Evaluation of foramen tympanicum using cone-beam computed tomography in orthodontic malocclusions.

The foramen tympanicum is a persistent anatomic formation of the temporal bone due to a defect in ossification normal bone physiology in neonatal or postnatal period. This study determined the occurrence and location of the foramen tympanicum in a Turkish sample using cone-beam computed tomography. Scans of 370 sites in 185 patients were retrospectively analyzed to determine foramen tympanicum occurrence, sizes, and locations according to their orthodontic malocclusions. Measurements were done on axial and sagittal sections to identify the dimensions. Differences in foramen tympanicum incidence by measurements, sex, side, malocclusions, and location were statistically evaluated. Foramen tympanicum was determined in 42 (22.7%) of 185 patients. No statistical difference was found considering location and sex (P > 0.05), but it was found more bilaterally in female patients within significance level at P = 0.024. Mean sizes did not differ significantly by sex but were found to be greater in females. In axial diameter, the average measurement was found wider on the right side of all patients (P = 0.017). The findings showed a greater foramen tympanicum dimension among class II than among class I and III subjects (P < 0.05). Knowledge about these structures is helpful for the interpretation of imaging (especially cone-beam computed tomography) and provides valuable information especially before orthognathic surgery to avoid intraoperative reconstruction and complications.