Evaluation of the inferior alveolar canal by cross-sectional hypocycloidal tomography

The aim of this study was to evaluate the possibility of locating the inferior alveolar canal (IAC) before mandibular posterior osteotomy or implant surgery using a computer-controlled hypocycloidal tomographic system. A 1-mm-thick cross section and a 6-mm-thick sagittal tomographic layer were made either through the proposed implant sites or through the center of the mandibular posterior teeth in 55 patients. The system used was a CommCAT IS 2000 tomographic unit in a hypocycloidal motion. The visibility of the location of the IAC was graded as excellent, good, fair, or invisible. In total, 119 sites were assessed. The visibility of the IAC was graded as excellent or good in 74% and fair in 11.7% of the sites. In 14.3% of cases, the canal was graded as invisible. Conventional hypocycloidal tomography has been shown to be a useful radiographic technique for preoperative assessment of the IAC in the posterior mandible.