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Song HS, Huh YH, Park CJ, Cho LR, Ko KH. Evaluation of shear bond strength based on substructure materials and ceramic veneering techniques. J Prosthodont 2024. [PMID: 38822528 DOI: 10.1111/jopr.13889] [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: 01/14/2024] [Accepted: 05/15/2024] [Indexed: 06/03/2024] Open
Abstract
PURPOSE Bilayered restorations have both the strength of the substructure material and the esthetics of the veneer material; however, they should have appropriate bonding between the two materials. This study aimed to evaluate the shear bond strength (SBS) according to the substructure material and veneering technique used in bilayered restorations. MATERIALS AND METHODS The experimental group was divided into four groups (n = 15 per group) based on the substructure materials (cobalt-chromium [Co-Cr] alloy and 3 mol% yttrium-stabilized tetragonal zirconia polycrystal [3Y-TZP]) and veneering techniques (pressing and layering). Veneering was performed with disk shape (diameter: 5 mm, height: 2 mm) on a substructure using each veneering technique. Shear stress was applied to the interface of the substructure and the veneering ceramic using a universal testing machine. The shear bond strength, according to the substructure and veneering technique, was analyzed using a two-way analysis of variance with a post-hoc Tukey's honestly significant difference test. The failure mode was observed, and the surface was analyzed using a scanning electron microscope and energy-dispersive spectroscopy. RESULTS The shSBS of the Co-Cr alloy and 3Y-TZP substructure was not different (p > 0.05); however, the pressing technique showed a higher SBS than the layering technique (p < 0.05). The SBS did not differ depending on the veneering technique in the Co-Cr alloys (p > 0.05), whereas the SBS in the pressing technique was higher than that in the layering technique for 3Y-TZP (p < 0.05). In the layering technique, the Co-Cr alloy showed a higher SBS than 3Y-TZP (p < 0.05). In the failure mode, mixed failure occurred most frequently in all groups. Extensive elemental interdiffusion was observed through the opaque layer in the Co-Cr alloy, regardless of the veneering technique. In 3Y-TZP, a wider range of elemental interdiffusion was observed in the pressing technique than in the layering technique. CONCLUSIONS In bilayered restorations with a 3Y-TZP substructure, the pressing technique yielded higher bonding strength than layering. Using the layering technique, 3Y-TZP showed a lower SBS than the Co-Cr alloy. In bilayered restorations using 3Y-TZP as a substructure, the veneering technique and thermal compatibility of the materials must be considered.
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Affiliation(s)
- Han-Sol Song
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Yoon-Hyuk Huh
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Chan-Jin Park
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Lee-Ra Cho
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Kyung-Ho Ko
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
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Mangoush E, Garoushi S, Vallittu P, Lassila L. Load-bearing capacity and wear characteristics of short fiber-reinforced composite and glass ceramic fixed partial dentures. Eur J Oral Sci 2023; 131:e12951. [PMID: 37641165 DOI: 10.1111/eos.12951] [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: 08/04/2023] [Accepted: 08/15/2023] [Indexed: 08/31/2023]
Abstract
The aim of this study was to evaluate load-bearing capacity and wear performance of experimental short fiber-reinforced composite (SFRC) and conventional lithium-disilicate CAD/CAM fabricated fixed partial dentures (FPDs). Two groups (n = 12/group) of three-unit CAD/CAM fabricated posterior FPDs were made. The first group used experimental SFRC blocks, and the second group fabricated from lithium-disilicate (IPS e.max CAD). All FPDs were luted on a zirconia testing jig with dual-curing resin cement. Half of FPDs per group were quasi-statically loaded until fracture. The other half experienced cyclic fatigue aging (100.000 cycles, Fmax = 500 N) before loading quasi-statically until fracture. Fracture mode was examined using SEM. Wear test was performed using 15,000 loading cycles. Both material type and aging had a significant effect on the load-bearing capacity of FPDs. Experimental SFRC CAD without fatigue aging had significantly the highest load-bearing capacity (2096 ± 149N). Cyclic fatigue aging decreased the load-bearing capacity of the SFRC group (1709 ± 188N) but increased it for the lithium-disilicate group (1546 ± 155N). Wear depth values of SFRC CAD (29.3μm) were significantly lower compared to lithium-disilicate (54.2μm). Experimental SFRC CAD demonstrated the highest load-bearing capacity before and after cyclic fatigue aging, and superior wear behavior compared to the control material.
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Affiliation(s)
- Enas Mangoush
- Department of Biomaterials Science and Turku Clinical Biomaterial Center -TCBC, Institute of Dentistry, University of Turku, Turku, Finland
| | - Sufyan Garoushi
- Department of Biomaterials Science and Turku Clinical Biomaterial Center -TCBC, Institute of Dentistry, University of Turku, Turku, Finland
| | - Pekka Vallittu
- Department of Biomaterials Science and Turku Clinical Biomaterial Center -TCBC, Institute of Dentistry, University of Turku, Turku, Finland
- Wellbeing Services County of South-West Finland, Turku, Finland
| | - Lippo Lassila
- Department of Biomaterials Science and Turku Clinical Biomaterial Center -TCBC, Institute of Dentistry, University of Turku, Turku, Finland
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Chokr H, Alshaarani F, Husein HA. Evaluation of the Marginal Fit of Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) Zirconia Bridges Fabricated With Different Firing Cycles of Veneering Porcelain: An In Vitro Study. Cureus 2023; 15:e34842. [PMID: 36923172 PMCID: PMC10010574 DOI: 10.7759/cureus.34842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2023] [Indexed: 02/12/2023] Open
Abstract
Introduction Zirconia provides adequate mechanical strength to be used as a framework for all ceramic prostheses. Such prostheses must be covered with suitable porcelain to obtain good aesthetic results. The aim To study the effect of the firing cycle numbers of veneering ceramics (one cycle, two cycles, and three cycles) on the marginal fit of computer-aided design (CAD) and computer-aided manufacturing (CAM) zirconia bridges. Materials and methods The sample consisted of 30 full ceramic zirconia bridges, designed by CAD/CAM on a metal bridge model that was designed for this purpose. The sample was divided into three groups (N = 10); group A underwent a single firing cycle, group B underwent two cycles, and group C underwent three cycles. The copper model of the bridge was prepared to be a three-unit bridge, and the impressions of the metal models were taken to make zirconia cores. After that, the veneering ceramic layer and the micro-marginal gap were measured (in microns) on both the buccal and lingual surfaces of each bridge in the sample using the replica technique. A one-way ANOVA test was used to detect statistically significant differences between the groups. Results There were no significant differences between the studied groups in binary comparison; however, the arithmetic mean values of the marginal gap in group C were greater than all the studied groups. Conclusion Within the limitations of the current work, we found that increasing the number of firing cycles of zirconia cores affects the marginal fit; thus, it is recommended to follow the two firing cycle protocol for better adaptation of the CAD/CAM zirconia bridges.
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Affiliation(s)
- Hawraa Chokr
- Department of Fixed Prosthodontics, Faculty of Dental Medicine, Damascus University, Damascus, SYR
| | - Fendi Alshaarani
- Department of Fixed Prosthodontics, Faculty of Dental Medicine, Damascus University, Damascus, SYR
| | - Hassan A Husein
- Department of Fixed Prosthodontics, Faculty of Dental Medicine, Damascus University, Damascus, SYR
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Dawood A, Mohammed A, Saeed M. The effect of adding nanoparticles to dental porcelain on the fracture resistance and bond strength to zirconia core. Indian J Dent Res 2022; 33:193-197. [DOI: 10.4103/ijdr.ijdr_222_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Rodrigues CDS, Aurélio IL, Fraga S, Kaizer MDR, Zhang Y, May LG. Extended glaze firings for porcelain-veneered zirconia: Effects on the mechanical and optical behavior. Dent Mater 2021; 37:1096-1106. [PMID: 33865620 DOI: 10.1016/j.dental.2021.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 03/28/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study evaluated the effect of dwell time (conventional or extended) and cooling protocol (fast or slow) of self-glaze firings on the mechanical (flexural strength and crack propagation) and optical (color and translucency) properties of a porcelain-veneered zirconia system. METHODS Bilayer disc-shaped samples were prepared (Vita VM9 + In-Ceram YZ) and divided according to the final thermal treatment: glaze firing followed by slow cooling (furnace opening at 200 °C) (G-S) or fast cooling (furnace opening at 600 °C) (G-F, manufacturer-recommended protocol), extended glaze firing (15 min of dwell time) followed by slow cooling (EG-S) or fast cooling (EG-F), or no thermal treatment (CTRL). Porcelain roughness (Ra and Rz) was measured before and after glaze firings. Color (ΔE00) and translucency (TP00) alteration were also evaluated. Flexural strength was measured with the piston-on-three-ball test and crack propagation analysis was performed after Vickers indentations. Complementary analyzes of crystalline phase and scanning electron microscopy were carried out. RESULTS Significant effect of dwell time was observed, with extended glaze leading to higher flexural strength and shorter crack lengths. Cracks of EG groups were observed to end in clusters of crystals. Color and translucency changed below perceptibility thresholds. All treatments led to a smoother surface and EG groups reached the lowest Rz values. An extra SiO2 peak was revealed in control and EG groups. No effect of cooling protocol was found. SIGNIFICANCE Extended glaze firing was able to improve the resistance to crack initiation and propagation of porcelain-veneered zirconia without clinically perceptible changes in optical properties.
