Accuracy of periapical radiography, panoramic radiography and computed tomography for examining the mental foramen region

Abstract

Purpose: To determine the accuracy of different radiographic methods for bone height estimation at the mental foramen area. Methods: Twenty dry human hemimandibles were examed by using periapical and panoramic radiography, and computed tomography. An electronic digital caliper was used to measure the tracings obtained from the radiographies in three different times (groups A1, A2 and A3) and in the cross-sectioned hemimandibles (group B). Measurements consisted of: Measure 1 - from the upper limit of the alveolar ridge to the upper limit of the mental foramen; Measure 2 - from the upper limit of the mental foramen to the inferior limit of the cortical bone of the base of the jaw; Measure 3 - from the upper limit of the alveolar ridge to the inferior limit of the cortical bone of the base of the jaw. Data were analyzed with Student-t and Friedman tests. Results: The average difference values in Measure 1 were 0.33 mm, 0.35 mm and 0.85 mm for the periapical radiography, computed tomography and panoramic radiography, respectively (confidence intervals of 0.17 mm to 0.49 mm, 0.18 mm to 0.53 mm and 0.38 mm to 1.32 mm, respectively). Panoramic radiographies showed the greatest differences in Measures 2 and 3, with average values of 1.05 mm and 1.93 mm, respectively. Conclusion: Periapical radiography and computed tomography showed the best accuracy. A safety margin for surgical purposes has been suggested.