Effect of restorative materials on cuspal flexure

The purposes of this study were (1) to establish a methodology for determining surface strains in two locations ofthc same tooth under intact, prepared, and restored conditions and(1) to compare the effects on stiffness of different restorative materials in a tooth subjected to cuspal loading. Two linear strain gauges were tnounted on each of 30 extracted maxillary premolar teeth. Teeth were mounted in poly(methyl methacrylate) resin and randomly ussigned to one of three study groups according to the restorative material and application technique to be used. Statistical analysis indicated a statistically significant interaction between restorative material and tooth condition at both proximal and buccal sites and a statistically significant difference in stiffness between teeth restored with Tenure/Marathon V and those restored with either amalgam or Seotchbond 2/P-50 at the proximal site. Results suggest that the methods employed provide a useful, nondestruetive means of testing the same tooth under various conditions.