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Affiliation(s)
- Camila da Silva Rodrigues
- Graduate Program in Dental Sciences, Federal University of Santa Maria, 1000 Roraima Av., T Street, Building 26F, 97105-900 Santa Maria, RS, Brazil
| | - Iana Lamadrid Aurélio
- Graduate Program in Dental Sciences, Federal University of Santa Maria, 1000 Roraima Av., T Street, Building 26F, 97105-900 Santa Maria, RS, Brazil
| | - Sara Fraga
- Department of Conservative Dentistry, Federal University of Rio Grande do Sul, 2492 Ramiro Barcelos Street, 90035-003, Porto Alegre, RS, Brazil
| | - Marina da Rosa Kaizer
- Graduate Program in Dentistry, Positivo University, 5300 Prof. Pedro Viriato Parigot de Souza Street, 81280-330, Curitiba, PR, Brazil
| | - Yu Zhang
- Department of Preventive and Restorative Sciences, University of Pennsylvania, 240 S. 40th Street, Levy 109, Philadelphia, PA 19104, USA
| | - Liliana Gressler May
- Department of Restorative Dentistry, Federal University of Santa Maria, 1000 Roraima Av., T Street, Building 26F, 97105-900 Santa Maria, RS, Brazil.
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Vohra F, Shuwaish MB, Deeb MA, Alhamdan R, Alotaibi N, Abduljabbar T. Comparison of failure loads and compressive stress in Press on metal and Press on Y-TZP copings. Pak J Med Sci 2020; 36:1645-1650. [PMID: 33235590 PMCID: PMC7674887 DOI: 10.12669/pjms.36.7.2472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Objective: The aim of the study was to assess the failure loads and compressive stresses among bilayered press on Y-TZP (POZ) and press on metal (POM) crowns with different core-veneer thickness. Methods: Thirty metal and Y-TZP copings were fabricated using CAD-CAM technology with specified thickness. All copings were veneered with ceramic materials using hot pressing technique, with 2mm and 2.5mm thickness. The different coping veneer thickness of crowns resulted in six study groups, including, POM: Coping/ veneer thickness of 0.7/2mm (Gp1), 0.7/2.5mm (Gp 2) and 1mm/2mm (Gp 3)-POZ: 0.7/2mm (Gp A), 0.7/2.5mm (Gp B) and 1mm/2mm (Gp C). Crowns were cemented to a standard implant analog and failure loads (FL) and compressive stress (CS) was ascertained by controlled load application in a universal testing machine. Data was analysed using ANOVA and multiple comparisons test. Results: The maximum FL were observed in the POM specimens with a C/V ratio of 1/2 (Group 3-1880.67± 256.78 N), however the lowest FL were exhibited by POZ crowns with 1/2 C/V ratio (Group C-611.89± 72.79 N). Mean FL and CS were significantly higher in POM compared to POZ crowns in respective groups. Increasing the coping-veneer thickness increased FL and CS among POM crowns. Increasing veneer and decreasing coping thickness improved FL and CS among POZ crowns. Conclusions: Press on metal specimen showed higher resistance to fracture than Press on Y-TZP specimens. Improved failure loads were observed in thin coping and thick veneers among Press on Y-TZP crowns.
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Affiliation(s)
- Fahim Vohra
- Fahim Vohra, Department of Prosthetic Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Mohammed Bin Shuwaish
- Mohammed Bin Shuwaish, Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Modhi Al Deeb
- Modhi Al Deeb, Department of Prosthetic Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Rana Alhamdan
- Rana Al Hamdan, Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Naif Alotaibi
- Naif Alotaibi, Department of General Dentistry, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Tariq Abduljabbar
- Tariq Abduljabbar, Department of Prosthetic Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
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Meirelles PD, da Rocha LS, Pecho OE, Della Bona A, Benetti P. Intraoral repair of a chipped porcelain-zirconia restoration. J ESTHET RESTOR DENT 2020; 32:444-450. [PMID: 32442351 DOI: 10.1111/jerd.12592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 04/09/2020] [Accepted: 04/20/2020] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Ceramic fracture is an undesirable outcome of the rehabilitation with fixed partial dentures (FPD), mainly because it may involve additional cost and clinical time for intraoral repair or replacement of the restoration. This clinical report describes a 5 years survival intraoral repair of a chipped porcelain veneered zirconia framework restoration using a resin-based composite. CLINICAL CONSIDERATIONS A FPD of porcelain veneered zirconia was made. After 18 months, the FPD presented a porcelain chip (porcelain fracture without exposure to the zirconia structure) on the buccal side of the pontic. An epoxy resin replica of the fractured surface was obtained and was examined under scanning electron microscopy. Fracture origin was found at the cervical area of the pontic. Intraoral repair by bonding the chipped fragment back in place was performed. After 15 days, the porcelain fragment debonded without patient knowledge and the fragment was lost. Then, intraoral repair using composite resin to restore the fractured area was performed and is still in function to date. CONCLUSIONS Based on the 5-years survival of the performed intraoral repair, the composite resin reconstruction technique has shown to be an adequate alternative treatment for fractured FPD. CLINICAL SIGNIFICANCE A resin composite repair of the fracture site can be performed in one clinical session, using much less time and cost than for the replacement of FPD. This clinical case survived 5 years to date.
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Affiliation(s)
- Potira Dalques Meirelles
- Post-Graduate Program in Dentistry, School of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
| | - Larissa Simião da Rocha
- Post-Graduate Program in Dentistry, School of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
| | - Oscar E Pecho
- Post-Graduate Program in Dentistry, School of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
| | - Alvaro Della Bona
- Post-Graduate Program in Dentistry, School of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
| | - Paula Benetti
- Post-Graduate Program in Dentistry, School of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
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Alessandretti R, Borba M, Della Bona A. Cyclic contact fatigue resistance of ceramics for monolithic and multilayer dental restorations. Dent Mater 2020; 36:535-541. [DOI: 10.1016/j.dental.2020.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 11/29/2022]
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A simple 3-point flexural method for measuring fracture toughness of the dental porcelain to zirconia bond and other brittle bimaterial interfaces. J Prosthodont Res 2020; 64:391-396. [PMID: 32063538 DOI: 10.1016/j.jpor.2019.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/25/2019] [Accepted: 11/05/2019] [Indexed: 11/22/2022]
Abstract
PURPOSE Porcelain fused to zirconia prostheses are widely used, but porcelain chipping, fracture, spalling and delamination are common clinical problems. Conventional bond strength testing is inherently unsuited for studying interfacial failure by cracking in brittle materials. Instead, fracture toughness is a more meaningful parameter because it can assess the robustness of the interface when subjected to loading, but fracture mechanics approaches have only rarely been used. Our purpose was to develop a novel, simple, 3-point flexural methodology and mathematical analysis to measure the fracture toughness of the porcelain to zirconia interface. METHODS Equations were derived to estimate the fracture toughness of the bond by computing the interfacial energy release rate for a novel simple 3-point flexural test model. The test was validated using two different configurations of layered zirconia/porcelain beams (n = 10), approximating the dimensions of a fixed dental prosthesis, fabricated from a tetragonal polycrystalline zirconium dioxide partially stabilized with yttria and a feldspathic dental porcelain. RESULTS Cracking along the bimaterial interface was produced and measured as a discrete event. Fracture toughness means (standard deviations) computed from the measured energy release rate, for the porcelain to zirconia interface in two different specimen configurations were 7.9 (1.3) and 5.3 (1.6) J/m2. CONCLUSIONS Equations were derived to measure interfacial fracture toughness of brittle materials using a novel simple 3-point flexural test method. The test was then validated; estimates for the fracture toughness for the porcelain to zirconia bond, overlapped with previously published data derived from more complex 4-point notched tests.
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Bakitian F, Papia E, Larsson C, Vult von Steyern P. Evaluation of Stress Distribution in Tooth-Supported Fixed Dental Prostheses Made of Translucent Zirconia with Variations in Framework Designs: A Three-Dimensional Finite Element Analysis. J Prosthodont 2020; 29:315-322. [PMID: 31971307 DOI: 10.1111/jopr.13146] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2020] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To evaluate the influence of the framework designs on the stress distribution within tooth-supported partially veneered fixed dental prostheses (FDPs) made of translucent zirconia under simulated loads using a three-dimensional finite element analysis (3D-FEA). MATERIAL AND METHODS For a linear 3D-FEA, simplified 3D solid models of prepared abutment teeth (first premolar and first molar) with different 3-unit FDPs were created. The models with different FDP designs-monolithic zirconia (control); semi-monolithic zirconia with 0.3 mm veneer thickness (SM0.3); semi-monolithic zirconia with 0.5 mm veneer thickness (SM0.5); semi-monolithic zirconia with 0.5 mm veneer thickness supported with cap design (SMC), and semi-monolithic zirconia with 0.5 mm veneer thickness supported with wave design (SMW)-were analyzed using 3D-FEA. The elastic properties of the components (bone, dentine, cement, translucent zirconia, and veneering porcelain) were obtained from the published data for FEA. Simulated static loading forces (300 N) were applied at 10° oblique direction over six points in the occlusal surfaces of the FDPs. Maximum principal stress, shear stress, and safety factor were calculated and analyzed among the different models. RESULTS Semi-monolithic with cap design showed the smallest maximum principal stress levels in the veneering porcelain compared to all other models (SM0.3, SM0.5, SMW). The SM0.3 had lower maximum principal stress levels in the veneering porcelain compared to SM0.5. Regarding stresses in the zirconia framework, all models had comparable results in maximum principal tensile stresses, except SMW had a lower value. Maximum principal stress levels were located in the veneer component of SM0.3, SM0.5, and SMW, whereas, such levels were observed in the cervical areas of the zirconia frameworks of SMC and control. The SM0.3 had the highest maximum shear stress levels at the zirconia-veneer interface, while SMW had the lowest shear values. The 3D-FEA models with different FDP designs showed different minimum safety factor levels. CONCLUSIONS Framework and veneer designs play a significant role in the stress distribution of the partially veneered zirconia FDPs under loading. The FDPs with zirconia frameworks with cap design minimize the maximum principal tensile stress in the veneering porcelain. The FDPs with 0.3-mm-veneering porcelain show low maximum principal tensile stress in the veneering porcelain, but highest maximum shear stress at the zirconia-veneer interface. The FDPs with wave design of zirconia frameworks minimize the maximum shear stress considerably.
