Conventional and modified veneered zirconia vs. metalloceramic: Fatigue and finite element analysis

Nelson R F A Silva; Estevam Bonfante; Brian T Rafferty; Ricardo A Zavanelli; Leandro L Martins; E Dianne Rekow; Van P Thompson; Paulo G Coelho

doi:10.1111/j.1532-849X.2012.00861.x

Conventional and modified veneered zirconia vs. metalloceramic: Fatigue and finite element analysis

Nelson R F A Silva, Estevam Bonfante, Brian T Rafferty, Ricardo A Zavanelli, Leandro L Martins, E Dianne Rekow, Van P Thompson, Paulo G Coelho

Research output: Contribution to journal › Article › peer-review

Abstract

PURPOSE: The purpose of this study was to test the hypothesis that all-ceramic crown core-veneer system reliability is improved by modifying the core design and as a result is comparable in reliability to metal-ceramic retainers (MCR). Finite element analysis (FEA) was performed to verify maximum principal stress distribution in the systems.

MATERIALS AND METHODS: A first lower molar full crown preparation was modeled by reducing the height of proximal walls by 1.5 mm and occlusal surface by 2.0 mm. The CAD-based preparation was replicated and positioned in a dental articulator for specimen fabrication. Conventional (0.5 mm uniform thickness) and modified (2.5 mm height, 1 mm thickness at the lingual extending to proximals) zirconia (Y-TZP) core designs were produced with 1.5 mm veneer porcelain. MCR controls were fabricated following conventional design. All crowns were resin cemented to 30-day aged composite dies, aged 14 days in water and either single-loaded to failure or step-stress fatigue tested. The loads were positioned either on the mesiobuccal or mesiolingual cusp (n = 21 for each ceramic system and cusp). Probability Weibull and use level probability curves were calculated. Crack evolution was followed, and postmortem specimens were analyzed and compared to clinical failures.

RESULTS: Compared to conventional and MCRs, increased levels of stress were observed in the core region for the modified Y-TZP core design. The reliability was higher in the Y-TZP-lingual-modified group at 100,000 cycles and 200 N, but not significantly different from the MCR-mesiolingual group. The MCR-distobuccal group showed the highest reliability. Fracture modes for Y-TZP groups were veneer chipping not exposing the core for the conventional design groups, and exposing the veneer-core interface for the modified group. MCR fractures were mostly chipping combined with metal coping exposure.

CONCLUSIONS: FEA showed higher levels of stress for both Y-TZP core designs and veneer layers compared to MCR. Core design modification resulted in fatigue reliability response of Y-TZP comparable to MCR at 100,000 cycles and 200 N. Fracture modes observed matched with clinical scenarios.

Original language	English (US)
Article number	doi: 10.1111/j.1532-849X.2012.00861.x
Pages (from-to)	433-9
Number of pages	7
Journal	Journal of Prosthodontics
Volume	21
Issue number	6
DOIs	https://doi.org/10.1111/j.1532-849X.2012.00861.x
State	Published - Aug 2012

Keywords

Computer Simulation
Computer-Aided Design
Crowns
Dental Porcelain
Dental Prosthesis Design
Dental Stress Analysis
Dental Veneers
Finite Element Analysis
Humans
Metal Ceramic Alloys
Survival Analysis
Yttrium
Zirconium

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10.1111/j.1532-849X.2012.00861.x

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Silva, N. R. F. A., Bonfante, E., Rafferty, B. T., Zavanelli, R. A., Martins, L. L., Rekow, E. D., Thompson, V. P., & Coelho, P. G. (2012). Conventional and modified veneered zirconia vs. metalloceramic: Fatigue and finite element analysis. Journal of Prosthodontics, 21(6), 433-9. Article doi: 10.1111/j.1532-849X.2012.00861.x. https://doi.org/10.1111/j.1532-849X.2012.00861.x

