Retrospective evaluation of the relationship of submandibular fossa depth with mandibular canal and bone thickness using cone beam computed tomography

The aim of this study was to determine the depth of the submandibular fossa (SF) and evaluation of the relationship between the depth of the fossa and bone thickness measured in the buccal and lingual side of the mandibular canal ( MC) in the section where the fossa is deepest, to determine the relationship between SF and the vertical position of the MC and to determine the tooth in line at which the SF is deepest; to evaluate all these parameters according to age, gender and dentition/ edentulousness status in the respective mandibular jaw (right/left jaw). In this study, we retrospectively evaluated 440 cross-sectional images in the right and left mandible, where the SF was deepest, from 1 mm cross-sectional images taken from axial sections of a total of 220 patients, 134 women (60.9%) and 86 men (39.1%). The mean age of the patients was 36.66 ± 13.94 years (minimum 19, maximum 92). The first and second molars of the patients were taken into account and patients with first and second molars were included in the study as 'toothed', patients without both teeth were included as 'edentulous' and patients with one tooth but not the other were included as 'monodentulous'. Of the 440 jaw images of the patients, 283 were evaluated as 'toothed', 75 as 'edentulous' and 82 as 'single-toothed'. SF depth was measured in the cross-sectional section where the fossa was deepest in the CBCT (Cone Beam Computed Tomography) images of the patients. Fossa types were determined. In the cross-sectional section where the fossa was observed to be the deepest, the bone thicknesses in the buccal and lingual part of the MC were measured. The relationship between the measured bone thickness and the depth of the fossa was evaluated. In the cross-sectional section where the deepest point of the fossa was observed, the relationship between the vertical position of the SF and the MC was evaluated. In addition, the tooth alignment of the deepest point of the SF was determined. All these parameters were evaluated according to age, gender and the presence/absence of dentition in the respective mandibular jaw (right/left jaw). In this study, 440 cross-sectional images of the right and left mandibular mandibular half-jaws of 220 patients were evaluated. According to the results obtained; in the right mandible, the mean depth of the SF was 2.44 ± 0.73 mm, the mean value of buccal bone thickness (BBT) was 5.52 ± 1.34 mm and the mean value of lingual bone thickness (LBT) was 2.28 ± 0.83 mm. In the left jaw, the mean depth of the SF was 2.47 ± 0.68 mm, the mean value of the BBT was 5.52 ± 1.33 mm and the mean value of the LBT was 2.26 ± 0.89 mm. SF depth and BBT values in the right and left jaws were found to be higher in males than females. While LBT was found to be higher in females in the right jaw, no significant difference was found between the sexes in the left jaw. The deepest tooth region of the SF RETROSPECTIVE EVALUATION OF THE RELATIONSHIP OF SUBMANDIBULAR FOSSA DEPTH WITH MANDIBULAR CANAL AND BONE THICKNESS USING CONE BEAM COMPUTED TOMOGRAPHY 4 was found at the 2nd molar tooth level in both men and women. When the relationship between the vertical position of the MC and the region where the SF was deepest was examined, it was observed that the MC was in the inferior position in most of the patients. As the depth of the SF increased in the patients, BBT and LBT values decreased. In addition, when the depth of SF was examined according to the dentition status in the right and left jaws, the depth of SF in the right jaw was found to be higher than the depth of SF in edentulous patients, while no significant difference was found between SF depth and tooth status in the left jaw. In our study, the depth of SF was measured deeper in male patients than in female patients. The depth of the SF was measured higher in the toothed jaws than in the edentulous jaws. The deepest area of the SF was found at the level of the 2nd molar tooth in both jaws and in both male and female subjects. As the depth of the SF increased, BBT and LBT values decreased. As the depth of the SF in the posterior region of the mandible increases, the possibility of perforation of the lingual cortical bone increases. This possibility increases especially in surgical interventions to be performed at the level of the second molar tooth. In surgical interventions to be performed in this region, knowing the relationship between anatomical structures (such as MC, SF, length of the bone in the region) will reduce the risk of complications. Considering all these; detailed analysis of the region with CBCT before surgical interventions in the mandibular posterior region will be advantageous in terms of reducing the risk of complications. Keywords: Buccal bone thickness; Cone beam computed tomography; Lingual bone thickness; Mandibular canal; Submandibular fossa