PURPOSE: To identify and quantify the frequency of the projection of the oblique line over the alveolar crests of the mandibular molars in periapical radiographs. METHODS: Five hundred periapical radiographs of the mandibular molar region were selected and evaluated for the presence or absence of the oblique line. When present, its interference on the image of the alveolar crest of the mandibular molars was analyzed. The data obtained was expressed as a percentage of the overlap of the oblique line to the alveolar crests of the mandibular molars. RESULTS: The oblique line was observed in 363 out of the 500 periapical radiographs (72.6%). Out of the 363, 308 (84.8%) showed an overlap of the oblique line over the alveolar crests. However, 55 radiographs (15.1%) did not show such interference. Of the radiographs showing an overlap (308), the incidence of an overlap was 64.6% at a single site (199 radiographs), 33.4% at two sites (103 radiographs), and 1.9% (6 radiographs) at three sites. CONCLUSION: The overlap of the oblique line over the image of the alveolar crests in the mandibular molar region was observed in a significant portion of the total sample.
Crestal bone; alveolar process; mandible