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title = "Conventional and modified veneered zirconia vs. metalloceramic: Fatigue and finite element analysis",

abstract = "PURPOSE: The purpose of this study was to test the hypothesis that all-ceramic crown core-veneer system reliability is improved by modifying the core design and as a result is comparable in reliability to metal-ceramic retainers (MCR). Finite element analysis (FEA) was performed to verify maximum principal stress distribution in the systems.MATERIALS AND METHODS: A first lower molar full crown preparation was modeled by reducing the height of proximal walls by 1.5 mm and occlusal surface by 2.0 mm. The CAD-based preparation was replicated and positioned in a dental articulator for specimen fabrication. Conventional (0.5 mm uniform thickness) and modified (2.5 mm height, 1 mm thickness at the lingual extending to proximals) zirconia (Y-TZP) core designs were produced with 1.5 mm veneer porcelain. MCR controls were fabricated following conventional design. All crowns were resin cemented to 30-day aged composite dies, aged 14 days in water and either single-loaded to failure or step-stress fatigue tested. The loads were positioned either on the mesiobuccal or mesiolingual cusp (n = 21 for each ceramic system and cusp). Probability Weibull and use level probability curves were calculated. Crack evolution was followed, and postmortem specimens were analyzed and compared to clinical failures.RESULTS: Compared to conventional and MCRs, increased levels of stress were observed in the core region for the modified Y-TZP core design. The reliability was higher in the Y-TZP-lingual-modified group at 100,000 cycles and 200 N, but not significantly different from the MCR-mesiolingual group. The MCR-distobuccal group showed the highest reliability. Fracture modes for Y-TZP groups were veneer chipping not exposing the core for the conventional design groups, and exposing the veneer-core interface for the modified group. MCR fractures were mostly chipping combined with metal coping exposure.CONCLUSIONS: FEA showed higher levels of stress for both Y-TZP core designs and veneer layers compared to MCR. Core design modification resulted in fatigue reliability response of Y-TZP comparable to MCR at 100,000 cycles and 200 N. Fracture modes observed matched with clinical scenarios.",

keywords = "Computer Simulation, Computer-Aided Design, Crowns, Dental Porcelain, Dental Prosthesis Design, Dental Stress Analysis, Dental Veneers, Finite Element Analysis, Humans, Metal Ceramic Alloys, Survival Analysis, Yttrium, Zirconium",

author = "Silva, {Nelson R F A} and Estevam Bonfante and Rafferty, {Brian T} and Zavanelli, {Ricardo A} and Martins, {Leandro L} and Rekow, {E Dianne} and Thompson, {Van P} and Coelho, {Paulo G}",

