Dent 2020; 126:688-691. [PMID: 33039187 DOI: 10.1016/j.prosdent.2020.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 10/23/2022]
Abstract
STATEMENT OF PROBLEM The flexural strength of zirconia restorations is partially dependent on the sintering process. Changes in sintering protocols as well as hydrothermal aging may affect the flexural strength of zirconia materials. PURPOSE The purpose of this in vitro study was to investigate how changes in sintering parameters and hydrothermal aging affect the biaxial flexural strength of monolithic zirconia. MATERIAL AND METHODS Specimens were produced from 2 translucent monolithic zirconia ceramics (Zircon X ST, Upcera YZ HT). After coloring, specimens of both ceramics were distributed into groups and subjected to 1 of 6 different sintering protocols. Half were subjected to biaxial flexural strength tests directly after sintering, and the remaining specimens were subjected to hydrothermal aging and then to biaxial flexural strength testing. Biaxial flexural strength data were analyzed by using a statistical software program. Normality of distribution was determined by the Shapiro-Wilk test. Biaxial flexural strength data were compared among groups by using 1-way ANOVA and Tukey post hoc tests, and intragroup data were compared by using paired specimens t tests (α=.05). RESULTS The highest overall biaxial flexural strength value was obtained in UW-II. The highest biaxial flexural strength for Zircon X was obtained in ZX-VI and ZX-HTA-VI, whereas the highest biaxial flexural strength for Upcera was obtained in UW-II before hydrothermal aging and in UW-HTA-V after aging (P<.05). CONCLUSIONS The biaxial flexural strength of Zircon X increased with longer sintering times. Upcera specimens were more fracture-resistant than Zircon X both before and after hydrothermal aging. Based on these findings, longer sintering times are recommended to increase the strength of monolithic zirconia.
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Affiliation(s)
- Perihan Oyar
- Associate Professor, Department of Dental Prosthetics Technology, Vocational School of Health Services, Hacettepe University, Ankara, Turkey.
| | - Rukiye Durkan
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Afyon Kocatepe University, Afyonkarahisar, Turkey
| | - Gonca Deste
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Bursa Uludağ University, Bursa, Turkey
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