Gu Liqun, Zhu Chao, Chen Kejia, Liu Xianchu, Tang Zhangui
School of Stomatology, Central South University, Changsha, 410008, Hunan, People's Republic of China.
Department of Oral and Maxillofacial Surgery, Xiangya Stomatology Hospital, Central South University, Changsha, 410008, Hunan, People's Republic of China.
Surg Radiol Anat. 2018 Jun;40(6):609-614. doi: 10.1007/s00276-017-1928-6. Epub 2017 Oct 27.
The positional relationship between the mandibular canal and corresponding third molars is a key anatomic factor of inferior alveolar nerve (IAN) injury. The aim of the present study is to classify the anatomic three-dimensional relationship between the mandibular third molar and the mandibular canal on cone-beam computed tomography (CBCT) images.
This study used CBCT images to classify the positional relationship between the mandibular canal and corresponding third molars. CBCT images of 749 patients (1296 mandibular third molars) were analyzed to draw up a classification.
On a total of 1296 third molars, the mandibular canal relative to the roots of the mandibular third molar was on the apical side (88.1%), followed by the buccal side (7.9%), the lingual side (3.5%), and then between the roots (0.5%). Ninety-five (7.1%) third molars had a close relation with the mandibular canal, while 1201 (92.7%) third molars had no direct contact. The percentage of the mandibular canal contacts with the mandibular third molar was higher when the mandibular canal was lingually positioned.
The anatomic structures of the mandibular third molar and the mandibular canal may be helpful to make adequate surgical planning to avoid or reduce nerve involvement.
下颌管与相应第三磨牙之间的位置关系是下牙槽神经（IAN）损伤的关键解剖因素。本研究的目的是在锥形束计算机断层扫描（CBCT）图像上对下颌第三磨牙与下颌管之间的解剖三维关系进行分类。
本研究使用CBCT图像对下颌管与相应第三磨牙之间的位置关系进行分类。分析了749例患者（1296颗下颌第三磨牙）的CBCT图像以制定分类。
在总共1296颗第三磨牙中，相对于下颌第三磨牙牙根，下颌管位于根尖侧（88.1%），其次是颊侧（7.9%）、舌侧（3.5%），然后是牙根之间（0.5%）。95颗（7.1%）第三磨牙与下颌管关系密切，而1201颗（92.7%）第三磨牙无直接接触。当下颌管位于舌侧时，下颌管与下颌第三磨牙接触的百分比更高。
下颌第三磨牙和下颌管的解剖结构可能有助于制定充分的手术计划，以避免或减少神经受累。
