Materials design in the performance of all-ceramic crowns

Biomaterials. 2004 Jun;25(14):2885-92. doi: 10.1016/j.biomaterials.2003.09.050.

Abstract

Results from a systematic study of damage in material structures representing the basic elements of dental crowns are reported. Tests are made on model flat-layer specimens fabricated from various dental ceramic combinations bonded to dentin-like polymer substrates, in bilayer (ceramic/polymer) and trilayer (ceramic/ceramic/polymer) configurations. The specimens are loaded at their top surfaces with spherical indenters, in simulation of occlusal function. The onset of fracture is observed in situ using a video camera system mounted beneath the transparent polymer substrate. Critical loads to induce fracture and deformation at the ceramic top and bottom surfaces are measured as functions of layer thickness and contact duration. Radial cracking at the ceramic undersurface occurs at relatively low loads, especially in thinner layers. Fracture mechanics relations are used to confirm the experimental data trends, and to provide explicit dependencies of critical loads in terms of key variables: material-elastic modulus, hardness, strength and toughness; geometric-layer thicknesses and contact radius. Tougher, harder and (especially) stronger materials show superior damage resistance. Critical loads depend strongly (quadratically) on crown net thickness. The analytic relations provide a sound basis for the materials design of next-generation dental crowns.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Biocompatible Materials / chemistry*
  • Ceramics / chemistry*
  • Compressive Strength
  • Crowns*
  • Dental Materials / chemistry*
  • Dental Porcelain / chemistry
  • Dental Restoration Failure*
  • Elasticity
  • Equipment Design / methods
  • Hardness
  • Materials Testing / methods*
  • Surface Properties

Substances

  • Biocompatible Materials
  • Dental Materials
  • Dental Porcelain