下颌骨形态变量的计算机辅助三维测量

Computer-aided 3D measurement of morphological variable of mandible

目的 探讨计算机辅助三维CT重建下颌骨形态变量可视化模型的方法及其可靠性.方法 选取离体成人下颌骨18具.通过拔除颌骨模型上的1颗目标牙进行形态改变;分别记录拔牙前后的下颌骨三维CT数据,通过图形分析软件生成相应的三维数字模型;再通过图形分析软件对所得三维数字模型进行布尔运算,从而实现下颌骨形态变量的可视化模型重建,即目标牙的三维模型.对目标牙三维模型测量结果与手工测量结果进行比较,评价该方法的可靠性.结果 电脑重建目标牙模型所测冠根长度、近远中长度、颊舌向长度分别为（21.62±1.21）、（8.65±0.47）、（8.71±0.70）mm,相应手工实测结果分别为（21.72±1.20）、（8.54±0.37）、（8.87±0.77）mm.冠根长度、近远中向长度和颊舌向长度的电脑测量值与手工实测数值无明显差异（P〉0.05）.结论 以不同时期的模型CT数据为基础,利用计算机软件重建下颌骨形态变量的可视化模型并进行三维测量是一种可靠的颌骨形态变量定量评价方法.

Objective To evaluate the morphological visualization model. Methods computer-aided, 3-dimensionaI-CT measurement in reconstruction of mandibular Mandiblar morphological change model was established by removing one target tooth in 18 adult isolated mandibles. CT scan was performed on the mandibles before and after the tooth extraction, the images were processed in DtCOM format and the 3D model was prefabricated. Through the graphical analysis software,the 3D digital model of 2 Boolean variables was used to rebuild mandible morphological variable visualization model, that was the 3D model of target teeth. The 3D-model measurement of the target tooth was statistically compared with the manual measurement. Results There were no statistical significance between computer measurement and manual measurement both in crown-root length, mesial-distal and buccal-lingual of the teeth by paired T test（P 〉0.05）. Conclusion The reconstruction of mandible morphological variable 3D visualization model is a reliable method for measurement of mandible morphological variables.