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Affiliation(s)
- Fahad Bakitian
- Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden.,Department of Restorative Dentistry, Faculty of Dentistry, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Evaggelia Papia
- Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Christel Larsson
- Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Per Vult von Steyern
- Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden
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Esquivel-Upshaw JF, Mecholsky JJ, Clark AE, Jenkins R, Hsu SM, Neal D, Ren F. Factors influencing the survival of implant-supported ceramic-ceramic prostheses: A randomized, controlled clinical trial. J Dent 2020; 103S:100017. [PMID: 34059304 PMCID: PMC9993352 DOI: 10.1016/j.jjodo.2020.100017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 02/29/2020] [Accepted: 04/08/2020] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE The goals of this research are: (1) to determine the clinical survival of ceramic-ceramic 3-unit implant supported fixed dental prostheses (FDPs) compared with control metal-ceramic and; (2) to analyze the effects of design parameters such as connector height, radius of curvature of gingival embrasure, and occlusal veneer thickness. MATERIALS AND METHODS This randomized, controlled clinical trial enrolled 96 participants with 129 3-unit implant-supported FDPs. Participants were randomized to receive different design combinations to include FDP material, thickness of occlusal veneer ceramic, radius of curvature of gingival embrasure and connector height. Participants were recalled for 6 months, 1year and yearly thereafter for the next 5 years. FDPs were examined for evidence of fracture and radiographs were made to assess viability of implants. Fractographic analyses and Kaplan Meier survival analysis was used to analyze the data. RESULTS 27 FDPs, representing 21%, exhibited chipping fractures of the veneer during the 5-year observation period. There was no statistically significant effect of type of material, veneer thickness, radius of curvature of gingival embrasure and connector height on occurrence of fracture. Fractographic and occlusal analyses reveal that fractures originated from the occlusal surface and that occlusion was the most important factor in determining survival. Stresses calculated at failure demonstrated lower values compared with in vitro data. CONCLUSION Implant-supported ceramic-ceramic prosthesis is a viable alternative to metal-ceramic. Survival analysis for both materials were comparable and design parameters employed in this study did not affect survival as long as zirconia was used as the core material.
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Affiliation(s)
- J F Esquivel-Upshaw
- Division of Prosthodontics, Restorative Dental Sciences, University of Florida College of Dentistry, Gainesville, FL, United States.
| | - J J Mecholsky
- Department of Materials Science and Engineering, University of Florida Herbert Wertheim College of Engineering, Gainesville, FL, United States
| | - A E Clark
- Division of Prosthodontics, Restorative Dental Sciences, University of Florida College of Dentistry, Gainesville, FL, United States
| | - R Jenkins
- Dental Clinical Research Unit, University of Florida College of Dentistry Office of Research, Gainesville, FL, United States
| | - S M Hsu
- Division of Prosthodontics, Restorative Dental Sciences, University of Florida College of Dentistry, Gainesville, FL, United States
| | - D Neal
- Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, United States
| | - F Ren
- Department of Chemical Engineering, University of Florida Herbert Wertheim College of Engineering, Gainesville, FL, United States
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Ansarifard E, Mohaghegh M, Firouzmandi M, Ramazani L. Marginal fit of full contour monolithic zirconia in different thicknesses and layered zirconia crowns. J Int Soc Prev Community Dent 2020; 10:652-658. [PMID: 33282776 PMCID: PMC7685281 DOI: 10.4103/jispcd.jispcd_25_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/12/2020] [Accepted: 08/14/2020] [Indexed: 11/05/2022] Open
Abstract
Aim: Use of monolithic zirconia for fabrication of all-ceramic crowns eliminates several shortcomings of layered zirconia crowns. Long-term success of restorations highly depends on the marginal fit. The crown thickness is among the factors that affect the marginal integrity. Meanwhile, reduced thickness of crowns has several advantages such as preservation of tooth structure. The aim of this study was to evaluate the marginal fit of monolithic zirconia crowns in reduced thickness and to compare the marginal fit of full-contour monolithic zirconia in different thicknesses with layered zirconia crowns. Materials and Methods: In this in vitro study, two standard brass dies (7 mm × 5 mm length diameter) were prepared with a heavy chamfer finish line with 0.5 and 1 mm depth. By using a CAD-CAM system, 30 crowns were made in three groups (n = 10) of 1-mm thick layered zirconia, 1-mm thick monolithic zirconia, and 0.5-mm thick monolithic zirconia. Crowns were placed on master dies and randomly numbered. The marginal gap was measured on 18 points by using a digital microscope (×230). The mean ± standard deviation (SD) values were calculated and analyzed by Statistical Package for the Social Sciences (SPSS) software program through Kruskal–Wallis and Mann–Whitney tests (α = 0.05). Results: The marginal gap of 1-mm layered zirconia was significantly different from that of 1-mm monolithic zirconia (P = 0.001) and 0.5-mm monolithic zirconia (P = 0.004). Analysis of variance (ANOVA) revealed no significant difference between 0.5 and 1 mm thicknesses of monolithic zirconia (P = 0.141). Conclusion: Marginal gap in all the three groups was clinically acceptable. The two different thicknesses of monolithic zirconia crowns had no significant effect on the restoration marginal fit; however, layered zirconia crowns showed a significantly higher marginal gap than monolithic zirconia crowns.
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Investigations into the interface failure of yttria partially stabilised zirconia - porcelain dental prostheses through microscale residual stress and phase quantification. Dent Mater 2019; 35:1576-1593. [PMID: 31522759 DOI: 10.1016/j.dental.2019.08.098] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 08/15/2019] [Indexed: 11/22/2022]
Abstract
OBJECTIVES Yttria Partially Stabilised Zirconia (YPSZ) is a high strength ceramic which has become widely used in porcelain veneered dental copings due to its exceptional toughness. Within these components the residual stress and crystallographic phase of YPSZ close to the interface are highly influential in the primary failure mode; near interface porcelain chipping. In order to improve present understanding of this behaviour, characterisation of these parameters is needed at an improved spatial resolution. METHODS In this study transmission micro-focus X-ray Diffraction, Raman spectroscopy, and focused ion beam milling residual stress analysis techniques have, for the first time, been used to quantify and cross-validate the microscale spatial variation of phase and residual stress of YPSZ in a prosthesis cross-section. RESULTS The results of all techniques were found to be comparable and complementary. Monoclinic YPSZ was observed within the first 10μm of the YPSZ-porcelain interface with a maximum volume fraction of 60%. Tensile stresses were observed within the first 150 μm of the interface with a maximum value of ≈300 MPa at 50 μm from the interface. The remainder of the coping was in mild compression at ≈-30MPa, with shear stresses of a similar magnitude also being induced by the YPSZ phase transformation. SIGNIFICANCE The analysis indicates that the interaction between phase transformation, residual stress and porcelain creep at YPSZ-porcelain interface results in a localised porcelain fracture toughness reduction. This explains the increased propensity of failure at this location, and can be used as a basis for improving prosthesis design.
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Juntavee N, Serirojanakul P. Influence of different veneering techniques and thermal tempering on flexural strength of ceramic veneered yttria partially stabilized tetragonal zirconia polycrystalline restoration. J Clin Exp Dent 2019; 11:e421-e431. [PMID: 31275514 PMCID: PMC6599706 DOI: 10.4317/jced.55722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 04/01/2019] [Indexed: 11/05/2022] Open
Abstract
Background Different technique for ceramic veneering and thermal tempering process are expected to be a reason for alteration in strength of ceramic veneered zirconia. This study evaluates the effect of different veneering technique and varied thermal tempering process on flexural strength of ceramic veneered zirconia. Material and Methods Ceramic veneered zirconia bars (25 mm length, 4 mm width, 0.7&1.0mm of zirconia & ceramic thickness) were prepared from zirconia block (e.max® ZirCAD), sintered at 1500°C for 4 hours, and veneered with ceramics with different techniques including CAD-fused using e.max CAD® (C), Pressed-on using e.max® Zirpress (P), and layering using e.max® ceram (L), with different tempering process through fast (F), medium (M), and slow (L) cooling (n=15). The specimens were determined for flexural strength on a universal testing machine. ANOVA and Bonferroni's multiple comparisons were used to determine for significant difference (α=0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σc). The interfaces were microscopically examined. The phase transformation of zirconia was determined using X ray diffraction. Results The mean±sd (MPa), m, σc of flexural strength were 922.06±83.45, 12.78, 958.32 for CF, 924.26±74.64, 14.28, 959.62 for CM, 930.25±92.42, 11.83, 970.83 for CS, 518.29±59.97, 10.11, 542.97 for PF, 516.50±67.51, 8.75, 539.17 for PM, and 520.51±42.38, 14.59, 544.51 for PS, 604.36±64.09, 11.28, 630.67 for LF, 583.81±56.95, 11.67, 609.81 for LM, 547.33±52.23, 12.19, 569.36 for LS. The flexural strength was significantly affected by veneering technique (p<0.05). No significant effect on flexural strength upon tempering process was evidenced (P >0.05). Phase transformation from t→m related with veneering and tempering procedure. Conclusions Strength of ceramic veneered zirconia associated with different veneering techniques, but not directly related with tempering process. CAD-on ceramic veneering zirconia is benefit for enhancing the strength of ceramic bilayer and was recommended as a method for ceramic veneering zirconia. Key words:CAD-CAM, cooling process, flexural strength, thermal tempering, zirconia.
