Determination of the course of the mandibular canal usingcone beam computed tomography

To determine the course of the mandibular canal and its variations such as bifid mandibular canal with Cone Beam Computed Tomography (CBCT) examinations for order to prevent damage to the inferior alveolar nerve and its branches during dental implant applications and surgical procedures performed in the mandible. This study was performed retrospectively by analyzing the KIBT data of 600 patients admitted to the Department of Periodontology, Faculty of Dentistry, Hacettepe University. The mandibular foramen, mandibular canal (3rd molar, 2nd molar, 1st molar, and 2nd premolar), and mental foramen were analyzed using CBCT images. The diameter of the mandibular and mandibular incisive canal was measured in the buccolingual and apicocoronal directions. The distance of the mandibular canal to the external borders of the mandible and to the tooth apices was recorded. The prevalence of bifid mandibular canal, anterior loop and mandibular incisive canal were evaluated and the location of bifid mandibular canal and mental foramen were classified and reported. The distance of the mental foramen in the apicocoronal direction and its distance to the external borders of the mandible and tooth apices were measured. The 95% confidence interval was used for the significance level. Chi-Square test was used to compare categorical data. Of the 600 patients included in the study, 354 were female and 246 were male. The distance of the mandibular foramen from the mandibular base was recorded as 24.12 mm. 24.7% had a bifid mandibular canal. The most common type of bifid mandibular canal was type 2 with a rate of 38.2%. In our retrospective study, the diameter of the mandibular canal in the apicocoronal and buccolingual direction was 2.65 mm and 2.12 mm, 2.45 mm and 2.02 mm, 2.32 mm and 2.02 mm, 2.35 mm and 2.14 mm in the 3rd molar region, 2nd molar region, 1st molar region, 2nd premolar region, respectively. The most common location of the mental foramen was type 4 (at the level of the 2nd premolar apex) with 54.8%. The prevalence of anterior loop was 25.8%. The average length and caudal distance of the anterior loop was 6.03 mm and 3.67 mm, respectively. The prevalence of mandibular incisive canal was 79.8%. The evaluation of the mandibular region before mandibular surgical interventions, especially using CBCTs, is very CRUCİAL to avoid possible complications during and after the operation. This retrospective study can provide important clinical informationS about the course and variations of the mandibular canal before mandibular surgical interventions. Especially the complex structure of the mandibular posterior region requires extra careful examination before dental implant applicationS. Our study presents the anatomy of this region in detail. Key words: mandibular canal, implant, variation