IN VIVO/IN VITRO WEAR PERFORMANCE OF POSTERIOR COMPOSITE

本建议的目的是探讨主要磨损 实验牙科复合材料的机制。 8实验 含有bisGMA/TEGDMA或 UEDMA/-TEGDMA作为基质，60体积%的石英或钡填料颗粒， 和两种不同的硅烷化程序将准备，分析， 在体内和体外条件下测试。 经过初步 两种树脂体系的表征， 材料将被确定。 此外，质量和 将进行硅烷化效果的定量分析。 这些研究之后将进行压缩性的体外评价。 强度、弯曲强度、韧性和耐磨性。 将使用磨损试验进行体外磨损评价 机器（deGee等人，1986）和标准金相抛光 机器（Jorgensen，1980）。 机械性能和磨损率将 在三种老化条件下测定：1）在干燥器（37 2）在蒸馏水（37摄氏度）中，和3）在人工 唾液（37摄氏度）长达三年。 填料浸出 水分子从蒸馏水中的扩散速率和扩散系数 和人工唾液也将被测定。 在确保八种实验性复合材料已经完成之后， ADA规范第27号的要求， 将对复合材料进行评价。 两项体内研究将 在佛罗里达大学的64名患者中进行， 在比利时鲁汶大学。 一位美国牙医和一位 比利时牙医将在每个国家治疗32名患者。 I类 将在上颌和下颌第一磨牙中放置矫正器。 由于磨损造成的材料损失将使用三种不同的 6个月、12个月、24个月和36个月后的评估技术。 与这些 临床评价，将有可能确定：1）是否 不同人口群体之间的饮食差异导致 磨损率的显著差异，2） 不同的牙医可能导致临床磨损的差异 性能，以及3）磨损评估方法是否存在差异， 临床样本导致显著不同的磨损结果。 还将确定是否存在强相关性之间的任何 研究的性能（包括体外磨损）和临床 磨损率 此外，含有60体积%的填料的实验材料具有 平均粒径约为0.2、1、5和10 μ m， 研究了它们的体外耐磨性。 的目标 这部分的研究是为了确定填料间距对 磨损率

The objective of this proposal is to explore the principal wear mechanisms of experimental dental composites. Eight experimental light-cured composites which contain either bisGMA/TEGDMA or UEDMA/-TEGDMA as matrices, 60 vol% of quartz or barium filler particles, and two different silanization procedures will be prepared, analyzed, and tested under in vivo and in vitro conditions. After an initial characterization of the two resin systems, the degree of conversion of the materials will be determined. In addition, qualitative and quantitative analyses of silanization effectiveness will be performed. These studies will be followed by in vitro evaluations of compressive strength, flexural strength, toughness and wear of the composite systems. The in vitro wear evaluation will be conducted using a wear testing machine (deGee et a/., 1986) and a standard metallographic polishing machine (Jorgensen, 1980). Mechanical properties and wear rate will be determined for three aging conditions: 1) dry storage in a desiccator (37 degrees C), 2) in distilled water (37 degrees C), and 3) in artificial saliva (37 degrees C) for periods up to three years. Filler leaching rates and diffusion coefficients of water molecules from distilled water and artificial saliva in these materials will also be determined. After ensuring that the eight experimental composites have fulfilled the requirements of ADA Specification No. 27, in vivo wear resistance of the composites will be evaluated. Two in vivo investigations will be conducted using 64 patients at the University of Florida and 64 patients at the University of Leuven, Belgium. One American dentist and one Belgian dentist will each treat 32 patients in each country. Class I restorations will be placed in maxillary and mandibular first molars. The material loss due to wear will be determined using three different evaluation techniques after 6, 12, 24, and 36 months. With these clinical evaluations, it will be possible to determine: 1) whether differences in diet among different population groups result in significant differences in wear rate, 2) whether restorations made by different dentists are likely to result in differences in clinical wear performance, and 3) whether differences in wear evaluation methods for the clinical specimens result in significantly different wear results. It will also be determined whether strong correlations exist between any of the investigated properties (including in vitro wear) and the clinical wear rate. In addition, experimental materials containing 60 vol% of filler with mean particle diameters of approximately 0.2, 1, 5 and 10 mu-m will be investigated regarding their in vitro wear resistance. The objective of this part of the study is to determine the influence of filler spacing on wear rate.