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Affiliation(s)
- Niwut Juntavee
- Department of Prosthodontics, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Pitsinee Serirojanakul
- Division of Biomaterials and Prosthodontics Research, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
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Longhini D, Rocha C, de Oliveira LT, Olenscki NG, Bonfante EA, Adabo GL. Mechanical Behavior of Ceramic Monolithic Systems With Different Thicknesses. Oper Dent 2019; 44:E244-E253. [PMID: 31265354 DOI: 10.2341/18-083-l] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES This study assessed the fully stabilized zirconia (FSZ) Prettau Anterior, the partially stabilized zirconia (PSZ) Prettau, and the lithium disilicate IPS e.max CAD (LD) through microstructural and mechanical characterization and effect of thickness on fracture load of the ceramics. METHODS AND MATERIALS Disk-shaped specimens (12 mm diameter and 1.2 mm thickness) were prepared for biaxial flexural strength (BFS) and Weibull statistics (n=30). For the fracture load static test (FLST) and Weibull statistics (n=30), disk-shaped specimens 12 mm in diameter and thicknesses of 0.5 mm, 1 mm, and 1.5 mm were cemented on an epoxy-resin substrate. RESULTS BFS (MPa) results were PSZ: 683.0 ± 70.23; FSZ: 438.6 ± 64.1; and LD: 248.6 ± 37.3. One-way analysis of variance (ANOVA) for BFS was significant (p<0.001), and the Tukey post hoc test showed differences among all ceramics. There was difference in characteristic strength, but there was no difference in Weibull modulus. Two-way ANOVA for FLST was significant for ceramic (p<0001), thickness (p<0001), and interaction (p<0001). There was no difference among all ceramics at the 0.5 mm thickness. PSZ had higher values for the 1.0 mm and 1.5 mm thicknesses. LD of 1.5 mm thickness exhibited a higher FLST than FSZ. CONCLUSIONS PSZ had the highest BFS, but when cemented on a substrate, all ceramics with 0.5 mm thickness behaved similarly. Despite the lower BFS, LD had a fracture load similar or superior to FSZ when cemented on a substrate.
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Alayad AS. Ceramic Fracture in Bilayered All-ceramic Indirect Restoration: A Review of the Literature. JOURNAL OF ADVANCED ORAL RESEARCH 2019. [DOI: 10.1177/2320206819831560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: High incidence of fracture of all-ceramic crowns may compromise the clinical outcome and is a source of hassle for both patients and dentist. Objective: The objective of the present review was to identify reasons for high ceramic fracture or chipping and to minimize these incidents in dental settings. Methods: The final search strategy was executed on Medline via OvidSP, PubMed, and Web of Knowledge. Studies meeting the following inclusion criteria were included in the current review. (1) Literature in English language only, (2) in vitro studies, (3) studies providing evidence on ceramic fracture, and (4) studies only related to indirect restoration and ceramics. Moreover, the exclusion criteria were based on (1) articles other than English, (2) studies reporting direct restoration, (3) any non–peer-reviewed gray literature, and (4) studies discussing fracture other than ceramic material. Results: From the initial search strategy, 101 studies were retrieved from different databases. A total of 3 studies were scrutinized through other resources. Following duplicate removal (n = 24), 80 studies were screened for the title and abstract. Moreover (n = 49) studies were shortlisted for full text and review. Following review and discussion in the final result, only 26 studies were included. Conclusions: Many improvements in the material, its fabrication process, and surface treatments can reduce the incidence of fracture within the material.
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Affiliation(s)
- Abdullah Saeed Alayad
- Department of Restorative Dental Science, King Saud University College of Dentistry, Riyadh, Saudi Arabia
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17
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Taufer C, Della Bona A. Edge chipping resistance of ceramics bonded to a dentine analogue. J Mech Behav Biomed Mater 2019; 90:587-590. [DOI: 10.1016/j.jmbbm.2018.11.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/07/2018] [Accepted: 11/10/2018] [Indexed: 10/27/2022]
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18
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A thick frame decreases the fracture toughness of veneering ceramics used for zirconia-based all-ceramic restorations. J Prosthodont Res 2018; 63:184-192. [PMID: 30579782 DOI: 10.1016/j.jpor.2018.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 11/08/2018] [Accepted: 11/09/2018] [Indexed: 11/22/2022]
Abstract
PURPOSE To investigate the influence of firing condition and thickness of a yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) frame on the fracture toughness of veneering ceramics. METHODS Layering and pressable ceramics without frames or on 0.8- and 1.2-mm-thick Y-TZP frames were fired with 5 schedules (normal and 4 customized conditions). The fracture toughness of the ceramics was measured at 0.5-2.5mm from the frame by the indentation fracture method. Crystal structures at the measurement points were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). RESULTS Under customized firing conditions, the fracture toughness of the layering ceramic significantly decreased, particularly near the frame. Use of a 1.2-mm-thick frame significantly decreased the fracture toughness of both layering and pressable ceramics compared to ceramics without the frame. The decreased fracture toughness only occurred close (0.5 and 1.0mm) to the frame. XRD analysis showed identical diffraction patterns between points near and far from the frame, suggesting that the decreased fracture toughness was not due to crystal defects or impurities. SEM revealed many microcracks and large crystals in layering ceramic near the 1.2-mm-thick frame, possibly resulting from the thermal properties of the zirconia frame, such as large heat capacity and low thermal conductivity. CONCLUSIONS Modification of the firing conditions from the manufacturer's instructions and inclusion of a thick Y-TZP frame decreased the fracture toughness of veneering ceramics at the interface, suggesting that a thick frame would pose a potent fracture risk in veneering ceramics used for zirconia-based all-ceramic restorations.
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Sawada T, Wagner V, Schille C, Spintzyk S, Schweizer E, Geis-Gerstorfer J. Effect of slow-cooling protocol on biaxial flexural strengths of bilayered porcelain-ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) disks. Dent Mater 2018; 35:270-282. [PMID: 30522698 DOI: 10.1016/j.dental.2018.11.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/13/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVE The present study investigated the biaxial flexural strengths of bilayered ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) disks with various layering porcelains veneered using a slow-cooling protocol. METHODS Five porcelain materials (VITA VM9, Cercon Ceram Kiss, and Vintage ZR with experimental coefficient of thermal expansions; CTEs of 8.45, 9.04, and 9.61ppm/°C) were veneered on Ce-TZP/A disks and slow-cooled after firing to fabricate bilayered specimens (core-to-porcelain thickness: 0.8mm/1.5mm). Biaxial flexural strengths of the specimens with the porcelain layer in tension were tested based on the piston-on-three-ball method (ISO 6872:2008). The data were statistically analyzed using Weibull distribution and Fisher's exact test. RESULTS Tensile stresses were observed in the entire porcelain layer while compressive stress at the surface of the Ce-TZP/A layer shifted to tensile stress at the interface between the materials. The cases of small CTE mismatches between the materials showed high Weibull characteristic strengths at the internal and external surfaces of the specimens, except the VM9 group (CTE: 9.0-9.2ppm/°C). The maximum tensile stress was observed on the surface of the porcelain layer, where cracks originated and continuously propagated into the Ce-TZP layer. The Ce-TZP/A fractured into two pieces for large CTE mismatches between the materials, resulting in significantly lower flexural strengths than those fracturing into three pieces for small CTE mismatches. SIGNIFICANCE Flexural strengths and fracture behaviors of bilayered porcelain-Ce-TZP/A disks were influenced by the CTE mismatches, and a small CTE mismatch between the materials was preferred when using a slow-cooling protocol.
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Affiliation(s)
- Tomofumi Sawada
- Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany; Department of Biomedical Engineering, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba-cho, Shiwa-gun, Iwate 028-3694, Japan.
| | - Verena Wagner
- Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany.
| | - Christine Schille
- Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany.
| | - Sebastian Spintzyk
- Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany.
| | - Ernst Schweizer
- Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany.
| | - Jürgen Geis-Gerstorfer
- Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany.
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Reginato VF, Kemmoku DT, Caldas RA, Bacchi A, Pfeifer CS, Consani RLX. Characterization of Residual Stresses in Veneering Ceramics for Prostheses with Zirconia Framework. Braz Dent J 2018; 29:347-353. [PMID: 30462760 DOI: 10.1590/0103-6440201801990] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 04/13/2018] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to evaluate the influence of the coefficient of thermal expansion (CTE or α) and glass transition temperature (Tg) of three veneering ceramics used with zirconia frameworks of full-arch fixed prostheses. The generation of residual stresses and linear contraction after the simulation of the cooling process and mechanical loading were measured. The analysis was based on the finite element method in three-dimensional model of a maxillary full-arch fixed prosthesis with zirconia framework (e.max ZirCAD) and veneer by felsdpathic ceramics (GEC - IPS e.max Ceram, GVM - Vita VM9 and GLC - Lava Ceram). The linear contraction simulation was performed by cooling the structures from the Tg of each veneer ceramic at room temperature (25°C). A loading of 100 N on the occlusal region of the first molar was performed. The magnitude of the maximum principal stress (smax) and linear contraction were evaluated. The levels of CTE mismatch between veneering ceramics and framework showed no relevant influence on smax and linear contraction. The Tg values of the veneer ceramic showed to be directly proportional to amount of smax and linear contraction. The GEC presented the highest values of smax and linear contraction. The GVM and GLC did not present significant differences between them. In conclusion, GVM was similar to GLC, while GEC presented differences in relation to other veneer ceramics in terms of residual stress and linear contraction.
