Evaluation of location and dimensions of lingual foramina using limited cone-beam computed tomography.

PURPOSE: To assess retrospectively the frequency and location of mandibular lingual foramina and their bony canals with limited cone-beam computed tomography.

PATIENTS AND METHODS: Of 389 consecutively taken cone-beam computed tomograms of the mandible, 191 fulfilled the inclusion criteria of adequate quality, dentate areas within the region of interest, and visualization of the mandibular inferior border. Foramina were located according to tooth areas and were grouped into midline, paramedian, and posterior foramina. Linear measurements included vertical and horizontal diameters of the foramen and its distance to the lower border of the mandible. In addition, the frequency of bony canals originating from lingual foramina was calculated, and the course and anastomoses with other anatomic structures were assessed.

RESULTS: In total, 217 lingual foramina were detected in 1,054 sites. The midline of the symphysis had the highest frequency of foramina (96.2%), with the right first premolar area having the second highest frequency (27.5%). The mean diameter of lingual foramina ranged from 0.97 to 1.20 mm (horizontal diameter) and from 0.90 to 1.01 mm (vertical diameter). Sizes differed significantly between midline and posterior foramina. The mean distance from the foramen to the inferior mandibular border varied from 7.07 to 11.54 mm, with extreme outliers in all 3 groups. Overall, 95.4% of lingual foramina presented with a bony canal originating from the lingual surface, and 40.1% of these canals communicated with other anatomic structures, most frequently with the incisive canal.

CONCLUSIONS: Mandibular lingual foramina and bony canals are frequently present and should be included in presurgical radiographic diagnostics.