Su Chi-Chun, Wu Yu-Chiao, Chung Ming-Pang, Huang Ren-Yeong, Cheng Wan-Chien, Cathy Tsai Yi-Wen, Hsieh Chen-Yu, Chiang Ho-Sheng, Chen Ching-Yang, Shieh Yi-Shing
School of Dentistry, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan.
Radiology Division, SongShan Branch, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan.
J Dent Sci. 2017 Sep;12(3):241-248. doi: 10.1016/j.jds.2017.03.002. Epub 2017 Apr 2.
BACKGROUND/PURPOSE: Inadequacy to locate the second mesiobuccal canal (MB2) canal leads to the highest probability of endodontic failure in permanent maxillary first molars (PMFMs) and still remains a constant challenge for many clinicians. The aim of this study was to characterize the geometrical features between MB2 and other orifices of examined PMFMs using cone-beam computed tomography images.
A total of 108 teeth qualified in the cone-beam computed tomography image archives were enrolled in the present study. The intersecting point (T) was determined as the perpendicular line (h, altitude of triangle) projected from the vertex of the MB2 canal orifice to mesiobuccal canal orifice-palatal canal orifice line (MB1-P). We measured the geometric features of PMFMs with the MB2 canal, including the interorifice distances, area, altitude, and the ratio between the canal orifices.
The average interorifice distance was found to be 1.91 ± 0.59 mm for MB1-MB2, 5.73 ± 0.66 mm for MB1-P, and 4.11 ± 0.79 mm for MB2-P, with significant gender difference for MB1-MB2 distance. For the MB1-T distance, a significant difference was found between genders (P = 0.02), with males averaging 1.78 ± 0.07 mm, and females 1.48 ± 0.11 mm. For the MB1-P distance, the majorities of both genders were found in the 20-40% cut-off. A portion of the males exhibited a tendency towards the 40-80% cut-off, while females shifted in the reverse direction towards the 0-20% cut-off.
In clinical scenarios, these anatomical characteristics of the root canals system could be beneficial to locating the MB2 canal.
背景/目的：难以找到上颌第一恒磨牙（PMFMs）的第二近中颊根管（MB2）会导致根管治疗失败的可能性最高，这对许多临床医生来说仍是一项持续的挑战。本研究的目的是使用锥形束计算机断层扫描图像来描述所检查的PMFMs中MB2与其他根管口之间的几何特征。
本研究共纳入了108颗符合锥形束计算机断层扫描图像存档要求的牙齿。相交点（T）被确定为从MB2根管口顶点向近中颊根管口-腭根管口连线（MB1-P）投射的垂线（h，三角形的高）。我们测量了具有MB2根管的PMFMs的几何特征，包括根管口间距离、面积、高度以及根管口之间的比例。
发现MB1-MB2的平均根管口间距离为1.91±0.59毫米，MB1-P为5.73±0.66毫米，MB2-P为4.11±0.79毫米，MB1-MB2距离存在显著的性别差异。对于MB1-T距离，性别之间存在显著差异（P = 0.02），男性平均为1.78±0.07毫米，女性为1.48±0.11毫米。对于MB1-P距离，大多数男性和女性都处于20%-40%的区间。一部分男性有向40%-80%区间偏移的趋势，而女性则向相反方向偏移至0%-20%区间。
在临床情况下，根管系统的这些解剖特征可能有助于定位MB2根管。
