WEAR OF ENAMEL BY DENTAL PORCELAIN--EFFECT OF LEUCITE

长期以来，临床医生已经认识到瓷修复体可以 造成大量的磨损和磨损的对立的自然 牙齿结构。文献表明，白榴石的成分 牙科瓷器可能是影响牙齿耐磨性的一个重要因素 瓷器。 这项工作的长期目标是定义组成和 牙科配方中关键的显微结构参数 具有与天然牙齿相匹配的磨粒磨损特性的陶瓷。 这项研究建议的目标是： 1)开发一种专门测量磨损率的测试方法 暴露在牙科瓷器中的天然牙釉质。和 2)评价玉米体位和显微结构变化对玉米生长发育的影响 长石牙科瓷器(特别是白榴石的体积分数) 牙科瓷质与天然牙釉质的磨粒磨损研究。 将使用MLS伺服液压人工嘴来模拟 牙釉质对五种实验瓷的咀嚼作用 组合物和三种市售长石瓷器 产品。实验成分中白榴石的体积分数将 控制在0、10.20、30和40%。与安氏相似的瓷器样本 上中切牙会被天然的下门牙磨损。这个 牙釉质和瓷器样本将测量由于以下原因造成的体积损失 磨料磨损的时间间隔为六个月、一年、两年 以及三年的自然咀嚼活动。体积损失的结果 每种瓷质/牙釉质组合的尺寸将进行比较 统计确定牙釉质的磨损量是否与其体积有关 瓷器中含有少量白榴石。如果中心假设是真的 (即，如果牙釉质的磨损率是体积分数的函数 长石瓷器中的白榴石)，这一新信息将是有用的 在设计具有耐磨性的牙科陶瓷成分时 与对齿结构更相容的特点。

It has been long recognized by clinicians that porcelain restorations can cause a significant amount of wear and abrasion of the opposing natural tooth structure. The literature suggests that the leucite component of dental porcelain may be an important factor in the abrasiveness of dental porcelain. The long term goal of this work is to define the compositional and microstructural parameters which are critical in the formulation of dental ceramics that have abrasive wear properties compatible with natural teeth. The objectives of this research proposal are: 1) to develop a test methodology for specifically measuring wear rates of natural tooth enamel when exposed to dental porcelain. and 2) To evaluate the effect of changes in corn position and microstructure of feldspathic dental porcelain (specifically, the volume fraction of leucite) on the abrasive wear of the dental porcelain against natural tooth enamel. The MLS servohydaulic artificial mouth is to be used to simulate the chewing action of tooth enamel against five experimental porcelain compositions, and three commercially available feldspathic porcelain products. Volume fractions of leucite in the experimental compositions will be controlled at 0, 10. 20, 30, and 40%. Samples of porcelain resembling an upper central incisor will be abraded against natural lower incisors. The tooth enamel and porcelain samples will be measured for volume loss due to abrasive wear at intervals corresponding to six months, one year, two years and three years of natural chewing activity. The results of the volume loss measurements for each porcelain/ tooth enamel combination will be compared statistically to determine if the wear of enamel is dependent on the volume fraction of leucite in the porcelain. If the central hypothesis is true (i.e., if the wear rate of the enamel is a function of the volume fraction of leucite in feldspathic porcelain), this new information will be useful in the design of dental porcelain compositions which have wear characteristics more compatible with the opposing tooth structure.