人下颌骨密质骨的复合微动磨损特性研究

针对牙种植体-密质骨界面的微动损伤,采用球/面接触方式研究人下颌骨密质骨在倾斜角为45°、两种载荷水平下的复合微动磨损行为.在分析复合微动的动力学特性的同时,结合光学显微镜(OM)、激光共聚焦扫描显微镜(LCSM)、扫描电子显微镜(SEM)对磨痕形貌进行分析,对磨屑的成分进行了测定.结果表明,下颌骨密质骨的 F-D曲线只有椭圆形和准梯形两种,复合微动最终稳态的F-D曲线均为准梯形;在高载荷的情况下骨组织出现了大量的裂纹及组织碎屑,耗散能则出现了明显的波动;下颌骨复合微动的磨损机制表现为粘着磨损、磨粒磨损、裂纹的扩展及组织碎屑润滑等共同作用的特征.

Research on Composite Fretting Behavior of Human Cortical Bone of Mandibular

Dental implants suffer a great variety of loading modes during normal chewing functions, which will initially cause fretting damages at the bone implant interface and might finally induce the failure of implant. Composite fretting tests of flat cortical bone specimens from fresh human mandible against pure titanium (TA2) ball was carried out on a test rig under laboratory controlled conditions. The imposed tiled angle was 45°, the vertical loads varied from Fmin (= 70 N) to Fmax (= 100 N and 200 N, respectively) at a constant loading speed of 12 mm/min, and the number of cycles varied from 1 to 5×104. Dynamic characteristics of composite fretting tests were recorded by the computer during the tests. After tests, morphologies and wear debris of fretting scars were observed by means of optical microscopy (OM), laser confocal scanning microscopy (LCSM) and scanning electron microscopy (SEM). The compositions of the mandibular cortical bone and wear debris were analyzed by energy dispersive X ray spectrum (EDX). There are only the trapezoid and elliptic mode F-D curves during the composite fretting tests of human mandible cortical bone. The friction energy dissipation varied drastically with the increase of the number of cycles under high load condition. The wear mechanisms of the composite fretting of mandible cortical bone were the combination of the adhesive wear, abrasive wear, cracking and lubrication of the human bone tissue debris.