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Affiliation(s)
- Vagner Flávio Reginato
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil
| | | | - Ricardo Armini Caldas
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil
| | - Ataís Bacchi
- Department of Prosthodontics, IMED - Faculdade Meridional, Passo Fundo, RS, Brazil
| | - Carmem Silvia Pfeifer
- Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Healthand Science University, Portland, OR, USA
| | - Rafael Leonardo Xediek Consani
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil
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Sawada T, Schille C, Wagner V, Spintzyk S, Schweizer E, Geis-Gerstorfer J. Biaxial flexural strength of the bilayered disk composed of ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) and veneering porcelain. Dent Mater 2018; 34:1199-1210. [DOI: 10.1016/j.dental.2018.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/17/2018] [Accepted: 05/02/2018] [Indexed: 10/16/2022]
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Alayad AS. Effect of Zirconia Core Thickness and Veneer Firing Cycle on the Biaxial Flexural Strength of Veneering Ceramic. J Prosthodont 2018; 29:26-33. [PMID: 29968266 DOI: 10.1111/jopr.12929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2018] [Indexed: 10/28/2022] Open
Abstract
PURPOSE To evaluate the influence of various Y-TZP thicknesses and veneer firing cycles on the strength of two ceramic veneers. MATERIALS AND METHODS 180 Y-TZP cores of 0.5, 1.0, and 5.0 mm thickness were prepared followed by sintering in a high temperature furnace; 180 presintered veneering ceramic discs (Vita VM9 porcelain and e.max Ceram) were also prepared using a mold. The discs were placed on zirconia plates (zirconia cores) of different thickness (0.5, 1.0, and 5.0 mm) and exposed to different firing cycles (Vita VM9 porcelain-910, 930, and 950°C; e.max Ceram-750, 770, and 790°C). Ball-on-three-balls flexural strength test was performed (universal testing machine) at a crosshead speed of 0.5 mm/min. Scanning electron microscopy of fractured specimens was performed. Means and standard deviations of flexural strength were analyzed using Tukey-Kramer HSD test for multiple comparisons. RESULTS Specimens within material groups showed no significant difference (p > 0.05) for flexural strength with respect to Y-TZP core thickness (0.5, 1.0, and 5.0 mm) (VM9 [117.30 ± 14.328, 117.75 ± 13.66, 113.75 ± 20.10], e.max Ceram [94.79 ± 17.5, 100.02 ± 14.7, 95.23 ± 15.4]). Flexural strength within material groups with respect to different firing cycles ([VM9-910, 930, 950°C], e.max Ceram [750, 770, 790°C]), for VM9 (111.49 ± 15.7, 120.86 ± 13.2, 116.46 ± 18.4), and e.max Ceram (94.64 ± 15.2, 101.6 ± 16.69, 93.8 ± 15.20) showed no significant difference (p > 0.05). CONCLUSIONS Different zirconia thicknesses (0.5, 1.0, and 5.0 mm) and veneer firing cycles for Vita VM9 and e.max ceramics failed to show any significant influence on their biaxial flexural strengths.
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Affiliation(s)
- Abdullah Saeed Alayad
- Assistant Professor, Department of Restorative Dental Sciences, College Of Dentistry, King Saud University, Riyadh, Saudi Arabia
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Candido LM, Miotto LN, Fais LMG, Cesar PF, Pinelli LAP. Mechanical and Surface Properties of Monolithic Zirconia. Oper Dent 2018; 43:E119-E128. [DOI: 10.2341/17-019-l] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Purpose:
This study compared monolithic zirconia with conventional ones based on mean roughness (Ra), Vickers hardness (VHN), topography, transmittance, grain size, flexural strength (FS), Weibull modulus, and fractographic behavior.
Methods and Materials:
One monolithic (Prettau Zircon [PR group]) and two conventional (ICE Zirkon Transluzent [IZ group] and BloomZir [BL group]) zirconias were used. Specimens were tested using a profilometer, a microhardness tester, a scanning electron microscope, a spectrophotometer, and a Universal Testing Machine (EMIC DL 2000). Ra, VHN, grain size, and transmittance were analyzed using the Kruskal-Wallis test associated with Dunn test (α=0.05). FS was analyzed using one-way analysis of variance with the Tukey honestly significant difference test (α=0.05).
Results:
Means and standard deviations of roughness, after sintering (Ra, in μm) and VHN, were, respectively, 0.11 ± 0.01, 1452.16 ± 79.49, for the PR group; 0.12 ± 0.02, 1466.72 ± 91.76, for the IZ group; and 0.21 ± 0.08, 1516.06 ± 104.02, for the BL group. BL was statistically rougher (p<0.01) than PR and IZ. Hardness was statistically similar (p=0.30) for all groups. Means and standard deviations of FS (in MPa) were 846.65 ± 81.97 for the PR group, 808.88 ± 117.99 for the IZ group, and 771.81 ± 114.43 for the BL group, with no statistical difference (p>0.05). Weibull moduli were 12.47 for the PR group, 7.24 for the IZ group, and 6.31 for the BL group, with no statistical differences. The PR and BL groups had higher transmittance values and grain sizes than the IZ group (p<0.05). Although the BL group had some fractures that originated in the center of the tensile surface, fractographic analyses showed the same fracture pattern.
Conclusions:
All tested zirconia showed similar VHN, and the monolithic zirconia had similar roughness compared to one of the conventional zirconias. In addition, the monolithic zirconia showed similar flexural strength and Weibull modulus compared to the others even though its mean grain size was larger. The total transmittance of monolithic zirconia was higher than only one of the conventional zirconias tested.
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Affiliation(s)
- LM Candido
- Lucas Miguel Candido, PhD student, Department of Dental Materials and Prosthodontics, Araraquara Dental School, Universidade Estadual Paulista, Araraquara, Brazil
| | - LN Miotto
- Larissa Natiele Miotto, master degree, Department of Dental Materials and Prosthodontics, Araraquara Dental School, Universidade Estadual Paulista, Araraquara, Brazil
| | - LMG Fais
- Laiza Maria Grassi Fais, postdoctoral research, Department of Dental Materials and Prosthodontics, Araraquara Dental School, Universidade Estadual Paulista, Araraquara, Brazil
| | - PF Cesar
- Paulo Francisco Cesar, associate professor, Department of Biomaterials and Oral Biology, São Paulo Dental School, Universidade de São Paulo, São Paulo, Brazil
| | - LAP Pinelli
- Lígia Antunes Pereira Pinelli, associate professor, Department of Dental Materials and Prosthodontics, Araraquara Dental School, Universidade Estadual Paulista, Araraquara, Brazil
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Ramos V, Øilo M. Thermal cracks of implant-based zirconia four-unit restorations: A fractographic analysis of two restorations fractured during production. J Prosthet Dent 2018; 120:327-330. [PMID: 29627215 DOI: 10.1016/j.prosdent.2017.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 10/17/2022]
Abstract
Two zirconia-based 4-unit restorations intended for the same patient fractured during the veneering process even though the prolonged cooling protocol recommended by the manufacturers was used. Fractographic analyses revealed that both restorations fractured as a result of thermal shock, but at different times during production. Further investigation is necessary to optimize the firing protocols for large zirconia-based restorations and avoid fracture due to thermal shock.
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Affiliation(s)
- Van Ramos
- Associate Professor, Director, Graduate Prosthodontics, University of Washington, Seattle, Wash
| | - Marit Øilo
- Associate Professor, Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Bergen, Norway.
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Ebadian B, Mosharraf R, Abbasi M. Effect of ceramic cooling protocols and zirconia coloring on fracture load of zirconia-based restorations. Dent Res J (Isfahan) 2018; 15:17-24. [PMID: 29497443 PMCID: PMC5806426 DOI: 10.4103/1735-3327.223612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Background: Residual thermal stresses in dental porcelains can cause clinical failure. Porcelain cooling protocols may affect the amount of residual stresses within porcelain and also porcelain–zirconia bond strength. The objective of this study was to assess the effect of cooling protocols on the fracture load of porcelain veneered zirconia restorations. Materials and Methods: Forty zirconia bars (31 mm × 6.5 mm × 1.35 mm ± 0.1 mm) were fabricated by computer-aided design and computer-aided manufacturing technology. Half of the specimens were immersed in the coloring agent for 2 min before sintering (yellow group). Thus, the specimens were divided into two groups of white (W) and yellow (Y) samples (n = 20). Heat-pressed ceramic was applied to all bars. After pressing, half of the samples in each group were immediately removed from the oven (fast cooling) while the other specimens remained in the partially open door (30%) oven until the temperature reached to 500°C. Samples were thermocycled for 5000 cycles and subjected to modified four-point flexural strength test by a universal testing machine at a crosshead speed of 0.5 mm/min. Two-way ANOVA, One-way ANOVA followed by post hoc Tukey honest significant difference tests were used for data analysis (α = 0.05). Results: Fractures were cohesive in all samples (within the porcelain adjacent to the interface). Two-way ANOVA showed that the effect of cooling protocol on the fracture load of samples was statistically significant (P < 0.001). In addition, the fracture load of W and Y groups was significantly different (P < 0.001). The white slow group showed the highest fracture load (179.88 ± 23.43 N). Conclusion: Slow cooling protocol should be preferably applied for zirconia restorations. Coloring agent used in this study had a significant negative effect on fracture load.
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Affiliation(s)
- Behnaz Ebadian
- Department of Prosthodontics, Dental Implant Research Center, School of Dentistry, Isfahan University of Medical Science, Isfahan, Iran
| | - Ramin Mosharraf
- Department of Prosthodontics, Dental Material Research Center, School of Dentistry, Isfahan University of Medical Science, Isfahan, Iran
| | - Mahsa Abbasi
- Department of Prosthodontics, School of Dentistry, Shahrekord University of Medical Science, Shahrekord, Iran
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Bakitian F, Seweryniak P, Papia E, Larsson C, Vult von Steyern P. Fracture strength of veneered translucent zirconium dioxide crowns with different porcelain thicknesses. ACTA BIOMATERIALIA ODONTOLOGICA SCANDINAVICA 2017; 3:74-83. [PMID: 29242815 PMCID: PMC5724800 DOI: 10.1080/23337931.2017.1403288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/26/2017] [Accepted: 11/07/2017] [Indexed: 11/28/2022]
Abstract
Objective: To evaluate fracture strength of veneered translucent zirconium dioxide crowns designed with different porcelain layer thicknesses. Materials and Methods: Sixty crowns, divided into six groups of 10, were used in this study. Groups were divided according to different thicknesses of porcelain veneer on translucent zirconium dioxide cores of equal thickness (0.5 mm). Porcelain thicknesses were 2.5, 2.0, 1.0, 0.8, 0.5 and 0.3 mm. Crowns were artificially aged before loaded to fracture. Determination of fracture mode was performed using light microscope. Results: Group 1.0 mm showed significantly (p ≤ .05) highest fracture loads (mean 1540 N) in comparison with groups 2.5, 2.0 and 0.3 mm (mean 851, 910 and 1202 N). There was no significant difference (p>.05) in fracture loads among groups 1.0, 0.8 and 0.5 mm (mean 1540, 1313 and 1286 N). There were significantly (p ≤ .05) more complete fractures in group 0.3 mm compared to all other groups which presented mainly cohesive fractures. Conclusions: Translucent zirconium dioxide crowns can be veneered with minimal thickness layer of 0.5 mm porcelain without showing significantly reduced fracture strength compared to traditionally veneered (1.0–2.0 mm) crowns. Fracture strength of micro-veneered crowns with a layer of porcelain (0.3 mm) is lower than that of traditionally veneered crowns but still within range of what may be considered clinically sufficient. Porcelain layers of 2.0 mm or thicker should be used where expected loads are low only.
