去除折断种植体部件时种植体的三维有限元热力学分析

摘要

Objective The purpose of the study was to evaluate the distribution of temperature in a dental implant when the fractured components are grinded by high-speed dental handpiece.Methods 3D osseointegration models of the implant and mandible were made by computer-aided design software.In model I,the heating surface was the bottom surface of the implant inner part; in model II,the heating surface was defined as the surface of the implant.The thermal loading types were 50℃-100℃ of constant temperatures with 10-seconds duration.After numerical calculations and post-processing,the temperature distribution of implant had been established.Results In these two models,all of the computed maximum temperatures at P1,P2,and P3 didn't reach 47℃ during the loading time when loading at 50℃.The time of P1 temperature taken to achieve 47℃was about 1 second when loading 80℃,90℃,100v,and the others(P2,P3)were in only a few seconds.In model I,when loading at 60℃,70℃,the maximum temperature at P1 exceeded 47℃,while the others did not exceed 47℃ within 10 seconds.In model II,when loading at 60℃,the maximum temperature at P1,P2 exceeded 47℃ at the 10thsecond,when loading at 70℃,the maximum temperature at P1,P2,and P3 all exceeded 47℃ within 1 second.Conclusion The results suggest that grinding implant components with a high-speed handpiece is a high risky operation,especially as we grind the fractured screw.The clinician should be caution to choose the method and with adequate cooling and intermittent grinding.%目的:应用三维有限元方法分析在使用高速手机去除不同位置的折断种植体部件时,种植体周围牙槽骨的热传导特点及热分布情况.方法:采用三维有限元的方法,建立两个种植体-下颌骨骨结合模型.模型I:加热面为中央螺丝孔的底面;模型Ⅱ:加热面为种植体的表面,给予加热面的热载荷为50℃～100℃持续加热10s.经过数值计算和后处理,分析种植体周围的温度分布.结果:有限元分析结果表明,在两个模型中,加载温度为50℃时,种植体周围温度均小于骨损伤临界温度47℃.当加载温度为80℃、90℃、100℃时,颈部(P1)加热1s可到达47℃,中部和根部(P2、P3)也只需要很短的时间.在模型I中,加载温度为60℃、70℃时,P1点最大温度到达47℃,P2、P3在10s加热并没有到达47℃.在模型Ⅱ中,当加载温度为60℃时,P1、P2点的最大温度在10s时均超过47℃,当加载温度为70℃时,最大温度P1、P2、P3均在1s超过47℃.结论:临床中使用高速手机打磨种植体部件是一个高风险性的操作,尤其是在处理断裂的中央螺丝时.临床医生应谨慎选择此方法,使用时需充足水冷却并间断打磨.