上颌磨牙近中颊根第二根管口的解剖定位

目的　寻找上颌磨牙近中颊根第二根管 (MB2 )根管口的定位规律。方法　收集离体上颌第一、二磨牙共 5 5 0颗。根管显微镜 (DOM)下探查根管口 ,拍摄髓底图片 ,测量髓底一系列参数 ,分析MB2根管口定位规律。结果　DOM下MB2发现率在上颌第一磨牙和第二磨牙分别为 78.2 4 %和 4 1.32 %。MB2根管口位于MB P根管口连线的近中 ,与该连线的垂直距离在上颌第一磨牙和第二磨牙分别为 0 .6 6mm和 0 .6 3mm ;距近颊根主根管 (MB)根管口距离分别为 1.32mm和 1.2 1mm。结论　建议临床医生在探查上颌磨牙髓底时 ,可在MB P根管口假想连线的近中、距其 0 .5～ 1.0mm ,距MB根管口 1.0～ 2 .0mm ,使MB MB2根管口间假想的、微凸向近中的弧形连线与近中边缘嵴平行处寻找MB2根管口。

Location of the Second Mesiobuccal Canal in Maxillary Molars

Objective To map the location of the second mesiobuccal canal (MB2) orifice. Methods 216 first and 334 second permanent maxillary molars of humans were collected for this study.With naked eyes,access preparation was made and the numbers of canals in each root were recorded. Then, dental operating microscope(DOM) was used to find additional MB2. The teeth with the MB2 locations were photographed through DOM.From these photograph images,several distances were measured and analyzed to map the location of MB2. Results With naked eyes,MB2 were found in 112(51.85%) of the first molars and 79(23.65%) of the second molars; with DOM, among 169(78.24%) of the first molars and 138 of the second molars, MB2 were found. For the first and second maxillary molars,the MB-P distance was 5.88 mm and 4.64mm;MB-MB2 distance was 1.32 mm and 1.21 mm; mesiobuccal line was 0.66 mm and 0.63 mm. Conclusion MB2 orifice was usually located 0.5-1.0 mm mesially from MB-P line,1.0-2.0 mm palatally to MB orifice.