Sawamura Tsuyoshi, Minowa Kazuyuki, Nakamura Motoyasu
Department of Dental Radiology, Dental Hospital, Hokkaido University, Kita-13, Nishi-6, Kita-ku, Sapporo 060-8586, Japan.
Eur J Radiol. 2003 Sep;47(3):221-6. doi: 10.1016/s0720-048x(02)00168-7.
To compare the shapes of roots of impacted teeth shown in three-dimensional computed tomographic images (3D Dental-computed tomography (CT) images) and plain radiographs and to determine whether 3D Dental-CT images are useful for examination before performing an operation for extraction of a maxillary impacted tooth.
Images obtained from patients who had impacted teeth in the maxilla, including impacted mesial supernumerary teeth in 13 patients, impacted incisors in two patients, impacted canines in 11 patients, impacted premolars in four patients and impacted molars in three patients, were used in this study. In all patients, plain radiographs and 3D Dental-CT images were retrospectively reviewed by an oral radiologist for evidence of root dilaceration before operations to extract the impacted teeth were performed. The findings in the images were compared with intraoperative findings in all cases.
The mean specificity and sensitivity of plain radiographs were 95 and 8%, respectively, while those of 3D Dental-CT images were 100 and 77%, respectively. There was a statistically significant (P<0.01) difference between the depiction capabilities of plain radiographs and 3D Dental-CT images with regard to dilacerations of roots of impacted teeth.
CT may enable radiologists to make a quick and accurate diagnosis of tooth impaction. 3D Dental-CT images are useful for determining the root shape of an impacted tooth in the maxilla.
比较三维计算机断层扫描图像（3D口腔计算机断层扫描（CT）图像）和普通X线片中阻生牙的牙根形态，并确定3D口腔CT图像在进行上颌阻生牙拔除手术前的检查中是否有用。
本研究使用了从上颌有阻生牙的患者获得的图像，包括13例患者的近中阻生额外牙、2例患者的阻生切牙、11例患者的阻生尖牙、4例患者的阻生前磨牙和3例患者的阻生磨牙。在所有患者中，在进行阻生牙拔除手术前，由一名口腔放射科医生回顾性地查看普通X线片和3D口腔CT图像，以寻找牙根折裂的证据。将图像中的发现与所有病例的术中发现进行比较。
普通X线片的平均特异性和敏感性分别为95%和8%，而3D口腔CT图像的平均特异性和敏感性分别为100%和77%。在阻生牙牙根折裂的显示能力方面，普通X线片和3D口腔CT图像之间存在统计学显著差异（P<0.01）。
CT可能使放射科医生能够快速、准确地诊断牙齿阻生。3D口腔CT图像对于确定上颌阻生牙的牙根形态很有用。
