基于摩擦副理论的齿科陶瓷与天然牙磨损规律及微观机制研究

Because of its good biocompatibility and excellent aesthetic effect, the ceramic restoration has become the main means and method for teeth and dentition defect repair. However, the inherent brittleness of the dental ceramic is easy to cause cracks or peeling.Meantime, high strength ceramic also leads to excessive wear of natural tooth. All the above-mentioned are becoming urgent and important issues in dental prosthodontics. This research based on the "friction pair" theory of the mechanical tribology, to construct the "tooth - dental ceramics" biological friction pair system, with the aid of oral fatigue wear testing machine and 3D Profiling, to get the wear curve of three different wear process between the ceramic and tooth. By using of scanning electron microscope, X-ray diffraction and energy spectrum analysis, focused ion beam, atomic force microscope and other means, the surface morphology, the surface microscopic structure and mechanical properties of characteristics and evolution process of natural teeth and dental ceramics in wear minimum running-in stage, stable wear stage and severe wear stage will be observation and be analysis.The study discusses the bite force, food, temperature, pH value, ceramic surface treatment and other major oral environment factors on the wear behavior influence, constructed four kinds of typical tribological characteristics intrinsic model between the dental ceramic and natural teeth, it can provide the test basis for clinical rational choice and natural tooth wear characteristics matching ceramic restoration, predict the treatment prognosis and improve the property of ceramic materials.

瓷修复体因优良的生物相容性和卓越的美学效果，已成为牙齿牙列缺损修复的主流和发展方向。然而瓷材料固有的脆性导致使用过程中易出现瓷崩裂，高强度瓷材料对天然牙的过度磨耗等，是口腔修复学面临的重要而又亟待解决的问题。本课题引入机械摩擦学中的"摩擦副"理论，构建"天然牙-齿科陶瓷"生物摩擦副系统，借助口腔疲劳磨损实验机和3D形貌轮廓仪获取陶瓷与天然牙之间呈现磨损过程三阶段的磨损曲线，应用扫描电镜、X射线衍射及能谱分析、聚焦离子束、原子力显微镜等手段，对天然牙和齿科陶瓷在磨损的最小跑合期、稳定磨损期及剧烈失效期的表面形貌和亚表层微观组织结构、力学性能的特征及演化过程进行观察分析，探讨咬合力、食物、温度、pH值、陶瓷表面处理等主要口腔环境因素对磨损行为的影响，初步构建四种典型齿科陶瓷与天然牙间的摩擦学特性本征模型，为临床合理选择与天然牙磨损特性相匹配的瓷修复体、预测治疗预后及改进瓷材料性能提供实验依据。

本课题运用机械摩擦学中的摩擦副理论，构建“天然牙-陶瓷修复体”生物摩擦副，采用模拟口腔生物环境条件下的循环磨损方法，借助口腔疲劳磨损实验机、3D 形貌分析仪、扫描电子显微镜等技术手段，研究二体磨损（天然牙-齿科陶瓷）和基于食物磨料的三体磨损（天然牙-食物-齿科陶瓷）在最小跑和期、稳定磨损期和剧烈磨损期等三个不同阶段中，主要影响因素（咬合力、干湿环境、陶瓷表面处理方式、食物类型等）对天然牙与齿科陶瓷材料的宏观和微观磨损特性及内部应力损伤演化特征的影响。结果发现，陶瓷材料在二体和三体磨损环境中均存在“跑合期、稳定磨损期、剧烈磨损期”三阶段；在模拟口腔环境下氧化锆陶瓷自身及对对合材料磨损最小，二硅酸锂铸瓷和白榴石铸瓷磨损量没有明显差异，长石质饰瓷和氟磷灰石饰瓷磨损量最大；二硅酸锂铸瓷在干燥环境下磨损量明显低于水环境下，而水对其他玻璃陶瓷的磨损起到润滑作用；体积磨损量与载荷大小为正相关；表面处理抛光较研磨可以有效降低二硅酸锂玻璃陶瓷的表面粗糙度和磨损量，缩短“跑合期”；饰瓷二体磨损的磨损量和跑合期长度显著大于天然食物磨料存在的三体磨损，而常见食物环境的饰瓷磨损量为 芹菜组>鸡肉组>小米组，异常硬质磨料二氧化硅会造成饰瓷较大的磨损量。研究结果对深入了解齿科陶瓷咀嚼磨损特性，指导临床合理选择与天然牙磨损性能相匹配的瓷修复体，预测瓷修复体治疗预后及改进齿科陶瓷材料性能具有非常重要的意义。