植入器械微动磨损、疲劳损伤机理及表面/界面强化机制研究

Aiming at solving the fretting wear and fretting fatigue problems of implant device (for example: dental implant), we are planning to open our project from surface and interface research, which lies on implant/bone interface as well as connecting interface within the implant system. Especially, we will develop hardened surface using plasma technology，following by studying the relationship between fatigue life and micro gap behavior in order to improve the longevity of the implant. ① we will develop physics based models of fretting fatigue-thermodynamic entropy flow-interface features to reveal the dynamic behavior of crack initiation and development. ② we will study the fretting wear and anti-loosing properties of the interfaces in the medical devices, in order to master the relationship between fretting wear and connecting stability as well as crack initiation. ③ We will study the strength effect of surface modification: the durability property of the plasma hardened surface as well as the mechanism. Finally, reliability model will be founded to evaluate the improving function of the implant after plasma harden treatment for fatigue life and mechanical sealing. All these will provide us with practical results and theoretical guide for the development of advanced implant device as well as mechanical connecting components.

对于长期植入器械（如：牙种植体）存在着微动磨损、疲劳寿命待改善的问题，迫切需要探索出有效的技术方案突破表面强化及可靠性设计，特别是解决由于微动磨损引起的机械密封及螺纹连接的松动问题。为此，我们拟从种植体/骨组织界面以及内部的连接界面入手，研究微动磨损、微动疲劳的微观过程，掌握植入器械渐变失效的机制；利用等离子体技术进行原位改性，实现植入器械耐磨损、抗疲劳、长寿命的目标。①利用红外热像技术建立微动疲劳-热力学熵流-表界面显微结构的关系模型，掌握微动疲劳的裂纹萌生、扩展的演化过程。②通过扭矩实验、摩擦磨损实验研究连接界面的微动磨损及防松动特性，掌握微动磨损与螺纹松动和疲劳寿命的关系规律。③通过核心部件原位改性研究植入器械疲劳寿命的变化特征，掌握表面/界面特性影响微动磨损、疲劳寿命的关系规律。通过以上三方面的研究本课题将建立植入器械的可靠性设计方法，丰富和发展机械连接件表面强化和寿命评估理论。

植入器械与骨界面发生微动疲劳、连接部件界面发生微动磨损等破坏现象是齿科植入器械的主要失效形式之一。因此，减小微动、提高齿科植入器械的长期寿命成为这类器械发展的关键。表面改性技术在提高植入器械骨结合率、耐磨损、抗疲劳等方面发挥着关键性的作用。传统的涂层技术由于增加了界面、存在长期脱落的风险而逐渐退出了历史舞台。齿科植入器械各部件的原位改性技术具有从表面到基底成分梯度渐变、长期结合力好等优点，是有效解决植入器械微动损伤的关键技术，逐渐成为了新的发展趋势。本研究发现，对种植体表面进行等离体子氧化处理使其具有超亲水特性可以有效提高骨结合率和种植体-骨界面的稳定性，减少种植体失效的发生。对植体螺丝表面进行等离子渗氮处理可以减少螺丝表面磨损，降低螺丝松动，以及提高种植体系统的疲劳寿命。另外，本研究对植体关键部件的微动损伤机制提供了理论依据。