锥形束CT在下颌第二磨牙C形根管治疗前中后的应用

Application of cone-beam computed tomography during C-shaped root canal therapy in mandibular second molars

下颌第二磨牙C形根管存在根管变异和不规则峡区,容易造成根管清理不彻底和充填不足。锥形束CT(CBCT)可清晰地显示C形根管在矢状面、冠状面和横断面的解剖形态。CBCT空间分辨率高,图像清晰;可选择合适的视野,小视野图像更清晰;可以光盘形式最大限度的保存图像信息,方便临床医生在计算机上多层面、多方位的仔细观察;金属伪影少,辐射剂量低,扫描时间短;所显示下颌第二磨牙C形根管图像的矢状面、冠状面和横断面无前后重叠、无变形和无放大等情况,可为了解下颌第二磨牙C形根管形态提供清晰的三维影像。下颌第二磨牙C形根管预备的难度主要有相对独立的根管间有大量的副根管、交通支和根管弯曲,传统器械难以进入峡区;将显微镜和CBCT共同使用,可提高下颌第二磨牙C形根管的治疗效果。在根管预备前行CBCT检查,可提醒术者避免过度切削并防止侧穿。本文就CBCT在下颌第二磨牙C形根管治疗前中后的应用等研究进展作一综述。

Varied canal morphology and the narrow area of the irregular C-shaped canals in the mandibular second molars can cause incomplete cleaning of the root canal and partial detection of voids in root fillings. Cone-beam computed tomography（CBCT） can clearly display the three-dimensional forms（axial, sagittal, and coronal） of the C-shaped root canal. CBCT presents clear images with high resolution. CBCT can also select the appropriate vision for viewing clear images and can save image information in a optical disc. This technique requires less cupping artifact, low-dose radiation, and short scanning time, and is thus convenient for clinical doctors in carefully performing multi-level and multi-dimensional views on a computer. Panoramic images without distortion and magnification can be generated with the axial, sagittal, and coronal view of the C-shaped root canal in the mandibular second molar. C-shaped root canal treatment in the mandibular second molar is difficult to perform because of the relatively large number of independent root canals, traffic, and root- tube bending, which may impede the entrance of traditional instruments in the gorge area. CBCT combined with a dental operating microscope can improve the effect of the C-shaped root canal treatment on the mandibular second molar. Application of CBCT before root canal therapy can help doctors prevent excessive cutting and side wearing. This article aims to review the applications and research progress with regard to the use of CBCT in the mandibular second molar before C-shaped root canal treatment.