多角度投照技术在上颌第一恒磨牙近颊根管识别中作用的研究

Effects of different angulation radiograph on the recognition of the mesiobuccal root canal of maxillary permanent first molar

目的探讨X线不同投照角度对上颌第一恒磨牙近中颊根双根管的识别作用。方法选取临床拔除的上颌第一恒磨牙40个,在无诊断丝和存在诊断丝情况下分别进行X线投照,从0°到30°每间隔5°拍摄1张,每个牙齿拍摄14张X线片。将离体牙制成透明牙标本以提供金标准确定近颊根根管数目。结果 40个上颌第一恒磨牙MB2的发现率为67.50%;诊断丝投照对根管识别的正确率高于无诊断丝投照;诊断丝近中水平偏移15°与无诊断丝近中水平偏移20°投照具有最好的双根管检出率。结论利用诊断丝及偏移角度X线投照能提高上颌第一恒磨牙近中颊根双根管的检出率。

Objective This study was undertaken to investigate the efficiency of different angulation radiograph in diagnosing twin canals in the mesiobuccal roots of maxillary permanent first molars. Methods Forty extracted maxillary permanent first molars were collected. Two kinds of radiographs were taken of each tooth, and they were periapical radiographs with files or not. 14 photographs were taken of each tooth at 5°intervals between 0°and 30°. The teeth were made into transparent specimens to identify the number of canals in the mesiobuccal roots. Results The percentage of MB2 in the 40 maxillary first molars was 67.50%. The detection rate of MB2 in the periapical radiographs with files was higher than that in the ones without files. The optimum beam angulations in periapical radio- graphs with files and without files were mesio - 15° and mesio -20° respectively. Conclusions Periapical angulated radiographs with or without files in canals are useful for detection and diagnosis of MB2 canals in the maxillary permanent first morlars.