Mechanical properties of artificial teeth.

In selecting the teeth for fabrication of complete or partial dentures, each patient's anatomic and physiologic requirements and the properties of the artificial teeth themselves should be taken into consideration. The purpose of this study was to evaluate the mechanical properties of the artificial teeth by the static compression test and the impact test. Specimens were the lower first molar porcelain and resin teeth (Livdent FB-20 teeth by G. C. Co., Tokyo, Japan). All were of the same shape. In the static compression test, the fracture load and deformation of the artificial teeth were measured with an Instron-type universal testing machine at a cross-head speed of 1.0 mm/min. Elastic modulus, ultimate strength and absorbed energy were calculated. In the impact test, the acceleration of a falling impactor was measured with a drop impact apparatus. The load applied to the specimen was equivalent to 300N. Absorbed energy and deformation were calculated. The resin teeth showed a lower elastic modulus, higher fracture toughness and shock-absorbing ability than the porcelain teeth. Resin teeth should be selected when the first requisite is high shock-absorbing ability, and porcelain teeth should be selected when the first requisite is high masticating efficiency.