Spatial relationship between mandibular third molar and the mandibular canal in cone beam computed tomography. A cross-sectional descriptive study

Background: The spatial relationship between the mandibular canal and the third molar is the three-dimensional position of the mandibular canal with respect to the third molar and is a risk indicator for an injury to the neurovascular bundle in third molar extraction. The aim of this study was to determine the prevalence of the spatial relationship between the mandibular canal and the third molar. Material and methods: A descriptive cross-sectional study was carried out, which evaluated the CBCT files of the anonymized database of the Department of Imaging of the Faculty of Dentistry of the University of Cuenca (Ecuador) within the period 2017-2023. The CBCTs that met the selection criteria were statistically analyzed according to the spatial relationship variable. The CBCTs were examined by the same observer after calibration by a specialist in Dental and Maxillofacial Imaging. Results: 325 lower third molars were evaluated. The highest prevalence of the spatial relationship between the lower third molar and the mandibular canal was the caudal relationship without contact in 32.0 %, followed by the lingual relationship in contact in 22.2 %, buccal in contact in 14.8 %, caudal in contact in 12.9 %, buccal without contact in 8.6 %, interradicular in contact in 6.8 %, lingual without contact in 1.5 % and intrarradicular in contact in 1.2 %. 28.9 % of the third molars presented branches of the mandibular canal. Conclusions: The most prevalent spatial relationship between the mandibular canal and the third molar was the caudal relationship without contact.