Wear of denture teeth and their human enamel antagonists

Objectives: To evaluate the wear resistance of artificial denture teeth and their human enamel antagonists in a dual-axis chewing simulator. Method and Materials: Four artificial denture teeth-feldspathic ceramic, nanofilled composite resin, experimental acrylic resin with UDMA/PMMA, and interpenetrating polymer networks (IPN) acrylic resin teeth- were tested in this study. Human enamel cusps were used as antagonists. Wear resistance was analyzed by measuring the vertical substance loss and the volume loss of the denture teeth using a laser scanner after 300,000 chewing cycles. In addition, the vertical substance loss of the antagonists was evaluated using an optical macroscope. Data were statistically analyzed using ANOVA. For qualitative analysis of the wear areas, the teeth were sputter coated with gold and evaluated at magnifications of 50X and 1,000X using SEM. Results: The composite resin teeth exhibited wear that was significantly higher than that of feldspathic ceramic but lower than that of acrylic resin teeth (P .05). Acrylic resin teeth caused no measurable wear on the enamel antagonists. The wear patterns of the feldspathic ceramic and composite resin teeth can be described as attritional, while a fatigue type of wear was observed in the acrylic resin teeth. Conclusion: The lowest total vertical substance loss was found for the combination composite resin-enamel. Based on the results of this study, composite resin teeth seem to be more suitable for dentures opposing natural teeth than ceramic or acrylic resin teeth in terms of wear resistance. Keywords: ceramic teeth, human enamel, laser scanner, nanofilled composite teeth, resin teeth, SEM, two-body wear, Vickers hardness