Influence of Wearing Artificial Teeth on Horizontal Overlap and Occlusal Surface Fissures

Abstract

Purpose: Artificial teeth that do not compromise masticatory function even after the teeth become worn are necessary to conserve the function of dentures for a long time. The purpose of this study was to observe the morphological changes of artificial teeth by wear, and to discuss the chronological changes of horizontal overlap and fissures.
Methods: Three types of acrylic resin teeth and three types of hard resin teeth were selected as specimens. Artificial teeth were arranged from the first premolar to the second molar, and a sliding test was performed using a mechanical wear testing device up to 80,000 cycles in water with sand at 37°C. Every 10,000 cycles, the projected area of the horizontal overlap, fissure area, and weight were measured. The results (n=5) were analyzed by two-way ANOVA/Tukey's test (p<0.05).
Results: No significant difference was found in the changes in horizontal overlap area between acrylic and hard resin teeth. Fissure area rapidly decreased up to 20,000 cycles, and there were significant differences among all the artificial teeth after 50,000 cycles. Also, with A-Bi, H-Tr and H-En, the horizontal overlap and the fissures were conserved after wear. The rate of decrease in tooth weight varied among the artificial teeth.
Conclusion: The results did not depend on the hardness of the artificial teeth. It is suggested that in artificial teeth that have sufficient horizontal overlap, bucco-lingual diameter and fissures, the horizontal overlap and fissures are conserved after wearing for a long time.