Objectives

To obtain radicular measurements of two separate mesiobuccal (MB) root canals in maxillary first molars using micro-computed tomography (μCT) with customized software.

Materials and methods

Human maxillary first molar MB roots (N = 36) with two separate canals (MB1, MB2) and apical foramina were scanned by μCT and analyzed with Kappa2 software to reconstruct three-dimensional (3D) surface models of roots and canals. These models were sectioned at 0.1 mm intervals perpendicular to the central axis of each canal. Canal widths, 3D curvatures, and surrounding dentine thicknesses were measured concurrently on each section. Dentine thicknesses were analyzed statistically for differences between each direction and the different levels of both canals.

Results

Dentine walls around MB1 were thicker than MB2 (p < 0.05). Thinnest dentine was most often located at disto-inside direction in both canals. Canal widths were significantly smaller in MB2 than MB1 (p < 0.01). Apical constrictions were smaller (p < 0.05) and further (p < 0.05) from the apex in MB2 than MB1. Canal curvatures were greatest in the apical third of both canals (p < 0.001), and they were greater in MB2 than MB1 (p < 0.05).

Conclusions

MB2 canals had shorter lengths, smaller widths, and more severe curvatures and were surrounded by thinner dentine walls. In MB2, apical constrictions were between 1 and 2 mm from the apex, compared to about 1 mm for MB1.

Clinical relevance

These detailed measurements and in-depth 3D analyses of maxillary first molar MB roots with two separate canals and apical foramina provide morphologic references for root canal therapy.

中文翻译：

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显微计算机断层摄影术测量上颌第一磨牙中两个分开的近颊颊管的形态

目标

要使用微计算机断层扫描（μCT）和定制软件，获得上颌第一磨牙中两个分开的近颊颊（MB）根管的放射测量。

材料和方法

 用μCT扫描具有两个单独的牙槽（MB1，MB2）和顶端孔的人上颌第一磨牙MB牙根（N = 36），并用Kappa2软件进行分析，以重建牙根和牙槽的三维（3D）表面模型。这些模型以垂直于每个运河中心轴的0.1 mm间隔进行剖切。同时测量每个部分的运河宽度，3D曲率和周围的牙本质厚度。对牙本质的厚度进行统计分析，以了解每个方向与两条管的不同水平之间的差异。

结果

MB1周围的牙本质壁比MB2厚（p  <0.05）。最薄的牙质最常位于两条管的向内向内。MB2中的运河宽度显着小于MB1（p  <0.01）。 与MB1相比，MB2中的根尖收缩更小（p  <0.05），离顶点更远（p <0.05）。根管曲率在两条根管的根尖最大（p  <0.001），并且在MB2中比在MB1中更大（p  <0.05）。

结论

MB2运河的长度较短，宽度较小且曲率更严重，并且被较薄的牙本质壁包围。在MB2中，根尖收缩距离顶点1至2 mm，而MB1约为1 mm。

临床相关性

这些详细的测量和上颌第一磨牙MB根的两条单独的根管和根尖孔的深入3D分析为根管治疗提供了形态学参考。