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Affiliation(s)
- Fahad Bakitian
- Department of Materials Science and Technology, Faculty of Odontology, Malmö UniversityMalmöSweden.,Department of Restorative Dentistry, Faculty of Dentistry, Umm Al-Qura UniversityMakkahSaudi Arabia
| | | | - Evaggelia Papia
- Department of Materials Science and Technology, Faculty of Odontology, Malmö UniversityMalmöSweden
| | - Christel Larsson
- Department of Materials Science and Technology, Faculty of Odontology, Malmö UniversityMalmöSweden
| | - Per Vult von Steyern
- Department of Materials Science and Technology, Faculty of Odontology, Malmö UniversityMalmöSweden
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Lee HS, Kwon TY. The Application of a Novel Ceramic Liner Improves Bonding between Zirconia and Veneering Porcelain. MATERIALS 2017; 10:ma10091023. [PMID: 28869512 PMCID: PMC5615678 DOI: 10.3390/ma10091023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/29/2017] [Accepted: 08/31/2017] [Indexed: 11/16/2022]
Abstract
The adhesion of porcelain to zirconia is a key factor in the success of bilayered restorations. In this study, the efficacy of a novel experimental liner (EL) containing zirconia for improved bonding between zirconia and veneering porcelain was tested. Four ELs containing various concentrations (0, 3.0, 6.0, and 9.0 wt %) of zirconia were prepared. Testing determined the most effective EL (EL3 containing 3.0 wt % zirconia) in terms of shear bond strength value (n = 15). Three different bar-shaped zirconia/porcelain bilayer specimens were prepared for a three-point flexural strength (TPFS) test (n = 15): no-liner (NL), commercial liner (CL), and EL3. Specimens were tested for TPFS with the porcelain under tension and the maximum load was measured at the first sign of fracture. The strength data were analyzed using one-way ANOVA and Tukey's test (α = 0.05) as well as Weibull distribution. When compared to NL, the CL application had no effect, while the EL3 application had a significant positive effect (p < 0.001) on the flexural strength. Weibull analysis also revealed the highest shape and scale parameters for group EL3. Within the limitations of this study, the novel ceramic liner containing 3.0 wt % zirconia (EL3) significantly enhanced the zirconia/porcelain interfacial bonding.
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Affiliation(s)
- Hee-Sung Lee
- Department of Dental Science, Graduate School, Kyungpook National University, 2-188-1 Samduk-dong, Jung-gu, Daegu 700-412, Korea.
| | - Tae-Yub Kwon
- Department of Dental Biomaterials, School of Dentistry and Institute for Biomaterials Research & Development, Kyungpook National University, 2-188-1 Samduk-dong, Jung-gu, Daegu 700-412, Korea.
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Zaher AM, Hochstedler J, Rueggeberg FA, Kee EL. Shear bond strength of zirconia-based ceramics veneered with 2 different techniques. J Prosthet Dent 2017; 118:221-227. [DOI: 10.1016/j.prosdent.2016.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 11/22/2016] [Accepted: 11/28/2016] [Indexed: 10/20/2022]
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Tang YL, Kim JH, Shim JS, Kim S. The effect of different cooling rates and coping thicknesses on the failure load of zirconia-ceramic crowns after fatigue loading. J Adv Prosthodont 2017; 9:152-158. [PMID: 28680545 PMCID: PMC5483400 DOI: 10.4047/jap.2017.9.3.152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/16/2016] [Accepted: 11/17/2016] [Indexed: 12/04/2022] Open
Abstract
PURPOSE The purpose of this study was to evaluate the influence of different coping thicknesses and veneer ceramic cooling rates on the failure load of zirconia-ceramic crowns. MATERIALS AND METHODS Zirconia copings of two different thicknesses (0.5 mm or 1.5 mm; n=20 each) were fabricated from scanning 40 identical abutment models using a dental computer-aided design and computer-aided manufacturing system. Zirconia-ceramic crowns were completed by veneering feldspathic ceramics under different cooling rates (conventional or slow, n=20 each), resulting in 4 different groups (CONV05, SLOW05, CONV15, SLOW15; n=10 per group). Each crown was cemented on the abutment. 300,000 cycles of a 50-N load and thermocycling were applied on the crown, and then, a monotonic load was applied on each crown until failure. The mean failure loads were evaluated with two-way analysis of variance (P=.05). RESULTS No cohesive or adhesive failure was observed after fatigue loading with thermocycling. Among the 4 groups, SLOW15 group (slow cooling and 1.5 mm chipping thickness) resulted in a significantly greater mean failure load than the other groups (P<.001). Coping fractures were only observed in SLOW15 group. CONCLUSION The failure load of zirconia-ceramic crowns was significantly influenced by cooling rate as well as coping thickness. Under conventional cooling conditions, the mean failure load was not influenced by the coping thickness; however, under slow cooling conditions, the mean failure load was significantly influenced by the coping thickness.
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Affiliation(s)
- Yu Lung Tang
- Nonsan Yonsei Suite Dental Clinic, Nonsan, Chungnam, Republic of Korea
| | - Jee-Hwan Kim
- Department of Prosthodontics, Yonsei University Dental Hospital, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - June-Sung Shim
- Department of Prosthodontics, Yonsei University Dental Hospital, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - Sunjai Kim
- Department of Prosthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Republic of Korea
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Abstract
AIM To evaluate the resistance to axial forces of screw-retained monolithic high translucency zirconia (mHTZr) crowns compared with high translucency zirconia + feldspathic ceramic (HTZrC) crowns, low translucency zirconia + feldspathic ceramic (LTZrC) crowns, and metal-ceramic (MC) crowns, and also to observe the different fracture patterns between all groups. METHODS Twenty-four crowns were fabricated (6 of each group) and loaded until failure, using a testing machine with a 5.0-kN load cell. RESULTS Mean fracture results varied between 1092.7 N (LTZrC group) and 3439.7 N (mHTZr group). No statistically significant differences were found between the HTZrC, LTZrC, and MC groups. However, statistically significant differences (P < 0.05) were found between mHTZr and the other 3 groups. In the MC group, only chipping of the ceramic veneering occurred. In the mHTZr group, when fracturing occurred, it was of the whole structure. Finally, the LTZrC and HTZrC groups suffered both chipping and core fractures. CONCLUSION High translucency monolithic zirconia implant-supported crowns proved to be the toughest group studied when an axial force was applied. Fracture patterns varied between different materials, chipping being the most common occurrence.
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Miura S, Kasahara S, Yamauchi S, Okuyama Y, Izumida A, Aida J, Egusa H. Clinical evaluation of zirconia-based all-ceramic single crowns: an up to 12-year retrospective cohort study. Clin Oral Investig 2017; 22:697-706. [DOI: 10.1007/s00784-017-2142-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 05/29/2017] [Indexed: 12/21/2022]
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Scherrer SS, Lohbauer U, Della Bona A, Vichi A, Tholey MJ, Kelly JR, van Noort R, Cesar PF. ADM guidance-Ceramics: guidance to the use of fractography in failure analysis of brittle materials. Dent Mater 2017; 33:599-620. [PMID: 28400062 DOI: 10.1016/j.dental.2017.03.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/09/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVES To provide background information and guidance as to how to use fractography accurately, a powerful tool for failure analysis of dental ceramic structures. METHODS An extended palette of qualitative and quantitative fractography is provided, both for in vivo and in vitro fracture surface analyses. As visual support, this guidance document will provide micrographs of typical critical ceramic processing flaws, differentiating between pre- versus post sintering cracks, grinding damage related failures and occlusal contact wear origins and of failures due to surface degradation. RESULTS The documentation emphasizes good labeling of crack features, precise indication of the direction of crack propagation (dcp), identification of the fracture origin, the use of fractographic photomontage of critical flaws or flaw labeling on strength data graphics. A compilation of recommendations for specific applications of fractography in Dentistry is also provided. SIGNIFICANCE This guidance document will contribute to a more accurate use of fractography and help researchers to better identify, describe and understand the causes of failure, for both clinical and laboratory-scale situations. If adequately performed at a large scale, fractography will assist in optimizing the methods of processing and designing of restorative materials and components. Clinical failures may be better understood and consequently reduced by sending out the correct message regarding the fracture origin in clinical trials.
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Affiliation(s)
- Susanne S Scherrer
- Division of Fixed Prosthodontics and Biomaterials, University Clinic of Dental Medicine, University of Geneva, Geneva, Switzerland.
| | - Ulrich Lohbauer
- Research Laboratory for Dental Biomaterials, Dental Clinic 1, University of Erlangen-Nuernberg, Erlangen, Germany.
| | - Alvaro Della Bona
- Post-Graduate Program in Dentistry, Dental School, University of Passo Fundo, Campus I, BR 285, 99052-900, Passo Fundo, RS, Brazil.
| | - Alessandro Vichi
- Department of Medical Biotechnologies, University of Siena, Siena, Italy.
| | - Michael J Tholey
- Research and Development Department VITA Zahnfabrik, Bad Saeckingen, Germany.
| | - J Robert Kelly
- Department of Reconstructive Dentistry and Center for Biomaterials, University of Connecticut Health Center, Farmington, USA.
| | - Richard van Noort
- School of Clinical Dentistry, University of Sheffield, Sheffield, UK.
| | - Paulo Francisco Cesar
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, Brazil.
