全景片和锥形束 CT 在下颌阻生第三磨牙术前检查中的影像学表现。
Panoramic radiography and cone-beam computed tomography findings in preoperative examination of impacted mandibular third molars.
机构信息
Department of Dentomaxillofacial Radiology, Gazi University Faculty of Dentistry, 82, Sok No: 4 06510, Emek-Ankara, Turkey.
出版信息
BMC Oral Health. 2014 Jun 14;14:71. doi: 10.1186/1472-6831-14-71.
BACKGROUND
Preoperative radiographic examination of impacted mandibular third molars (IMTM) is essential to prevent inferior alveolar nerve injury during extraction. The purpose of this study was to evaluate the correlation between cone-beam computed tomography (CBCT) and digital panoramic radiography (DPR) findings in preoperative examination of IMTM.
METHODS
This retrospective study included 298 teeth in 191 individuals. The relationship between the inferior alveolar canal (IAC) and the IMTM (buccal, lingual, interradicular or inferior), the position of the IMTM with respect to the IAC (contact, no contact), the morphologic shape of the mandible in the IMTM region (round, lingual extended, lingual concave), the type of IMTM (vertical, horizontal or angular) and the number of roots of the IMTM were evaluated on CBCT images. DPR images were evaluated for the number of roots of the IMTM and for the most common radiographic findings indicating a relationship between the IAC and the IMTM (darkening of the roots, diversion of the IAC, narrowing of the IAC and interruption of the white line). Data were statistically analyzed with Cramer V coefficient, Kappa statistic, chi-square and Fisher's exact test.
RESULTS
There was a significant difference in number of roots detected on DPR versus CBCT images. There was a significant association between the type of IMTM and the morphologic shape of the mandible on CBCT images. Darkening of the roots and interruption of the white line on DPR images were significantly associated with the presence of contact between the IMTM and the IAC on CBCT images.
CONCLUSIONS
Panoramic radiography is inadequate, whereas CBCT is useful to detect multiple roots of IMTM. When darkening of the roots and interruption of the white line are observed on panoramic images, there is increased likelihood of contact between the IMTM and the IAC. CBCT is required in these cases.
背景
术前对下颌阻生第三磨牙（IMTM）进行放射学检查对于预防拔牙过程中损伤下牙槽神经至关重要。本研究旨在评估 CBCT 和数字化全景片（DPR）在 IMTM 术前检查中的相关性。
方法
本回顾性研究纳入了 191 名患者的 298 颗牙齿。在 CBCT 图像上评估 IAC 与 IMTM（颊侧、舌侧、根间或下颌）的关系、IMTM 相对于 IAC 的位置（接触、不接触）、IMTM 区域下颌骨的形态（圆形、舌侧延伸、舌侧凹陷）、IMTM 的类型（垂直、水平或倾斜）和 IMTM 的根数。在 DPR 图像上评估 IMTM 的根数和最常见的影像学表现，这些表现提示 IAC 与 IMTM 之间的关系（牙根变暗、IAC 移位、IAC 变窄和白线中断）。采用 Cramer V 系数、Kappa 统计、卡方检验和 Fisher 确切检验对数据进行统计学分析。
结果
DPR 与 CBCT 图像上检测到的根数存在显著差异。CBCT 图像上 IMTM 的类型与下颌骨的形态之间存在显著相关性。DPR 图像上的牙根变暗和白线中断与 CBCT 图像上 IMTM 与 IAC 之间的接触显著相关。
结论
全景片检查不充分，而 CBCT 有助于检测 IMTM 的多个根。当在全景片上观察到牙根变暗和白线中断时，IMTM 与 IAC 接触的可能性增加。在这些情况下需要进行 CBCT 检查。
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