Off-axis sliding contact reliability and failure modes of veneered alumina and zirconia

Santana, Tomasa; Zhang, Yu; Guess, Petra; Thompson, Van P.; Rekow, Elizabeth Dianne; Silva, Nelson R.F.A.

doi:10.1016/j.dental.2009.01.093

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Volume 25, Issue 7 , Pages 892-898, July 2009

Off-axis sliding contact reliability and failure modes of veneered alumina and zirconia☆

Tomasa Santana
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, United States
Yu Zhang
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, United States
Petra Guess
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, United States
- Department of Prosthodontics, Albert-Ludwigs-University, Faculty of Dentistry, Freiburg, Germany
Van P. Thompson
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, United States
Elizabeth Dianne Rekow
- New York University, United States
Nelson R.F.A. Silva
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, United States
- Department of Prosthodontics, New York University College of Dentistry, United States
- Corresponding author at: 345 East 24th Street Room 804-S, New York, NY, 10010, United States. Tel.: +1 212 998 9365; fax: +1 2120 995 4244.

Received 28 November 2008; received in revised form 13 January 2009; accepted 14 January 2009.

Abstract

Objective

All-ceramic dental crowns are popular because of their esthetics and biocompatibility. However, they often chip or fracture when subjected to repeated occlusal loading. Considerable efforts to improve the materials are being done through the study of fatigue and failure modes. The vast majority of fatigue studies have been conducted with uniaxial loading and no sliding action. We hypothesized different failure modes for porcelain veneered Y-TZP and that the reliability of porcelain veneered Y-TZP is higher than that of porcelain veneered alumina when subjected to fatigue under 30° off-axis sliding Y-TZP and alumina plates were porcelain veneered and cemented to aged composite blocks as a model for an all-ceramic crown on dentin.

Methods

Specimens (n=21 per group) were fatigue at 30° off-axis with a hard sphere sliding contact in water, by means of a mouth-motion simulator apparatus.

Results

Although no difference between groups was found, the failure modes differed and there was a tendency to higher reliability for Y-TZP compared to alumina for a mission of 50,000 cycles at 150N load.

Significance

Failure modes for alumina specimens were deep penetrating partial cone cracks and cementation internal surface radial cracks. Y-TZP specimens showed only surface damage with deep penetrating partial cone cracks extending to the veneer core interface, with no cementation surface radial cracking, which overall agrees with clinical finding. Angled sliding contact appears to better simulate oral function.

Keywords: Fatigue, Sliding contact, Ceramics, Reliability