EVALUATION OF PROTECTION HYPOTHESIS FOR COMPOSITE WEAR

北卡罗来纳大学的手术牙科是 最大的后路复合体临床研究中心 最大的复合研究修复体信息数据库(9 涉及26个材料的项目)。我们最近提出的证据表明 (A)后部复合材料的磨损率随着磨损率的增加呈指数下降 时间，(B)患病率和严重程度按部位排列为第一磨牙和第二磨牙； 第二前磨牙和第一前磨牙；(C)广泛或复杂的修复体 更容易受影响。咬合接触区的修复体会磨损 但主要是在无接触区域。我们的结果支持 遵循“保护”假说。产生无接触磨损 口腔内被食物中的0.1um研磨颗粒选择性研磨 复合材料的树脂基质。磨损受到严密防护的限制 填充颗粒与空洞制备壁之间的距离。本地填充物 颗粒间距控制微观磨损保护，而空洞 制备尺寸和位置控制宏观磨损保护。这 假说似乎可以解释大多数研究发表的磨损结果 消息来源。这项提议的目标是用以下方法检验这一假设 不同牙面磨损率和磨痕的临床资料 (咬合、脊槽、面部和舌部、近中)， 不同的牙齿类别(磨牙、前磨牙、门牙)，不同的复合体 类型(常规、混合、微充填)和不同的口腔时间(0- 0.5、0.5-5年和5-10年)。有关磨损率和花纹的临床数据将 与改进的Degee磨损试验的实验室数据进行比较 模拟临床磨损。填料颗粒分布、大小和 将对复合材料的颗粒间距进行表征。 从以前的研究中可以获得长期磨损率数据。初始磨损 将通过插入三个后置复合体来研究速率行为。 磨损模式将用扫描电子显微镜从环氧树脂复制品中进行表征。 局部磨损率将根据林费尔德等级的边际来确定， M-L量表和扫描电子显微镜测量。来自临床评估的信息， 演员收视率和复制品分析将被统计分析以 比较体外磨损和测试“保护”磨损理论。

The Operative Dentistry department at the University of North Carolina is the largest clinical research center for posterior composites and maintains the largest database of information on composite research restorations (9 projects involving 26 materials). We have recently presented evidence that (a) the wear rate of posterior composites decreases exponentially with time, (b) its prevalence and severity by site is 1st molars> 2nd molars> 2nd premolars> 1st premolars, and (c) wide or complex restorations are much more susceptible. Wear occurs on restorations at occlusal contact areas but is predominantly at contact free ares. Our results support the following "protection" hypothesis. Contact free wear is produced intraorally by > 0.1 um abrasive particles in food that selectively abrade the resin matrix of composites. Wear is limited by protection from closely spaced filler particles and from cavity preparation walls. Local filler particle spacing controls microscopic wear protection while cavity preparation size and location control macroscopic wear protection. This hypothesis appears to explain published wear results from most studies and sources. The objective of this proposal is to test this hypothesis with clinical data on wear rates and patterns from different tooth surfaces (occlusal, ridges and grooves, facial and lingual, interproximal), different tooth classes (molars, premolar, incisors), different composite types (conventional, hybrid, microfills), and different intraoral times (0- 0.5, 0.5-5, and 5-10 years). Clinical data on wear rates and patterns will be compared to laboratory data from modified DeGee abrasion tests to simulate clinical wear. Filler particle distribution, sizes, and interparticle spacing will be characterized for composites. Long term wear rate data is available from previous studies. Initial wear rate behaviors will be studied by inserting three posterior composites. Wear patterns will be characterized from epoxy replicas with the SEM. Local wear rates will be determined at margins with the Leinfelder scale, M-L scale, and SEM measurements. Information from clinical evaluations, cast ratings, and replica analyses will be statistically analyzed to compare in vitro wear and test the "protection" wear theory.