锥形束 CT 在正畸牙颌模型分析中的应用

摘要

Objective:To discuss the accuracy of Cone Beam CT in the measurement of dental and jaw model.Methods:30 dental casts were fetched from orthodontic patients with malocclusion deformity in preliminary diagnosis.The plaster models were de-manded to see the teeth and their adjacent teeth clearly.Then all the models were scanned by cone beam CT to reformat the three-di-mensional images.The results of the 3D image were measured and compared with the results from the conventional Manual measure-ment.Results:There was no statistical difference between two methods(P >0.05).The CCC of CBCT measurement and manual meas-urement are in good consistency between 0.883 and 0.999.Conclusion:The 3D digital model of CBCT can be viewed to distinguish point,nest and edge ridge clearly,which can help the operator to identify reliable points.And in a certain degree,it can replace the traditional manual measurement.However,the radiation resistance of the gypsum and the thickness of plaster model may have an effect on the digital imaging.Further research is needed.%目的：探讨锥形束 CT（cone beam CT，CBCT）数字化牙颌模型测量的精确性。方法：对30例正畸初诊患者制取上下颌牙颌阴模一副灌制成阳模，制做成研究模型。对完成的石膏模型要求牙齿完整，牙列清晰，并用锥形束 CT 将所有石膏模型进行扫描，重建石膏模型三维图形，对数字化牙颌模型进行测量，将其结果与传统手工测量结果进行比较。采用配对 t 检验，计算一致性相关系数（concordance correlation coefficient，CCC）及绘制散点图来评价两种方法的一致性。结果：两种测量方法的数据无统计学意义（P ＞0.05），CBCT 测量和手工测量的 CCC 在0.883～0.999之间一致性均非常好。结论：CBCT 三维重建所得的数字化模型清晰，能分辨出明确的尖、窝和边缘嵴，使操作者的辨认选点可靠。在一定程度上可取代传统手工测量，但石膏的放射阻射性能、石膏模型的厚度对石膏牙颌模型的数字化成像可能有影响，有待以后进一步研究。