Morphological changes in the position of the mandibular foramen in dentate and edentate Brazilian subjects.

This study assessed the mandibular foramen (MF) position variability in dentate and edentate Brazilian mandibles. Eighty dentate and 79 edentate mandibles of unknown sex were measured bilaterally using a digital caliper (0.1-mm precision). Horizontal linear measurements (HM) were done from the MF to the anterior border of the mandibular ramus (MF-A) and from the MF to the posterior border of the mandibular ramus (MF-B). Vertical linear measurements (VM) were done from the MF to the most inferior point of the mandibular notch (MF-C) and from the MF to the inferior border of the mandibular ramus (MF-D). Data were analyzed by two-way ANOVA (alpha = 5%). The HM means and standard deviations (+/-SD) for MF-A were, edentate right (ER): 17.5 (+/-3.2) mm, edentate left (EL): 17.4 (+/-3.4) mm, dentate right (DR): 19.2 (+/-3.6) mm, and dentate left (DL): 18.8 (+/-3.8) mm. The means (+/-SD) for the MF-B measurements were, respectively, ER: 12.8 (+/-2.4) mm, EL: 12.9 (+/-2.3) mm, DR: 14.2 (+/-2.4) mm, and DL: 13.9 (+/-2.6) mm. The VM values for the MF-C measurements were, ER: 23.4 (+/-3.8) mm, EL: 22.9 (+/-3.7) mm, DR: 23.6 (+/-3.1) mm, and DL: 23.1 (+/-3) mm, and for the MF-D measurements, ER: 26.4 (+/-4.2) mm, EL: 26.4 (+/-4) mm, DR 28.3 (+/-3.9) mm, and DL 28 (+/-3.8) mm. Side had no influence (p>0.05) on any edentate or dentate mandible measurement. Dentate mandible measurements showed statistically significant differences compared to the edentate mandibles, except for MF-C. The mandibular foramen position changes with loss of teeth and this variability may be responsible for occasional failure of inferior alveolar nerve block.