Jadu Fatima M, Alhazmi Daniah, Badr Fatma F, Jan Ahmed M
Oral Diagnostic Sciences Department, Division of Oral and Maxillofacial Radiology, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
Oral Diagnostic Sciences Department, Division of Oral and Maxillofacial Radiology, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2017 Oct;124(4):413-419. doi: 10.1016/j.oooo.2017.07.006. Epub 2017 Aug 2.
The aim of this study was to objectively quantify the topographic relation of the mandibular canals, impacted third molars, and cortical plates using cone beam computed tomography (CBCT).
A retrospective chart review was conducted using the database of a university-based imaging service. Two calibrated reviewers examined the CBCT images of 100 cases scheduled for mandibular third molar removal. They characterized the position and condition of the mandibular canal and measured its dimensions at 3 different points relative to the third molars.
The mandibular canal is more often located buccal to the third molars but is more likely to be compressed when in a lingual position. The vertical (cephalocaudal) dimensions of the mandibular canal change significantly as the canal progresses toward the ramus. The horizontal (buccolingual) dimensions of the mandibular canal fluctuate very little but significantly narrow in proximity to the third molars. Thinning of the lingual cortical plate is common, whereas grooving of molar roots is uncommon.
Minor variations in the horizontal dimensions of the mandibular canal close to the third molars signify an effect on the canal. This effect may indicate an increased risk of neurovascular injury. The mandibular canal can have a direct or indirect effect on the cortical plates.
本研究的目的是使用锥形束计算机断层扫描（CBCT）客观量化下颌管、阻生第三磨牙和皮质板的地形关系。
使用一家大学影像服务机构的数据库进行回顾性图表审查。两名经过校准的审阅者检查了100例计划拔除下颌第三磨牙患者的CBCT图像。他们描述了下颌管的位置和状况，并在相对于第三磨牙的3个不同点测量了其尺寸。
下颌管更常位于第三磨牙的颊侧，但当处于舌侧位置时更有可能受到压迫。随着下颌管向升支方向延伸，其垂直（头尾）尺寸发生显著变化。下颌管的水平（颊舌）尺寸波动很小，但在靠近第三磨牙处显著变窄。舌侧皮质板变薄很常见，而磨牙牙根出现沟状改变则不常见。
下颌管靠近第三磨牙处水平尺寸的微小变化表明对该管有影响。这种影响可能表明神经血管损伤风险增加。下颌管可对皮质板产生直接或间接影响。
