X线投照角度对诊断下颌第一恒磨牙远舌根变异的作用  

Effect of projecting angles on radiographic diagnosis of the distolingual roots in permanent mandibular first molars

作　　者：顾永春 倪龙兴[2] 

机构地区：[1]吴江区第一人民医院,苏州215200 [2]第四军医大学口腔医学院牙体牙髓科

出　　处：《实用口腔医学杂志》2013年第1期94-96,共3页Journal of Practical Stomatology

摘　　要：目的:探讨X线投照角度对诊断下颌第一恒磨牙远舌根变异的作用。方法:从临床采集29个拔除的3根型下颌第一恒磨牙。X线数字化成像系统拍摄牙齿的颊舌向正位投照片、近远中向邻位片、近中20°及远中20°偏位投照片。以远舌根根尖是否被远颊根影像阻挡为标准,判断不同X线投照角度及投照组合对远舌根的显示效果。结果:远中20°偏位片显示远舌根的效果最佳,显示比例高达89.7%;近中20°偏位片显示比例为27.6%;正位投照片对远舌根显示比例最低,仅为17.2%。同时拍摄近中及远中20°偏位投照片,远舌根的显示比例可以达到100%。结论:临床上,远中20°偏位X线牙片对远舌根的诊断价值最高。Objective： To evaluate the effect of projecting angle on radiographic diagnosis of the distolingual （DL） roots of permanent mandibular first molars. Methods： 29 extracted permanent three-rooted mandibular first molars were used in this study. Radiographs were taken for each specimen by using a radiovisiography system in the bucco-oral and proximal projections, and from a mesial and a distal projecting angle of 20 degrees, respectively. Whether the image of the DL root apex was overlapped by that of the distobuccal root was regarded as the diagnostic criteria. Results ： A distal projecting angle of 20 degrees could best expose the DL root （89, i56% ） , fol- lowed by a mesial projecting angle of 20 degrees （27. 59% ）. The bucco-oral projection resulted in the lowest exposing rate （ 17.24% ）. A mesial 20 degrees project combined with a 20 degrees project produced distal angled radiographs could raise the expo- sing rate to 100%. Conclusion： A distal projecting angle of 20 degrees can best expose the DL root for clinical practice.

关 键 词：下颌第一恒磨牙 远舌根 X线投照角度 

分 类 号：R816.98[医药卫生—放射医学]