Development ofnew three-dimensional jaw bone examination and evaluation systems for the optimum implant selection

本文利用图像分析系统（pQCT）测量了4只猴子下颌无牙颌（M_1P_2P_1|P_1P_2M_1）的骨密度，并对骨体积进行了评价。4只猴子中的3只在拔牙3个月后立即进行骨矿物质密度测量，其中1只在拔牙1、2和3个月后进行测量。虽然pQCT设备的平均摄影误差为2.55%，但其再现精度与常规规格计算机断层扫描相同。手术表现骨质量分级（Lekholm等）与种植体部位骨密度相关系数r=0.78，具有显著相关性（P<0.01）。将骨矿物质密度与三维颌骨检查对种植体放置部位的三维组织学评价进行对比（P<0.05），认为相关性显著，相关系数r=0.64。也就是说，很明显，当松质骨的骨矿物质密度为400-600 mg/cm^3时，骨接触率在50%左右，当骨矿物质密度大于800 mg/cm^3时，骨接触率在60%以上。发展了三维颌骨检查和评估系统，通过改变植入种植体后的加载条件或从现在开始的种植体设计，提示选择与骨质量相对应的最佳种植体。

we measured bone mineral density in the mandibular edentulous jaw (M_1P_2P_1|P_1P_2M_1) of four monkeys, with an image analysis system (peripheral Quantitative Computed Tomography (pQCT) apparatus) for the bone volume evaluation. Three of four monkeys were measured bone mineral density immediately before implant insertion after three months of extraction, one of them were done after one, two and three months of post-extraction.Although the mean of 2.55% of photography errors was occurred by pQCT apparatus, the reappearance accuracy as much as conventional specification computed tomography was obtained. Significant correlation was recognized with coefficient of correlation r=0.78 between the bone quality classification (Lekholm et al.) by operation findings and bone mineral density of implant sites (P<0.01).It is recognized significant correlation with coefficient of correlation r=0.64, as the contrast between bone mineral density and the three-dimensional histologic evaluation of implant placement site by three-dimensional jaw bone examination are carried out (P<0.05). In other words, it is obvious that when bone mineral density of the cancellous bone is 400-600 mg/cm^3, the bone contact ratio is around 50%, when the bone mineral density is more than 800 mg/cm^3, the bone contact ratio be over 60%.The development of three-dimensional jaw bone examination and evaluation systems that give such suggestion that selects an optimum implant corresponding to the bone quality, by changing loading conditions after the insertion of implant or implant design from now on, is produced.