DIFFERENCES 2 YEARS AFTER TOOTH EXTRACTION IN MANDIBULAR BONE REDUCTION IN PATIENTS TREATED WITH IMMEDIATE OVERDENTURES OR WITH IMMEDIATE COMPLETE DENTURES

In a randomized controlled clinical trial, 74 patients who required im mediate dentures were randomly treated with immediate overdentures on two lower canines or with immediate complete dentures. Mandibular bone reduction was measured by use of oblique lateral cephalometric radiog raphs made at baseline and the results compared with those of one year and two years after denture treatment. Analysis of the data showed th at the average bone reduction in the lower canine regions in the first year was 0.9 mm in the immediate-overdenture group and 1.8 mm in the immediate complete-denture group. In the posterior parts of the mandib le, the bone reductions were, respectively, 0.7 mm and 1.9 mm. The dif ferences were statistically significant in all measured regions. Durin g the second year, no significant differences in bone reduction were f ound. The sums of differences in the first two years were significant in all regions except the molar region, preserving the initial differe nce. Retention of roots of canines beneath a mandibular denture in imm ediate denture patients, even when they were in poor condition, reduce d the collapse of the alveolar processes in all regions of the mandibl e.