【作者】 周丹；

【导师】 周仲荣；

【作者基本信息】 西南交通大学 ， 材料学， 2006， 硕士

【摘要】 人体天然牙的磨损是无法避免的。研究表明,食物颗粒的硬度对于口颌系统发育有着重要的影响,食物颗粒硬度过小会导致咀嚼功能下降,影响口颌系统结构和功能发育。目前,食物过于细软导致牙列拥挤的人数正不断上升。因此,深入系统地研究食物颗粒特性对牙齿摩擦磨损行为的影响,不仅可以丰富和发展生物摩擦学理论,还可以为口颌系统正常发育及牙齿保健提供理论指导。 本论文选用高硬度的沙子和低硬度的荞麦颗粒作为模拟食物颗粒,每种食物颗粒的粒度分为三个等级,在体外摩擦磨损试验机上采用陶瓷球/牙釉质平面试样接触方式,考察了食物颗粒的粒度与硬度对人牙釉质三体磨粒磨损特性的影响。主要结果和结论如下: 1.当食物颗粒硬度较高时,随着颗粒粒度减小,牙釉质的稳态摩擦系数略有降低,磨损表面形貌逐渐由剥落为主转变为犁削效应;当食物颗粒粒度较低时,随着粒度增加,牙釉质的稳态摩擦系数显著降低,磨损表面形貌由犁削效应转变为轻微擦伤。 2.当食物颗粒粒度相同时,硬颗粒对应的牙釉质稳态摩擦系数高于软颗粒,并且随着粒度减小,二者的差距增大;硬颗粒存在时,牙釉质磨损表面形貌则以剥落和犁削效应为主,磨损严重,而软颗粒对应的釉质磨损表面形貌以擦伤和划痕为主,磨损轻微。 3.和两体直接接触磨损相比,硬度低、粒度小的食物颗粒在摩擦磨损过程中可能有一定的润滑作用,从而减缓人牙釉质的磨损;而硬度高、粒度大的食物颗粒则会加剧人牙釉质的磨损。更多还原

【Abstract】 The wear of human teeth is an inevitable physiological process. Clinical problems due to tooth wear have being increased because people are keeping their own teeth for more years. Understanding of the three-body wear of human enamel would help the clinical treatment for excessive wear of teeth and develop new dental restorative materials.In this paper, the sand and buckwheat were selected as the food particles, the size of which was classified into three grades. The effect of the size and hardness of food particles on the three-body wear of human enamel was investigated under ball-on-flat contact using a reciprocating apparatus. The surface characteristics of samples were examined by micro-hardness tester, optical microscopy (OM) and laser confocal scanning microscope (LCSM). Main conclusions are drawn as follows:1. When the sand particles act as third body, the stable value of friction coefficient decreases a little with the decrease in the size of the particles, and the morphologies of the enamel worn surfaces transform from delamination to ploughing. In addition, When the buckwheat particles act as third body, the stable friction coefficient decreases remarkably with the decrease in the size of the particles, meanwhile, the morphologies of the enamel worn surfaces transformed from ploughing to slight scratch.2. When the size of food particles is similar, the stable friction coefficient is higher under the condition of hard particles than that under the condition of soft particles, which is more and more significant with the size of food particles decreasing. The worn surfaces of enamel are characterized mainly by delamination and ploughing under the condition of hard particles, while slight scratch is dominant on the worn surfaces of enamel under the condition of soft particles.3. Compared with the two-body wear of enamel, the food particles with low hardness and small size may act as solid lubricant and alleviate the three-body wear of enamel, however, the food particles with high hardness and large size could aggravate the three-body wear of enamel.更多还原