Abstract
The purpose of this study is to investigate the influence of two marginal shapes of abutment teeth (shoulder type and chamfer type) on the toughness of all ceramic crowns, by means of finite element method and the model tests.
The following results were obtained;
1. Tensile, bending and shear strengths of the Cerestore materials used in the model tests were higher than those of conventional porcelain materials.
2. In the model tests for breaking loads of all ceramic crowns, the models corresponding to abutment teeth with metal core showed higher effect than those corresponding to vital abutment teeth.
On the marginal difference, the strength of full shoulder types were higher than those of chamfer types in the models corresponding to vital abutment teeth, while there was no significant difference between two types in the models corresponding to abutment teeth with metal core.
3. Using finite element method, there was the heavy tensile stress around the loading point of all ceramic crown with vital abutment teeth, which approximated to tensile strength of Cerestore material, the value was approximately three times of that in abutment teeth with metal core.
