【摘要】 目的:探讨如何在数字化牙片上确定根管工作长度。方法:收集离体前牙99颗(共99个根管)作为研究对象。开髓后,放入牙胶尖至解剖根尖孔处稍后退;使用平行投照法在唇舌向拍摄数字化X线片,标定数字化牙片与牙体的放大比例;在数字化牙片和离体牙上测量牙胶顶点到根尖顶点的距离,观察牙胶顶点在牙体和在牙片上的位置,并比较两者差异。结果:使用平行投照法拍摄数字化X线片,所得牙齿影像与实际牙体的放大比率为1∶1;X线片和离体牙上解剖根尖孔距离根尖顶点的平均距离差异没有统计学意义(P>0.05)。X线片和离体牙上根尖孔的侧方开口率均接近50%,侧方根尖孔与根尖顶点的距离大于正方根尖孔与根尖顶点的距离(P<0.01)。结论:以数字化牙片确定根管工作长度是一种比较准确的方法,但在临床使用时需结合根尖孔与根尖的关系以确定最佳工作长度。更多还原

【Abstract】 Objective: To evaluate the root canal working length measurement on dental digital radiographs,in order to provide reference date for the clinical application. Methods: According to experimental criteria,99 extracted anterior teeth were collected in this study. After opening the pulp chamber,the gutta percha point was fixed in the root canals,with its tip reached the anatomical apical foramens first and then retreated a little. By imitated X-ray parallel techniques,the distance from the top of gutta percha to the apex was measured in the digital images with the software,and compared with the actual length of gutta percha on the extracted teeth through the SPSS 17. 0 software. And these data represented the distance from anatomical apical foramens to apex. Results: Imitated X-ray parallel techniques resulted in almost no magnification. There was no significant difference between the distances from anatomical apical foramen to apex on both X-ray images and the extracted teeth( P > 0. 05). The anatomical apical foramens were both over 50% around apex. The difference between the anatomical apical foramen to apex was longer in the side ones than the vertical ones( P < 0. 01).Conclusions: Direct digital radiography system is reliable in the measurement of root canal working length,but the distance from foramina to the anatomic root apex should be taken into consideration.更多还原