人下颌骨密质骨的复合微动磨损特性研究

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.