两种计算机配准方法下的无牙颌印模误差分析

The deviation analysis of edentulous jaw impression using 2 computer registration methods

目的:利用数字化扫描技术和逆向工程软件研究上颌无牙颌的黏膜变化。方法:纳入20例上颌无牙颌患者。使用有孔托盘和藻酸盐材料获取初印模,用模型扫描仪(D810,3shape)对所有印模进行扫描并转化为数字化模型。对模型分别使用“最佳拟合法”和根据分区自行定义的一种新的匹配方法(区域拟合法)配准对齐,计算其偏差结果。采用单因素方差分析(P<0.05)进行统计分析。结果:区域拟合法和最佳拟合法在各区域偏差大小趋势相同,偏差最小的区域分布在牙槽嵴区,偏差最大的区域为后堤区。区域拟合中牙槽嵴偏差(0.129±0.065)mm,后堤区偏差为(0.366±0.154)mm;最佳拟合中牙槽嵴偏差为(0.158±0.052)mm,后堤区偏差为(0.267±0.159)mm。两种方法比较,P<0.05。结论:两种配准方法均证明无牙颌功能性印模具有显著的黏膜下沉变化,不同区域各不相同,区域拟合法提供了口腔模型配准的新思路。

Objective:To study the mucosal changes of maxillary edentulous jaw by using digital scanning technology and reverse engineering software.Methods:20 patients with edentulous maxilla were randomly selected.The primary impression was obtained using a perforated tray and alginate material.All the impressions were scanned with an model scanner(D810,3shape)and converted into digital models.The“best fitting method”and a new matching method(region fitting method)defined according to the partition was used to fit and align the models,the deviation values were calculated.The data were statistically analyzed by on,E-way ANOVA(P<0.05).Results:The trend of deviation between the regional fitting method and the best fitting method was the same in each region.The smallest deviation was located in the alveolar ridge area,and the largest deviation was in the posterior caudal area.In the regional fitting,the deviation of alveolar ridge was(0.129±0.065)mm,and the deviation of posterior embankment was(0.366±0.154)mm;in the best fitting,the deviation of alveolar ridge was(0.158±0.052)mm,and the deviation of posterior embankment was(0.267±0.159)mm(between the 2 methods,P<0.05).Conclusion:The two fitting methods show that the functional impression of edentulous jaw has significant mucosal subsidence changes,which are different in different regions.The region fitting method provides a new idea for oral model alignment.