Lee Jong-Ki, Ha Byung-Hyun, Choi Jeong-Ho, Heo Seok-Mo, Perinpanayagam Hiran
Department of Oral Pathology, Seoul National University, Seoul, South Korea.
J Endod. 2006 Oct;32(10):941-5. doi: 10.1016/j.joen.2006.04.012. Epub 2006 Jun 30.
In endodontic therapy, access and instrumentation are strongly affected by root canal curvature. However, the few studies that have actually measured curvature are mostly from two-dimensional radiographs. The purpose of this study was to measure the three-dimensional (3D) canal curvature in maxillary first molars using micro-computed tomography (microCT) and mathematical modeling. Extracted maxillary first molars (46) were scanned by microCT (502 image slices/tooth, 1024 X 1024 pixels, voxel size of 19.5 x 19.5 x 39.0 microm) and their canals reconstructed by 3D modeling software. The intersection of major and minor axes in the canal space of each image slice were connected to create an imaginary central axis for each canal. The radius of curvature of the tangential circle was measured and inverted as a measure of curvature using custom-made mathematical modeling software. Root canal curvature was greatest in the apical third and least in the middle third for all canals. The greatest curvatures were in the mesiobuccal (MB) canal (0.76 +/- 0.48 mm(-1)) with abrupt curves, and the least curvatures were in the palatal (P) canal (0.38 +/- 0.34 mm(-1)) with a gradual curve. This study has measured the 3D curvature of root canals in maxillary first molars and reinforced the value of microCT with mathematical modeling.
在牙髓治疗中，根管的入口和预备受到根管弯曲度的显著影响。然而，实际测量弯曲度的研究较少，且大多来自二维X线片。本研究的目的是使用显微计算机断层扫描（microCT）和数学建模来测量上颌第一磨牙的三维（3D）根管弯曲度。提取的上颌第一磨牙（46颗）用microCT进行扫描（每颗牙齿502层图像，1024×1024像素，体素大小为19.5×19.5×39.0微米），并使用三维建模软件重建其根管。连接每个图像层面根管空间中长轴和短轴的交点，为每个根管创建一条虚拟的中心轴。使用定制的数学建模软件测量切向圆的曲率半径并取倒数作为弯曲度的度量。所有根管的弯曲度在根尖三分之一处最大，在中间三分之一处最小。弯曲度最大的是近中颊根（MB）管（0.76±0.48 mm-1），呈突然弯曲；弯曲度最小的是腭根（P）管（0.38±0.34 mm-1），呈逐渐弯曲。本研究测量了上颌第一磨牙根管的三维弯曲度，并强化了microCT结合数学建模的价值。