note = "{\textcopyright} 2012 by the American College of Prosthodontists.",

year = "2012",

month = aug,

doi = "10.1111/j.1532-849X.2012.00861.x",

language = "English (US)",

volume = "21",

pages = "433--9",

journal = "Journal of Prosthodontics",

issn = "1059-941X",

publisher = "Wiley-Blackwell Publishing Ltd",

number = "6",

}

TY - JOUR

T1 - Conventional and modified veneered zirconia vs. metalloceramic

T2 - Fatigue and finite element analysis

AU - Silva, Nelson R F A

AU - Bonfante, Estevam

AU - Rafferty, Brian T

AU - Zavanelli, Ricardo A

AU - Martins, Leandro L

AU - Rekow, E Dianne

AU - Thompson, Van P

AU - Coelho, Paulo G

PY - 2012/8

Y1 - 2012/8

N2 - PURPOSE: The purpose of this study was to test the hypothesis that all-ceramic crown core-veneer system reliability is improved by modifying the core design and as a result is comparable in reliability to metal-ceramic retainers (MCR). Finite element analysis (FEA) was performed to verify maximum principal stress distribution in the systems.MATERIALS AND METHODS: A first lower molar full crown preparation was modeled by reducing the height of proximal walls by 1.5 mm and occlusal surface by 2.0 mm. The CAD-based preparation was replicated and positioned in a dental articulator for specimen fabrication. Conventional (0.5 mm uniform thickness) and modified (2.5 mm height, 1 mm thickness at the lingual extending to proximals) zirconia (Y-TZP) core designs were produced with 1.5 mm veneer porcelain. MCR controls were fabricated following conventional design. All crowns were resin cemented to 30-day aged composite dies, aged 14 days in water and either single-loaded to failure or step-stress fatigue tested. The loads were positioned either on the mesiobuccal or mesiolingual cusp (n = 21 for each ceramic system and cusp). Probability Weibull and use level probability curves were calculated. Crack evolution was followed, and postmortem specimens were analyzed and compared to clinical failures.RESULTS: Compared to conventional and MCRs, increased levels of stress were observed in the core region for the modified Y-TZP core design. The reliability was higher in the Y-TZP-lingual-modified group at 100,000 cycles and 200 N, but not significantly different from the MCR-mesiolingual group. The MCR-distobuccal group showed the highest reliability. Fracture modes for Y-TZP groups were veneer chipping not exposing the core for the conventional design groups, and exposing the veneer-core interface for the modified group. MCR fractures were mostly chipping combined with metal coping exposure.CONCLUSIONS: FEA showed higher levels of stress for both Y-TZP core designs and veneer layers compared to MCR. Core design modification resulted in fatigue reliability response of Y-TZP comparable to MCR at 100,000 cycles and 200 N. Fracture modes observed matched with clinical scenarios.

AB - PURPOSE: The purpose of this study was to test the hypothesis that all-ceramic crown core-veneer system reliability is improved by modifying the core design and as a result is comparable in reliability to metal-ceramic retainers (MCR). Finite element analysis (FEA) was performed to verify maximum principal stress distribution in the systems.MATERIALS AND METHODS: A first lower molar full crown preparation was modeled by reducing the height of proximal walls by 1.5 mm and occlusal surface by 2.0 mm. The CAD-based preparation was replicated and positioned in a dental articulator for specimen fabrication. Conventional (0.5 mm uniform thickness) and modified (2.5 mm height, 1 mm thickness at the lingual extending to proximals) zirconia (Y-TZP) core designs were produced with 1.5 mm veneer porcelain. MCR controls were fabricated following conventional design. All crowns were resin cemented to 30-day aged composite dies, aged 14 days in water and either single-loaded to failure or step-stress fatigue tested. The loads were positioned either on the mesiobuccal or mesiolingual cusp (n = 21 for each ceramic system and cusp). Probability Weibull and use level probability curves were calculated. Crack evolution was followed, and postmortem specimens were analyzed and compared to clinical failures.RESULTS: Compared to conventional and MCRs, increased levels of stress were observed in the core region for the modified Y-TZP core design. The reliability was higher in the Y-TZP-lingual-modified group at 100,000 cycles and 200 N, but not significantly different from the MCR-mesiolingual group. The MCR-distobuccal group showed the highest reliability. Fracture modes for Y-TZP groups were veneer chipping not exposing the core for the conventional design groups, and exposing the veneer-core interface for the modified group. MCR fractures were mostly chipping combined with metal coping exposure.CONCLUSIONS: FEA showed higher levels of stress for both Y-TZP core designs and veneer layers compared to MCR. Core design modification resulted in fatigue reliability response of Y-TZP comparable to MCR at 100,000 cycles and 200 N. Fracture modes observed matched with clinical scenarios.

KW - Computer Simulation

KW - Computer-Aided Design

KW - Crowns

KW - Dental Porcelain

KW - Dental Prosthesis Design

KW - Dental Stress Analysis

KW - Dental Veneers

KW - Finite Element Analysis

KW - Humans

KW - Metal Ceramic Alloys

KW - Survival Analysis

KW - Yttrium

KW - Zirconium

U2 - 10.1111/j.1532-849X.2012.00861.x

DO - 10.1111/j.1532-849X.2012.00861.x

M3 - Article

C2 - 22672220

SN - 1059-941X

VL - 21

SP - 433

EP - 439

JO - Journal of Prosthodontics

JF - Journal of Prosthodontics

IS - 6

M1 - doi: 10.1111/j.1532-849X.2012.00861.x

ER -

Conventional and modified veneered zirconia vs. metalloceramic: Fatigue and finite element analysis

Abstract

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