Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
Division of Endodontics, University of Minnesota School of Dentistry, Minneapolis, MN, USA.
Int Endod J. 2019 Aug;52(8):1218-1227. doi: 10.1111/iej.13109. Epub 2019 Mar 28.
To determine whether a relationship exists between the apical shape of roots and root canal system complexity by performing a micro-computed tomography analysis.
One hundred extracted permanent maxillary first molars were scanned using a micro-computed tomography device at 19.6 μm voxel size. Two groups of mesiobuccal roots were formed according to the root aspect ratio value in the apical 3-mm cross-sectional level ('<2 and ≥ 2.00'). Data were recorded regarding the number and presence of accessory canals and their location, isthmus, presence of the mesiobuccal canal and dentine thickness. Depending on the analysed variable, Mann-Whitney U test and Z-test for proportions were used to compare groups. The significant level was set at 5%.
Mesiobuccal roots with an aspect ratio ≥ 2.00 at the apical 3-mm cross-sectional level had higher percentages of accessory canals, apical foramina and MB2 root canals in the apical 3 mm. The vertical average distance from the accessory foramina and origin from the anatomic apex was 1.40 and 2.19 mm, respectively. Overall, 21.8% of the accessory canals had their origin coronal to a 3-mm root resection line. There was no difference between the groups regarding dentine thickness.
The shape of the apical 3 mm of maxillary first molar mesiobuccal roots was a predictive factor for the presence of complex root canal systems. Roots with a lower aspect ratio had less complex apical anatomy.
通过微计算机断层扫描分析，确定根尖形状与根管系统复杂性之间是否存在关系。
使用微计算机断层扫描设备以 19.6μm 体素大小对 100 颗上颌第一磨牙进行扫描。根据根尖 3mm 横截面水平的根面比（“<2 和≥2.00”）值，将近中颊根分为两组。记录有关副根管数量和存在情况及其位置、峡部、近中颊根管存在情况和牙本质厚度的数据。根据分析的变量，使用曼-惠特尼 U 检验和比例 Z 检验比较组间差异。显著性水平设定为 5%。
根尖 3mm 横截面水平根面比≥2.00 的近中颊根，在根尖 3mm 处具有更高的副根管、根尖孔和 MB2 根管百分比。副根管和起源于解剖根尖的垂直平均距离分别为 1.40mm 和 2.19mm。总体而言，21.8%的副根管起源于 3mm 根切除线的冠方。两组之间的牙本质厚度没有差异。
上颌第一磨牙近中颊根根尖 3mm 的形状是复杂根管系统存在的预测因素。根面比较小的根具有较简单的根尖解剖结构。
