Damage maps for layered ceramics under simulated mastication

J Dent Res. 2008 Jul;87(7):671-5. doi: 10.1177/154405910808700706.

Abstract

Ceramic restorations, whether monolithic (single layer) or porcelain-veneered, often chip and fracture from repeated occlusal loading. Occlusion involves the opposing tooth sliding along the cuspal incline surface with an applied biting force (off-axis loading). We hypothesized that off-axis contact-load-slide-liftoff fatigue, as compared with normal axial fatigue loading, produces different fracture modes and fatigue lifespans of layered ceramics. Monolithic glass plates were epoxy-bonded to polycarbonate substrates as a transparent model for an all-ceramic crown on dentin. Off-axis and axial (control) cyclic loading was applied through a hard sphere in water, with a mouth-motion machine. The off-axis loading is more deleterious for contact-induced occlusal surface fracture, but less harmful for flexure-induced cementation surface fracture of brittle layers than the axial loading. This is because of the tangential load component associated with the off-axis loading. Clinical relevance is discussed.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Ceramics / chemistry*
  • Crowns*
  • Dental Porcelain / chemistry
  • Dental Restoration Wear*
  • Dental Restoration, Permanent
  • Dental Stress Analysis*
  • Dental Veneers
  • Equipment Failure Analysis
  • Mastication*
  • Materials Testing
  • Molar
  • Shear Strength

Substances

  • Dental Porcelain