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33
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Lunt A, Terry A, Ying S, Baimpas N, Sui T, Kabra S, Kelleher J, King S, Khin NT, Korsunsky AM. Characterisation of nanovoiding in dental porcelain using small angle neutron scattering and transmission electron microscopy. Dent Mater 2017; 33:486-497. [PMID: 28279436 DOI: 10.1016/j.dental.2017.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 01/09/2017] [Accepted: 02/16/2017] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Recent studies of the yttria partially stabilised zirconia-porcelain interface have revealed the presence of near-interface porcelain nanovoiding which reduces toughness and leads to component failure. One potential explanation for these nanoscale features is thermal creep which is induced by the combination of the residual stresses at the interface and sintering temperatures applied during manufacture. The present study provides improved understanding of this important phenomenon. METHODS Transmission electron microscopy and small angle neutron scattering were applied to a sample which was crept at 750°C and 100MPa (sample C), a second which was exposed to an identical heat treatment schedule in the absence of applied stress (sample H), and a reference sample in the as-machined state (sample A). RESULTS The complementary insights provided by the two techniques were in good agreement and log-normal void size distributions were found in all samples. The void number density was found to be 1.61μm-2, 25.4μm-2 and 98.6μm-2 in samples A, H and C respectively. The average void diameter in sample A (27.1nm) was found to be more than twice as large as in samples H (10.2nm) and C (11.6nm). The crept data showed the highest skewness parameter (2.35), indicating stress-induced growth of larger voids and void coalescence that has not been previously observed. SIGNIFICANCE The improved insight presented in this study can be integrated into existing models of dental prostheses in order to optimise manufacturing routes and thereby reduce the significant detrimental impact of this nanostructural phenomenon.
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Affiliation(s)
- Alexander Lunt
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK.
| | - Ann Terry
- ISIS Pulsed Neutron and Muon Source, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Siqi Ying
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
| | - Nikolaos Baimpas
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
| | - Tan Sui
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
| | - Saurabh Kabra
- ISIS Pulsed Neutron and Muon Source, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Joe Kelleher
- ISIS Pulsed Neutron and Muon Source, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Stephen King
- ISIS Pulsed Neutron and Muon Source, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Neo Tee Khin
- Specialist Dental Group, Mount Elizabeth Orchard, #08-03/08-08/08-10, 228510, Singapore
| | - Alexander M Korsunsky
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
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Soares LM, Soares C, Miranda ME, Basting RT. Influence of Core-Veneer Thickness Ratio on the Fracture Load and Failure Mode of Zirconia Crowns. J Prosthodont 2017; 28:209-215. [DOI: 10.1111/jopr.12601] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2017] [Indexed: 11/30/2022] Open
Affiliation(s)
- Luciana Mara Soares
- Department of Restorative Dentistry; Herman Ostrow School of Dentistry of USC; Los Angeles CA
| | | | - Milton Edson Miranda
- Department of Prosthodontics; São Leopoldo Mandic Institute and Dental Research Center; Campinas São Paulo Brazil
| | - Roberta Tarkany Basting
- Department of Restorative Dentistry; São Leopoldo Mandic Institute and Dental Research Center; Campinas São Paulo Brazil
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Improving the compatibility of an Y-TZP/porcelain system using a new composite interlayer composition. J Mech Behav Biomed Mater 2017; 65:11-19. [DOI: 10.1016/j.jmbbm.2016.07.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/20/2016] [Accepted: 07/27/2016] [Indexed: 11/23/2022]
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Meirelles PD, Spigolon YO, Borba M, Benetti P. Leucite and cooling rate effect on porcelain-zirconia mechanical behavior. Dent Mater 2016; 32:e382-e388. [PMID: 27707502 DOI: 10.1016/j.dental.2016.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 05/12/2016] [Accepted: 09/03/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE This study investigated the influence of the cooling protocol on the mechanical behavior of Y-TZP veneered with porcelain with different compositions. The tested hypotheses were: (1) Y-TZP infrastructures veneered with porcelain containing leucite in its composition presents higher flexural strength (σ) and reliability (m), and (2) slow cooling protocol results in greater σ and m. METHODS A total of 120 bilayer porcelain-Y-TZP bar-shaped specimens were prepared with the dimensions of 1.8mm (0.8mm Y-TZP±1.0mm porcelain)×4.0mm×16.0mm. Specimens were divided into four groups (n=30) according to the porcelain composition (containing or not leucite) and cooling protocol. Fast cooling was performed by opening the furnace chamber at sintering temperature. For the slow cooling, the chamber was maintained closed until it reached the room temperature. Specimens were tested in three-point bending with the porcelain surface under tension using a universal testing machine, in 37°C water, at 0.5mm/min crosshead speed. Data were analyzed by two-way ANOVA, Tukey post-hoc test (α=0.05) and Weibull. RESULTS Y-TZP veneered with porcelains with different microstructural composition presented similar σ and m values (p=0.718). The cooling protocol had no influence on the σ and m values of the experimental groups (p=0.718). Cracking represented 95% of failures, whereas the initial flaw propagated from the porcelain surface towards the interface. SIGNIFICANCE Y-TZP veneered with porcelain containing or not leucite present similar mechanical behavior and, at 1-mm thickness, is not sensitive to the cooling protocol.
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Affiliation(s)
- P D Meirelles
- University of Passo Fundo, Post-Graduate Program in Dentistry, Passo Fundo, RS, Brazil
| | - Y O Spigolon
- University of Passo Fundo, Post-Graduate Program in Dentistry, Passo Fundo, RS, Brazil
| | - M Borba
- University of Passo Fundo, Post-Graduate Program in Dentistry, Passo Fundo, RS, Brazil
| | - P Benetti
- University of Passo Fundo, Post-Graduate Program in Dentistry, Passo Fundo, RS, Brazil.
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Alghazzawi TF, Janowski GM. Effect of liner and porcelain application on zirconia surface structure and composition. Int J Oral Sci 2016; 8:164-71. [PMID: 27445089 PMCID: PMC5113090 DOI: 10.1038/ijos.2016.20] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2016] [Indexed: 11/13/2022] Open
Abstract
The purpose of this study was to determine if there is an effect of liner and porcelain application (layering and pressing techniques) on the surface of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP), which were exposed to permutations of liner, layered porcelain, and pressed porcelain. Scanning electron microscope (SEM)/energy dispersive spectroscope (EDS) was used to identify changes in composition and microstructure after removing liner and porcelain with hydrofluoric acid. Simulated aging was also conducted to determine the effect of liner and porcelain on low-temperature degradation. The control group had a typical equiaxed grain structure, referred to as unaffected. When covered with liner or porcelain, some areas changed in structure and composition and were termed affected. The frequency of affected structure decreased when liner was covered with either layered porcelain or pressed porcelain. There were statistical differences (P<0.05) in the composition between affected and unaffected for zirconium (layered porcelain with liner: affected=60% (0.8%) (m/m), unaffected=69% (4%), layered porcelain without liner: affected=59% (3%), unaffected=65% (3%)) and oxygen (layered porcelain with liner: affected=35% (2%), unaffected=26% (4%), layered porcelain without liner: affected=35% (3%), unaffected=30% (2%)). However, there were statistical differences (P<0.05) in the composition for zirconium and oxygen of the aged layered porcelain without liner only. The liner should not be used before porcelain application, especially when using the layering technique for zirconia restorations. Furthermore, pressing should be considered the technique of choice over layering.
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Affiliation(s)
- Tariq F Alghazzawi
- Department of Prosthetic Dental Sciences, College of Dentistry, Taibah University, Madina, Kingdom of Saudi Arabia.,Department of Materials Science and Engineering, School of Engineering, The University of Alabama at Birmingham, Birmingham, USA
| | - Gregg M Janowski
- Department of Materials Science and Engineering, School of Engineering, The University of Alabama at Birmingham, Birmingham, USA
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Calha N, Messias A, Guerra F, Martinho B, Neto MA, Nicolau P. Effect of geometry on deformation of anterior implant-supported zirconia frameworks: An in vitro study using digital image correlation. J Prosthodont Res 2016; 61:139-148. [PMID: 27667555 DOI: 10.1016/j.jpor.2016.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 07/20/2016] [Accepted: 08/27/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE To evaluate the effect of geometry on the displacement and the strain distribution of anterior implant-supported zirconia frameworks under static load using the 3D digital image correlation method. METHODS Two groups (n=5) of 4-unit zirconia frameworks were produced by CAD/CAM for the implant-abutment assembly. Group 1 comprised five straight configuration frameworks and group 2 consisted of five curved configuration frameworks. Specimens were cemented and submitted to static load up to 200N. Displacements were captured with two high-speed photographic cameras and analyzed with video correlation system in three spacial axes U, V, W. Statistical analysis was made using the nonparametric Mann-Whitney test. RESULTS Up to 150N loads, the vertical displacements (V axis) were statistically higher for curved frameworks (-267.83±23.76μm), when compared to the straight frameworks (-120.73±36.17μm) (p=0.008), as well as anterior displacements in the W transformed axis (589.55±64.51μm vs 224.29±50.38μm for the curved and straight frameworks), respectively (p=0.008). The mean von Mises strains over the surface frameworks were statistically higher for the curved frameworks under any load. CONCLUSION Within the limitations of this in vitro study, it is possible to conclude that the geometric configuration influences the deformation of 4-unit anterior frameworks under static load. The higher strain distribution and micro-movements of the curved frameworks reflect less rigidity and increased risk of fractures associated to FPDs.
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Affiliation(s)
- Nuno Calha
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal
| | - Ana Messias
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal.
| | - Fernando Guerra
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal
| | - Beatriz Martinho
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal
| | | | - Pedro Nicolau
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal
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Wendler M, Belli R, Petschelt A, Lohbauer U. Spatial distribution of residual stresses in glass-ZrO 2 sphero-cylindrical bilayers. J Mech Behav Biomed Mater 2016; 60:535-546. [DOI: 10.1016/j.jmbbm.2016.03.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 11/28/2022]
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Tanaka CB, Harisha H, Baldassarri M, Wolff MS, Tong H, Meira JB, Zhang Y. Experimental and finite element study of residual thermal stresses in veneered Y-TZP structures. CERAMICS INTERNATIONAL 2016; 42:9214-9221. [PMID: 27087734 PMCID: PMC4831075 DOI: 10.1016/j.ceramint.2016.03.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The main complications of zirconia-based laminated systems are chipping and delamination of veneering porcelain, which has been found to be directly associated with the development of residual thermal stresses in the porcelain layer. This study investigates the effects of cooling rate and specimen geometry on the residual stress states in porcelain-veneered zirconia structures. Bilayers of three different shapes (bars, semi-cylindrical shells, and arch-cubic structures) with 1.5 mm and 0.7 mm thickness of dentin porcelain and zirconia framework, respectively, were subjected to two cooling protocols: slow cooling (SC) at 32 °C/min and extremely-slow cooling (XSC) at 2 °C/min. The residual thermal stresses were determined using the Vickers indentation method and validated by finite element analysis. The residual stress profiles were similar among geometries in the same cooling protocol. XSC groups presented significantly higher tensile stresses (p = 0.000), especially for curved interfaces. XSC is a time-consuming process that showed no beneficial effect regarding residual stresses compared to the manufacturer recommended slow cooling rate.
