Abstract: Objective: To compare the friction and wear properties of natural aged teeth with dental restorative materials and to analyze the friction and wear mechanism. Methods: In vitro friction and wear tests were performed between natural teeth collected from patients over 60 years old and pure titanium, zirconia, and glass-ceramic. The surface wear morphology was observed by scanning electron microscope, the surface hardness was measured by micro-hardness tester, and the wear amount was obtained by electronic balance. Results: There were significant differences between three materials and the enamel and dentin (P<0.05). The wear of pure titanium was the closest to that of enamel, and the wear of dentin was significantly higher than that of enamel and three kinds of restorative materials. The wear mechanism of the aged natural tooth enamel was mainly fatigue wear, whereas the dentin was mainly exposed to abrasive wear. Pure titanium was mainly exposed to adhesive and abrasive wear. Abrasive and adhesive wear mainly occurred with glass-ceramic while zirconia was largely exposed to abrasive wear. Conclusion: The wear resistance of pure titanium matches the enamel of natural teeth in old age. The wear resistance of natural teeth enamel is much better than that of dentin. In clinic, according to the wear condition of natural teeth in jaw, it is suggested to rationally select restorative materials, avoiding the excessive wear of natural teeth, especially dentin.

Key words: Wear and friction properties, Natural aged teeth, Dental restorative materials