老年恒牙、年轻恒牙及乳牙釉质磨损性能的体外对比研究

目的探讨并比较各个年龄组人牙釉质磨损行为的异同.方法采用老年恒牙、年轻恒牙及乳牙各8个釉质样本,经体外模拟摩擦试验测得其磨损量,通过测量硬度和断裂韧性以及分析磨斑形貌和釉质中Ca、P、Si元素含量等揭示釉质的摩擦磨损机制.结果老年恒牙、年轻恒牙、乳牙牙釉质磨损量分别为(2.40±1.10)×10-12 m3、(3.50±1.83)×10-12 m3、(4.86±2.49)×10-12 m3,其中老年恒牙磨损明显小于乳牙(P＜0.05),年轻恒牙与乳牙、老年恒牙与年轻恒牙磨损量间差异无显著性(P＞0.05),但三者在机械性能和磨损特征方面均有所不同.结论各年龄组人牙釉质与陶瓷牙对摩时,主要发生磨粒磨损和断裂磨损,各类牙釉质超微结构的差异决定了其抗磨性能的不同.人牙釉质的硬度和断裂韧性测量值与磨损量无对应关系.

Comparative study of friction and wear behavior of different human enamel in vitro

OBJECTIVE: To investigate the friction and wear behavior of different human enamels. METHODS: 24 enamel samples selected from aged, young permanent and faded deciduous teeth were classified into 3 groups and slid against artificial porcelain teeth in the presence of artificial saliva on an oscillating friction and wear test rig. The wear volume loss, microhardness and toughness of each group of the enamel specimens were measured, the wear scars were observed with a scanning electron microscope, and the elemental compositions of Ca, P, and Si of the wear scar and wear debris were determined with an energy dispersion spectrometer. RESULTS: The wear volume losses of aged, young permanent and deciduous tooth enamels are (2.40 +/- 1.10) x 10(-12) m(3), (3.50 +/- 1.83) x 10(-12) m(3) and (4.86 +/- 2.49) x 10(-12) m(3). The data of aged tooth enamels are statistically greater than that of deciduous tooth enamels (P < 0.05). There is no significant difference between the wear volume loss of aged and young permanent tooth enamels or between the young permanent and deciduous tooth enamels (P > 0.05). However, the friction and wear behavior of each group of enamel specimens is different from each other. CONCLUSIONS: In the present testing condition, the wear scars of each kind of enamel specimens is characterized by ploughing and cracking. The different wear resistance of the three kinds of enamels is attributed to the different microstructure of the enamel, while the hardness and toughness of the enamels are not correlated with the wear resistance.