天然牙摩擦磨损的评价

Evaluation of friction and wear behavior on natural teeth

牙体磨损是指牙体在咀嚼和非咀嚼运动过程中,牙面与牙面之间摩擦或牙面与食物之间摩擦导致的牙体硬组织丧失。天然牙磨损从摩擦学角度分为两体磨损、三体磨损、疲劳磨损和化学酸蚀磨损。天然牙摩擦磨损性能研究方法主要有体内临床观察研究、体外试验研究和体内外联合试验研究,而体外试验可以更好地控制试验参数。天然牙摩擦磨损研究又分为摩擦学性能评价以及磨损性能和机制研究两类。学者们有的以体外磨损模拟咀嚼和磨牙症,磨损量用磨损前后质量的丢失进行评价;有的研究了不同年龄段的釉质的耐磨损性能;有的以TA2纯钛球评价了天然牙釉质不同断面的耐磨损性能;有的以纳米划痕技术测量了天然牙各向异性的耐磨损特性;有的以磨斑形貌对磨损机制进行研究。尽管学者们对天然牙摩擦磨损及其机制作了大量的工作,但其结果不尽相同,难以支撑天然牙的磨损失效机制。其失效机制研究的部分缺失,已成为了限制口腔材料发展的关健因素。

Tooth wear is the loss of dental hard tissue caused by the friction between tooth surfaces as well as that between the tooth surface and food when the teeth are in chewing and non-chewing motions. From the perspective of tribology, four types of natural tooth wear exist： two-body, three-body, fatigue, and chemical etching wear. Research methods for the analysis of friction and wear property of natural teeth are primarily clinical studies in vivo, experimental studies in vitro, and experimental studies in vitro and in vivo. In these methods, the test parameters can be adequately controlled by experimental studies in vitro. Research on natural tooth friction and wear is divided into two categories, namely, evaluation of tribological properties and research on wear properties and mechanisms. Several scholars simulated mastication and bruxism through wear in vitro and evaluated the wear amount by the loss of weight. A few focused on the study of the wear resistance of enamel at different ages. Other researchers evaluated the wear resistance of natural enamel at different cross sections with a TA2 titanium ball. Several measured the anisotropy wear resistance of natural teeth by nano- scratch technique, and others studied wear mechanisms by wear scar morphology. The results of these previous studies on the friction and wear of the natural tooth and its mechanisms are inconsistent. Thus, verifying the wear failure mechanisms of the natural tooth is difficult. The incomplete understanding of the failure mechanisms of the natural tooth has become the key factor that limits the development of dental materials.