An Investigation Of Bio-Tribological Behavior On Natural Teeth And Prosthetic Materials

The study of tribology has gradually extended to many fields. To be a special friction pair, teeth have some different characteristics from others. As special functional materials, dental prosthetic materials should have not only good mechanical properties, biocompatibility and corrosion resistance, but also excellent tribological performance.To simulate masticatory motion, two-body in vitro wear tests were carried out. The contact is in a ball-on-flat configuration with a reciprocating horizontal tribometer. A normal force of 20 N, reciprocating amplitude of 500 μm, and frequency of 2Hz were used for all the wear tests. Tests up to 5000 cycles were made with artificial saliva bath lubrication. The friction and wear behaviours of natural teeth and dental prosthetic materials were examined by optical microscope, laser scanning microscope and energy dispersive spectroscope. Wear depth was measured by a profilometer. A special attention was paid to the effect of citric acid drink on the wear resistance of natural enamels and plastic teeth. The objective of this paper is to make a theoretical foundation for choosing dental prosthetic materials and clinical treatment for teeth so as to protect the organ of human being and prolong the lifetime of prosthesis.The hardness and the wear resistance of natural teeth gradually decrease from the outer to the inner of corona dentis. Enamel has bettertribological properties than those of enamel-dentinal junction and dentin; The friction and wear behaviors of dental prosthetic materials imply that GAOSI tooth, self-setting dentifrice, copper-base alloy, Ni-Cr alloy and pure Ti are relatively ideal prosthetic materials. When in contact with natural tooth, these materials don' t deteriorate the wear of enamel, but the wear of enamel-dentinal junction and dentin; The citric acid drink evidently reduces the hardness and the wear resistance of enamel, and the surface of enamel is characterized byobvious erosion. But no significant influence of the citric acid is observed on the hardness and wear resistance of plastic teeth.