Department of Stomatology, Division of Endodontics and Periodontology, Taichung Veterans General Hospital, Taichung Taiwan.
Department of Stomatology, Division of Endodontics and Periodontology, Taipei Veterans General Hospital, Taipei Taiwan.
J Formos Med Assoc. 2018 Dec;117(12):1086-1092. doi: 10.1016/j.jfma.2017.12.001. Epub 2018 Jan 12.
BACKGROUND/PURPOSE: The purpose of this study is to investigate the prevalence and the morphologic characteristics of the radicular groove and root canal system in human mandibular second premolars with C-shaped root in a Taiwan Chinese subpopulation using cone-beam computed tomographic (CBCT) imaging.
CBCT images of 580 mandibular second premolars were collected from 317 patients. All of the mandibular second premolars were examined in serial axial sections to identify the presence of any C-shaped root and C-shaped canal systems. The morphologic characteristics of mandibular second premolars with C-shaped roots were studied by performing measurements of serial axial sections.
The prevalence rate of mandibular second premolars with a C-shaped root was 3.45% (20/580 teeth) and the rate of those with a C-shaped canal system was 2.24% (13/580 teeth). It was found that 69% of the radicular grooves were located on the lingual half of the root (9/13 teeth) in mandibular second premolars with a C-shaped canal system. In those teeth with a lingual radicular groove, the main canal was toward the buccal side. Frequently, the first C-shaped canal image was found at the mid-root level. The deepest part of the radicular groove was located at about 2.5 mm apical to the first C-shaped canal image.
There was a 2-3% morphologic variation of the mandibular second premolar with a C-shaped root canal system among the Taiwan Chinese subpopulation investigated in this study. Detailed knowledge of the morphological characteristics of teeth may be valuable when choosing clinical treatments.
背景/目的：本研究旨在通过锥形束 CT（CBCT）成像，调查台湾汉族人群下颌第二前磨牙 C 形根管和根管系统的发生率和形态特征。
从 317 名患者中收集了 580 颗下颌第二前磨牙的 CBCT 图像。所有的下颌第二前磨牙均进行了连续轴位切片检查，以确定是否存在 C 形根和 C 形根管系统。通过对连续轴位切片进行测量，研究了具有 C 形根的下颌第二前磨牙的形态特征。
C 形根下颌第二前磨牙的发生率为 3.45%（20/580 颗牙），C 形根管系统的发生率为 2.24%（13/580 颗牙）。研究发现，在具有 C 形根管系统的下颌第二前磨牙中，69%的根管沟位于根的舌侧（13 颗牙中的 9 颗）。在具有舌侧根管沟的牙齿中，主根管朝向颊侧。通常，第一个 C 形根管图像出现在根尖 2.5mm 处。根管沟的最深部位位于第一个 C 形根管图像的根尖 2.5mm 处。
在本研究调查的台湾汉族人群中，下颌第二前磨牙 C 形根管系统的形态变异率为 2%-3%。了解牙齿的形态特征对选择临床治疗可能具有重要意义。
