Alveolar ridge dimensions in mandibular posterior regions: a retrospective comparative study of dentate and edentulous sites using computerized tomography data.

PURPOSE: To evaluate ridge dimensions at edentulous, mandibular posterior sites, and contralateral dentate sites. METHODS: Computerized tomography scans of 24 patients with one fully edentulous and one fully dentate mandibular posterior region were retrospectively selected. Relative ridge position (rRP), bone height (BH), alveolar canal height (ACH), basal bone height (BBH), and bone width (BW) at 1, 3, and 5 mm apically to the most coronal point of the alveolar crest (BW1mm, BW3mm, and BW5mm, respectively) were measured at posterior dentate sites and contralateral edentulous sites. The proportion of edentulous sites with BH ≥ 9 mm and BW1mm ≥ 6 mm and/or BH ≥ 11 mm and BW3mm ≥ 6 mm was calculated. RESULTS: When compared to dentate sites, edentulous sites showed lower BH, a more apical position of the ridge, lower BW1mm, lower ACH, and similar BBH. The difference in rRP, BH, ACH, BBH, BW1mm, BW3mm, and BW5mm between edentulous and contralateral dentate sites was not significantly different between females and males. The prevalence of edentulous sites with BH ≥ 9 mm and BW1mm ≥ 6 mm and/or BH ≥ 11 mm and BW3mm ≥ 6 mm was higher in females (83.3%) compared to males (58.3%) at second premolar, while was higher in males compared to females at the first molar (83.3 vs 66.6%) and second molar (83.3 vs 75.0%). CONCLUSIONS: In the posterior mandible, edentulous sites show a reduced height and bucco-lingual ridge width compared to contralateral dentate sites. Gender seems to have a limited impact on the extent of ridge resorption following the loss of posterior mandibular teeth.