Sliding contact fatigue damage in layered ceramic structures.

Abstract

Porcelain-veneered restorations often chip and fracture from repeated occlusal loading, making fatigue studies relevant. Most fatigue studies are limited to uni-axial loading without sliding motion. We hypothesized that bi-axial loading (contact-load-slide-liftoff, simulating a masticatory cycle), as compared with uni-axial loading, accelerates the fatigue of layered ceramics. Monolithic glass plates were epoxy-joined to polycarbonate substrates as a transparent model for an all-ceramic crown on dentin. Uni-and bi-axial cyclic contact was applied through a hard sphere in water, by means of a mouth-motion simulator apparatus. The uni-axial (contact-load-hold-liftoff) and traditional R-ratio fatigue (indenter never leaves the specimen surface) produced similar lifespans, while bi-axial fatigue was more severe. The accelerated crack growth rate in bi-axial fatigue is attributed to enhanced tensile stresses at the trailing edges of a moving indenter. Fracture mechanics descriptions for damage evolution in brittle materials loaded repeatedly with a sliding sphere are provided. Clinical relevance is addressed.

• Authors: J-W Kim, J-H Kim, V P Thompson, Y Zhang
• Journal: Journal of dental research (J Dent Res) Vol. 86 Issue 11 Pg. 1046-50 (Nov 2007) ISSN: 0022-0345 [Print] United States
• PMID: 17959894 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Dental Porcelain

Topics

• Compressive Strength
• Dental Porcelain
• Dental Restoration Failure
• Dental Stress Analysis
• Dental Veneers
• Equipment Failure Analysis
• Glass
• Materials Testing
• Tensile Strength