利用CBCT对下颌骨切牙管的检出及对临床意义的探讨

目的 利用锥形束CT（CBCT）在活体上实现下颌切牙管（MIC）的检出和定位，并探讨其临床意义。 方法 从医院放射科CBCT数据库中，筛选符合标准的18～85岁个体。在研究对象的CBCT图像上，识别44～34根尖下方的MIC，确定可视性，测量MIC直径及到多个解剖标志的距离。 结果 第一前磨牙和尖牙区MIC可视性明显优于切牙区。下颌骨横断面上MIC多走行于垂直向中1/3段中线偏唇/颊侧。随着向正中联合部延展，MIC直径逐渐变小，绝大多数在切牙区变为不可见。 结论 MIC的临床意义可能没有想象中的重要。术前告知MIC损伤和神经功能障碍的风险是必需的，但更多是基于法律和伦理上的考虑。术前个性化三维图像检查和测量、以及术中尽量避开MIC中的血管神经束，仍是基本的临床要求。

Detection of mandibular incisive canal by cone beam CT and discussion of its clinical significance

Objective To detect and locate mandibular incisive canals (MICs) on 3 dimension images scanned from cone beam computerizing tomography (CBCT) in vivo, and to discuss its clinical significance. Methods Based on an in out standard, a sample was screened out of the CBCT databank of radiology department in our hospital, which involved a part of individuals at the age of 18 to 85. Teeth of 44~34 were selected as the sites of our study. Beneath them MICs were distinguished, of which the visibilities were decided, and the diameters and distances to some anatomic landmarks were measured. Results The visibility of lower first premolar and canine obviously excelled incisors. Most MICs stretched their ways slightly nearer to the buccal or labial cortex in the perpendicular middle third of mandible in the cross sectional images. The diameters of MICs became thinner while running closer to the mental symphyseal region, and mostly invisible below incisors. Conclusions Clinical significance of MICs may not be so important as assumed. It is essential to inform of MICs damage and nerve dysfunction risks before surgical operations, however, which is taken into account grounded on ethicality and forensicality. Customized preoperative 3D image examinations and measurements, and avoidance from MIC injury as much as possible, are still basic clinical requests.