三种有机酸处理后人牙釉质的磨损性能研究

采用3种不同pH值的有机酸溶液处理成人天然牙试样，以人造瓷牙为摩擦偶件，通过在微动摩擦磨损试验机上模拟人类咀嚼运动，对比考察了天然牙釉质的磨损性能；结合硬度和断裂韧性变化、表面形貌及元素组成分析，探讨了各组酸处理对牙釉质摩擦磨损性能的影响机理。结果表明：除pH=4.0的苹果酸以外，经其他酸以外，经其他酸处理后牙釉质的磨损比经水处理后牙釉质的大；经pH=4.0的苹果酸、柠檬酸和乳酸处理后牙釉质的磨损依次增大；而经pH=2.0的3种酸处理后牙釉质的磨损相差不大。酸处理后牙釉质的磨损形式以磨粒磨损和疲劳断裂磨损为主，不同酸腐蚀对磨屑形成机理和尺寸以及釉质表面硬度影响不同，因而各组牙釉质的磨损不同，当酸性较强时，不同种类的酸对牙釉质磨损影响的差别减弱。

Friction and Wear Behavior of Human Enamel Eroded with Different Organic Acids

The friction and wear behavior of 56 human enamel samples eroded with different organic acids were investigated by sliding against artificial porcelain teeth on an Optimol SRV oscillating friction and wear test rig, using a synthetic saliva as the lubricant medium. The wear volume loss data were analyzed statistically. The wear scars of the enamel of the human tooth observed with a scanning electron microscope and the element concentrations of Ca and P within and out of the wear scars were determined with energy dispersion spectrometry. The correlation among the wear behavior and the hardness and toughness of the enamel samples was discussed as well. As the results, the samples gave higher wear volume loss after eroded with the acids than immersed with distilled water, except that the one eroded with malic acid of pH 4.0 had a smaller wear volume loss. The lactic acid resulted in the largest enamel wear volume loss, followed with the citric acid and malic acid at a pH value of 4.0 (p<0.05), but they showed no significant difference at a pH value of 2.0. The enamels eroded with the organic acids were mainly characterized by abrasive wear and micro cracking. The difference of wear data was attributed to the different corrosive ability of the acids which led to different actions to the mechanical strength of the enamels and had little difference with decreasing pH value. Though the wear resistance of the enamels was related to the hardness and fracture toughness, it might depend on various other factors as well.