唇腭裂患者牙槽嵴模型三维分析对比方法的初步探讨

Preliminary study on the comparison and analysis of the digital maxillary alveolar casts

目的建立三维数字化系列牙颌模型的对比方法,探讨各变化指标的意义。方法应用同一患者唇裂修复前后的上颌牙颌模型,在三维数字化模型建立的基础上,利用通用逆向工程软件Geomagic7·0进行牙槽嵴模型特征线提取、参考点定位。结果通过模型的参考点定位可建立基准坐标系及基准平面,利用逆向工程软件完成唇裂修复术前后三维数字化牙槽嵴模型的对比流程,包括距离和体积测量,提供了纵向牙槽嵴模型对比研究的可操作平台。结论通过建立三维数字化模型的基准坐标系及基准平面,进行各测量指标的对比,可系统地进行模型的纵向研究,观察其生长发育规律和趋势。

Objective To develop a three-dimensional（3-D） comparison and measuring techniques to analyze changes in palatal forms of the serial maxillary alveolar cast and to evaluate the significance of the different reference change indexes. Methods Following digitizing the casts with a 3-D laser scanner and using reverse engineering software Geomagic Studio 7.0 for a pair of 3-D digital maxillary alveolar cast of an infant of UCLP before and after cheiloplasty, a pair of cast surfaces were reconstructed. The reference points and the character lines were extracted. Results The model coordinate system and the datum planes were established on the basis of reference points extracted. The newly developed analysis technique completed 3-D comparison of palatal forms of UCLP infants before and after cheiloplasty. Distances and volumes changes between the surfaces were determined and expressed graphically. Conclusions With establishing the model coordinate system and the datum plane, it is possible to visualize the comparison outcome of the reference change indexes longitudinally. The various reference change indexes may reflect the trend of the infant maxillary growth.