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Affiliation(s)
- Carina B. Tanaka
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, 433 First Avenue, New York, NY 10010, USA
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Hossam Harisha
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, 433 First Avenue, New York, NY 10010, USA
| | - Marta Baldassarri
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, 433 First Avenue, New York, NY 10010, USA
| | - Mark S. Wolff
- Department of Cariology and Comprehensive Care, Associate Dean for Pre-doctoral Clinical Education, New York University College of Dentistry, 345 East 24th Street, New York, NY 10010, USA
| | - Hui Tong
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, PR China
| | - Josete B.C. Meira
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Yu Zhang
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, 433 First Avenue, New York, NY 10010, USA
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Nawafleh N, Hatamleh MM, Öchsner A, Mack F. The Impact of Core/Veneer Thickness Ratio and Cyclic Loading on Fracture Resistance of Lithium Disilicate Crown. J Prosthodont 2016; 27:75-82. [PMID: 26965298 DOI: 10.1111/jopr.12473] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2015] [Indexed: 11/28/2022] Open
Affiliation(s)
- Noor Nawafleh
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia
| | - Muhanad M Hatamleh
- Cranio-Maxillofacial Prosthetics Unit, King's College Hospital NHS Foundation Trust, London, UK
| | - Andreas Öchsner
- School of Engineering, Griffith University, Queensland, Australia
| | - Florian Mack
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia
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Vichi A, Sedda M, Bonadeo G, Bosco M, Barbiera A, Tsintsadze N, Carrabba M, Ferrari M. Effect of repeated firings on flexural strength of veneered zirconia. Dent Mater 2015; 31:e151-6. [PMID: 26008238 DOI: 10.1016/j.dental.2015.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 01/16/2015] [Accepted: 04/24/2015] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Chipping and/or delamination represent a clinical failure of porcelain fused to zirconia (PFZ) prostheses. Causes and solutions have not been completely clarified. The present study was aimed at evaluating the effects of number of firings on the flexural strength of PFZ specimen. METHODS Forty-five zirconia specimens in shape of bars were cut, sintered and divided in 3 groups (n=15). Group 1: veneering ceramic was layered "in bulk" and fired. Group 2: veneering ceramic was layered in three layers, individually fired. Group 3: veneering ceramic was layered in five layers, individually fired. Each layer thickness was controlled by the use of calibrated molds. The total veneering ceramic thickness for all the specimens was 1.2mm, and the total thickness of the specimen of 2.0mm. Three-point bending test was performed. Fracture load was recorded in Newton and MPa value was calculated taking into account the bi-layered nature of the specimen. Data were statistically analyzed. RESULTS Specimens obtained with on single firing cycle obtained a statistically significant (p<0.001) lower flexural strength (54.61±8.98MPa) than specimens veneered with 3 or 5 firing cycles. The last two obtained very similar results (77.63±13.17MPa and 73.62±12.38MPa respectively) and the differences was not statistically significant. SIGNIFICANCE In bi-layered PFZ specimen, three to five layers and firings determine higher flexural resistance when compared to a single firing. Thus, a 3-layers veneering procedure is recommended to increase flexural resistance. If a 5-layer procedure is necessary to improve esthetics, it does not decrease flexural resistance.
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Affiliation(s)
- A Vichi
- Department of Medical Biotechnologies, University of Siena, Italy.
| | - M Sedda
- Department of Medical Biotechnologies, University of Siena, Italy
| | - G Bonadeo
- Department of Medical Biotechnologies, University of Siena, Italy
| | - M Bosco
- Department of Dentistry, University of Pavia, Italy
| | - A Barbiera
- Department of Medical Biotechnologies, University of Siena, Italy
| | - N Tsintsadze
- Department of Medical Biotechnologies, University of Siena, Italy
| | - M Carrabba
- Department of Medical Biotechnologies, University of Siena, Italy
| | - M Ferrari
- Department of Medical Biotechnologies, University of Siena, Italy
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Ferrari M, Vichi A, Zarone F. Zirconia abutments and restorations: From laboratory to clinical investigations. Dent Mater 2015; 31:e63-76. [DOI: 10.1016/j.dental.2014.11.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 11/19/2014] [Accepted: 11/21/2014] [Indexed: 10/24/2022]
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Slow cooling protocol improves fatigue life of zirconia crowns. Dent Mater 2015; 31:77-87. [DOI: 10.1016/j.dental.2014.10.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 12/22/2013] [Accepted: 10/27/2014] [Indexed: 11/18/2022]
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Nam J, Tokutomi H. Using zirconia-based prosthesis in a complete-mouth reconstruction treatment for worn dentition with the altered vertical dimension of occlusion. J Prosthet Dent 2014; 113:81-5. [PMID: 25438749 DOI: 10.1016/j.prosdent.2014.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 07/15/2014] [Accepted: 08/19/2014] [Indexed: 11/18/2022]
Abstract
This clinical report describes the complete mouth reconstruction of a patient with a worn dentition. Computer-aided design and computer-aided manufacturing processed porcelain fused-to-zirconia prostheses were used to achieve good esthetics, function, and biomechanics.
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Affiliation(s)
- Jung Nam
- Adjunct Assistant Professor, Department of Integrated Reconstructive Dental Sciences, University of the Pacific Arthur A. Dugoni School of Dentistry; Private practice, Saratoga, Calif.
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The impact of luting agents and stiffness of implant-abutments on marginal adaptation, chipping, and fracture resistance of zirconia crowns. J Mech Behav Biomed Mater 2014; 39:279-91. [PMID: 25168974 DOI: 10.1016/j.jmbbm.2014.07.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 07/21/2014] [Indexed: 11/20/2022]
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Kanat-Ertürk B, Çömlekoğlu EM, Dündar-Çömlekoğlu M, Özcan M, Güngör MA. Effect of Veneering Methods on Zirconia Framework-Veneer Ceramic Adhesion and Fracture Resistance of Single Crowns. J Prosthodont 2014; 24:620-8. [DOI: 10.1111/jopr.12236] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- Burcu Kanat-Ertürk
- Department of Prosthodontics; Kocaeli University School of Dentistry; Kocaeli Turkey
| | - Erhan M. Çömlekoğlu
- School of Dentistry, Department of Prosthodontics; Ege University; Izmir Turkey
| | | | - Mutlu Özcan
- Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science; University of Zurich; Zurich Switzerland
| | - Mehmet Ali Güngör
- School of Dentistry, Department of Prosthodontics; Ege University; Izmir Turkey
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Seven-year prospective clinical study on zirconia-based single crowns and fixed dental prostheses. Clin Oral Investig 2014; 19:1137-45. [DOI: 10.1007/s00784-014-1330-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 10/03/2014] [Indexed: 11/26/2022]
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Nishigori A, Yoshida T, Bottino MC, Platt JA. Influence of zirconia surface treatment on veneering porcelain shear bond strength after cyclic loading. J Prosthet Dent 2014; 112:1392-8. [PMID: 25258263 DOI: 10.1016/j.prosdent.2014.05.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 05/19/2014] [Accepted: 05/20/2014] [Indexed: 10/24/2022]
Abstract
STATEMENT OF PROBLEM The influence of yttria-stabilized tetragonal zirconia polycrystal surface treatment on veneering porcelain shear bond strength after cyclic loading is not fully understood. PURPOSE The purpose of this study was to investigate the influence of yttria-stabilized tetragonal zirconia polycrystal surface treatment on veneering porcelain shear bond strength and cyclic loading on the shear bond strength between the 2 materials. MATERIAL AND METHODS A total of 48 cylinder-shaped yttria-stabilized tetragonal zirconia polycrystal specimens were fabricated with computer-aided design and computer-aided manufacturing (CAD/CAM), sintered for 8 hours at 1500°C, ground with 320-grit diamond paper, and divided into 4 groups (n = 12) according to surface treatment as follows: no treatment/control; heat treatment of 650°C to 1000°C at 55°C/min; airborne-particle abrasion with 50-μm alumina at 0.4 MPa pressure for 10 seconds; or heat treatment after abrasion. A veneering porcelain cylinder was built and fired on the prepared yttria-stabilized tetragonal zirconia polycrystal specimens. The shear bond strength was tested with a universal testing machine. Six specimens from each group were subjected to cyclic loading (10000 cycles, 1.5 Hz, 10 N load) before testing. RESULTS The mean ± SD ranged from 10.7 ± 15.4 to 34.1 ± 10.0. Three-way ANOVA found no statistically significant (P > .05) effect of surface treatment and cyclic loading on shear bond strength. The Sidak multiple comparisons procedure found that cyclic loading specimens had significantly lower shear bond strength than noncyclic loading specimens after airborne-particle abrasion without heat treatment (P = .013). CONCLUSIONS Within the limitations of this study, the shear bond strength between yttria-stabilized tetragonal zirconia polycrystal and veneering porcelain was not significantly affected by surface treatment. Airborne-particle abrasion without subsequent heat treatment should be avoided as a surface treatment in fabrication methods.
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Affiliation(s)
- Atsushi Nishigori
- Resident, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, Ind
| | - Takamitsu Yoshida
- Visiting Assistant Professor, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, Ind
| | - Marco C Bottino
- Assistant Professor, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, Ind
| | - Jeffrey A Platt
- Associate Professor, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, Ind.
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