Niroula Deepa, Dahal Sirjana, Poudel Kalpana, Kumar Singh Ashutosh, K C Krishna
Department of Oral Medicine and Radiology, T.U Teaching Hospital, Maharajgunj Medical Campus, Maharajgunj, Kathmandu, Nepal.
Department of Community Dentistry, T.U Teaching Hospital, Maharajgunj Medical Campus, Maharajgunj, Kathmandu, Nepal.
J Nepal Health Res Counc. 2025 Jun 29;23(1):170-175. doi: 10.33314/jnhrc.v23i01.5607.
An important anatomical factor in injuries to the inferior alveolar nerve is the spatial relationship between the mandibular canal and the corresponding third molars. This study was designed to classify the anatomic three-dimensional relationship between mandibular third molars and the mandibular canal on cone-beam computed tomography mages.
A cross-sectional study was conducted by using CBCT images of 100 individuals visiting the Dental Outpatient Department of X hospital from Jan 2022 - Oct 2022. The images were used to classify the threedimensional relationship between the mandibular canal relative to the roots of the mandibular third molar according to Liqun Gu et al 2018 classification. In this classification, four anatomical positions were considered: buccal, lingual, apical and inter-radicular. The second factor considered was the contact and non-contact relationship between the inferior alveolar nerve canal and the mandibular nerve. The data was analyzed via SPSS version 20. Chi square test was performed to determine the contact relationship of the mandibular third molar root with the mandibular canal.
Most of the mandibular canals observed via CBCT (45.0%) were located on the buccal side of the mandibular third molar followed by the apical side (26.0%), between the roots (23.0%) and very few (6.0%) on the lingual side. A significant association was found between the position of the mandibular third molar and the mandibular canal (p<0.001) when the position was lingual and interradicular.
The findings of this study revealed that the majority of mandibular third molars were located on the buccal side. There was a significant relationship between the position of the mandibular third molar and the mandibular canal.
下牙槽神经损伤的一个重要解剖学因素是下颌管与相应第三磨牙之间的空间关系。本研究旨在通过锥形束计算机断层扫描（CBCT）图像对上颌第三磨牙与下颌管之间的解剖三维关系进行分类。
采用横断面研究方法，使用2022年1月至2022年10月在X医院牙科门诊就诊的100例患者的CBCT图像。根据顾李群等人2018年的分类方法，利用这些图像对下颌管相对于下颌第三磨牙牙根的三维关系进行分类。在该分类中，考虑了四个解剖位置：颊侧、舌侧、根尖和根间。考虑的第二个因素是下牙槽神经管与下颌神经之间的接触和非接触关系。通过SPSS 20版软件对数据进行分析。采用卡方检验确定下颌第三磨牙牙根与下颌管的接触关系。
通过CBCT观察到的大多数下颌管（45.0%）位于下颌第三磨牙的颊侧，其次是根尖侧（26.0%）、根间（23.0%），而位于舌侧的很少（6.0%）。当下颌第三磨牙的位置为舌侧和根间时，发现下颌第三磨牙的位置与下颌管之间存在显著关联（p<0.001）。
本研究结果显示，大多数下颌第三磨牙位于颊侧。下颌第三磨牙的位置与下颌管之间存在显著关系。
