Anatomic variations and lesions of the mandibular canal detected by cone beam computed tomography

The mandibular canal is a significant anatomical structure in implant dentistry, and cone beam computed tomography (CBCT) is an important diagnostic image modality in this field of dentistry. The aim of this study was to evaluate the frequencies of anatomic variations and lesions affecting the mandibular canal in CBCT images of the mandible produced for dental implant planning.

This cross-sectional study evaluated a sample of 250 CBCT examinations (500 mandibular canals). The inclusion criterion was CBCT examinations of the mandible requested for dental implant planning. The presence of anatomic variations and lesions affecting the mandibular canal was evaluated in the CBCT examinations. Moreover, the buccolingual position of the mandibular canal was evaluated in the molar region and in the ramus region. The CBCT exams were evaluated by one observer. The data were analyzed using descriptive and analytical statistics. The one-way ANOVA test was employed to compare the age between the anatomic variations. A paired t test was used to compare the buccolingual position between the molar region and the ramus region. Differences were considered significant when p values were lower than 0.05.

The anatomic variations detected were large-diameter mandibular incisive canal (51.6 %), ramification (12 %), and accessory mental foramen (3.2 %). No difference was observed in the age of the patients between the anatomic variations (p > 0.05). The identified lesions included hypomineralization of the canal walls (20.8 %), idiopathic osteosclerosis (8.8 %), osteolytic lesions (3.2 %), iatrogenic perforation of the mandibular canal (2.8 %), and fibro-osseous lesions (1.6 %). The distance between the mandibular canal and the vestibular cortical bone was higher in the molar region than in the ramus region (p < 0.05).

Anatomic variations and lesions affecting the mandibular canal were common findings in the CBCT images of the mandible produced for dental implant planning. An awareness of these alterations is important for dentistry because some of them might require treatment, change oral surgery planning and difficult inferior alveolar nerve anesthetic block.