Estrela Carlos, Bueno Mike R, Barletta Fernando B, Guedes Orlando A, Porto Olavo C, Estrela Cyntia R A, Pécora Jesus Djalma
Department of Stomatologic Sciences, Universidade Federal de Goiás, Goiânia, GO, BR.
Department of Oral Sciences, Universidade de Cuiabá, Cuiabá, MT, BR.
Braz Dent J. 2015 Jul-Aug;26(4):351-6. doi: 10.1590/0103-64402013x0252.
To determine the frequency of apical and cervical curvatures in human molars using the radius method and cone-beam computed tomography (CBCT) images. Four hundred images of mandibular and maxillary first and second molars were selected from a database of CBCT exams. The radius of curvature of curved root canals was measured using a circumcenter based on three mathematical points. Radii were classified according to the following scores: 0 - straight line; 1 - large radius (r > 8 mm, mild curvature); 2 - intermediate radius (r > 4 and r < 8 mm, moderate curvature); and 3 - small radius (r ≤ 4 mm, severe curvature). The frequency of curved root canals was analyzed according to root canal, root thirds, and coronal and sagittal planes, and assessed using the chi-square test (significance at α = 0.05). Of the 1,200 evaluated root canals, 92.75% presented curved root canals in the apical third and 73.25% in the cervical third on coronal plane images; sagittal plane analysis yielded 89.75% of curved canals in the apical third and 77% in the cervical third. Root canals with a large radius were significantly more frequent when compared with the other categories, regardless of root third or plane. Most root canals of maxillary and mandibular first and second molars showed some degree of curvature in the apical and cervical thirds, regardless of the analyzed plane (coronal or sagittal).
使用半径法和锥束计算机断层扫描（CBCT）图像确定人类磨牙根尖和颈部弯曲的频率。从CBCT检查数据库中选取了400张下颌和上颌第一、第二磨牙的图像。基于三个数学点，使用外接圆心测量弯曲根管的曲率半径。根据以下分数对半径进行分类：0 - 直线；1 - 大半径（r > 8 mm，轻度弯曲）；2 - 中等半径（r > 4且r < 8 mm，中度弯曲）；3 - 小半径（r ≤ 4 mm，重度弯曲）。根据根管、牙根三分法以及冠状面和矢状面分析弯曲根管的频率，并使用卡方检验进行评估（显著性水平α = 0.05）。在1200条评估的根管中，在冠状面图像上，92.75%的根管在根尖三分法处呈现弯曲，73.25%在颈部三分法处呈现弯曲；矢状面分析显示，89.75%的根管在根尖三分法处弯曲，77%在颈部三分法处弯曲。与其他类别相比，无论牙根三分法或平面如何，大半径根管的出现频率显著更高。无论分析的是冠状面还是矢状面，上颌和下颌第一、第二磨牙的大多数根管在根尖和颈部三分法处都表现出一定程度的弯曲。
