表面织构在缓解种植体-基台界面磨损退化中的作用及机制研究

Excessive wear of implant-abutment interface during chewing affects the long-term clinical outcome of dental implant. It is a critical challenge for implant dentistry to understand the anti-wear mechanism and to find an effective way in protecting the interface. Our previous study found that micro dimples on the surface of material might increase lubrication protection, thus reduced the wear of material. However, whether these structures have the similar effect in reducing the wear of implant-abutment interface is still unknown. Therefore in this study, the abutments made of titanium alloy and zirconia are selected as a representative. Micro dimples with different size are built on the materials’ surface using laser ablation method. To reveal the anti-wear mechanism of micro dimples, several physical and chemical properties of the surface and subsurface of the materials are measured and compared before and after wear. According to the wear behavior of textured materials, the texture parameters of micro dimples are selected. With the laser ablation method, micro dimple arrays with optimized size are then fabricated on the lower surface of titanium alloy and zirconia abutment separately. Based on several in vitro experiments such as simulated chewing loading test, the wear behavior, micro-gap, wear debris and micro-leakage of implant-abutment interface can be measured, which will determine the role of micro dimples in reducing the wear behavior of implant-abutment interface, especially the wear process in running-in wear stage. This project will provide a new solution to protect the integrity of the implant-abutment interface. And it will also provide the experimental basis for the development of a novel wear-resistant implant system.

咀嚼作用下种植体与基台界面的磨损退化严重制约着修复治疗的远期效果。深入研究减磨机制，制定行之有效的对抗手段，是目前种植修复领域的关键临床问题。课题组前期研究发现,在材料表面制备规则排列的微观织构能通过增加润滑保护等方式赋予界面抗磨特性。但该法能否缓解种植体-基台界面磨损尚不明确。本项目拟将织构理念引入种植体-基台界面设计中。利用激光在钛合金及氧化锆表面刻蚀微米级织构，通过磨损前后材料表层及亚表层理化性能的表征揭示表面织构减磨机制，筛选出抗磨性能优异的织构尺寸参数。再将尺寸优化的织构制备于两类基台下表面，通过模拟咀嚼循环测试等体外实验，分别从磨损量变化规律、界面间隙增大趋势、磨屑排放及界面微渗漏等方面，探究织构对缓解“纯钛种植体-钛合金/氧化锆基台”界面磨损，尤其是跑合期磨损破坏的作用。本项目为保护种植体-基台界面完整性提供了全新的解决思路，也为日后研发新型耐磨损种植系统提供了实验基础。

口腔内因咀嚼而产生的磨损现象是无法避免的。且钛合金耐磨性较差，种植体与基台界面容易因过度磨损引发材料结构退化，导致机械并发症的同时，也可因大量金属颗粒的剥脱释放而造成周围组织炎症，促进生物学并发症。因此，提升钛合金表面的抗磨性能，制定行之有效的减磨策略是目前临床亟待解决的关键科学问题。本项目聚焦材料表面的拓扑化改性，利用激光刻蚀技术在钛合金表面构建了微米尺度沟槽形织构，分别在干燥环境及生物介质条件下进行摩擦磨损测试，发现织构化钛合金表面的磨损行为明显缓解，摩擦系数降低，磨损量减少，磨面损伤减轻，金属离子释放量也有所下降。结合有限元模拟计算，根据生物润滑膜中应力性质及分布状态，筛选优化出抗磨效应最为明显的织构尺寸参数。通过对织构化钛合金表层及表层下理化性能表征，揭示其减磨机理：1）表面织构能够存储液体介质，磨损过程中便于其进入界面，实现二次润滑及充分保护；2）激光刻蚀及热处理手段促使钛合金表面形成二氧化钛纳米晶体，纳米硬度提高，并向表层下逐渐过渡形成适宜的功能梯度，增强了整体机械性能。同时，基于所构建的口腔生物润滑介质体系，发现细菌代谢产物具有潜在的边界润滑效应。本项目证实了“表面织构提升钛合金减磨抗磨特性”策略的科学性，为磨损界面提供一定保护的同时，有效延缓了组织结构的退化。本项目为保护种植体-基台界面完整性提供了解决思路，也为日后研发更加稳定、耐磨损的新型种植修复结构奠定了实验基础，有望提高种植修复的长期疗效。