Three-dimensional alteration of constricted alveolar ridge affected by root thrusting with and without open-flap decortication

Objective: To investigate the morphometric and histological alterations of the constricted alveolar ridge when affected by root thrusting with and without open-flap decortication. Materials and Methods: Eight beagles were divided into three groups: C, control without root thrusting; R, root thrusting only; RD, root thrusting with alveolar decortication. The ridge constriction model was prepared in 16 mandibular quadrants after extraction of the third premolars. Reciprocal root thrusting of the second and fourth premolars was performed toward the constricted ridge for 10 weeks, having a moment of 900 g-mm. Open-flap decortication was conducted on the constricted bone surface in group RD. Micro-CT-based histomorphometric analysis and trichrome-staining-based tissue fractional analysis were performed to evaluate morphometric and microstructural changes on the ridge. Results: Group R revealed a higher percentage of bone volume (P < .001), lower bone mineral density (P < .01), and higher trabecular number (P < .001) than did group C, which was supported by a higher bone fraction woven to lamellar bone (P < .05) resulting from histologic fractional analysis. However, group RD showed no significant difference from group C. Conclusions: Root thrusting toward the constricted ridge induced hypertrophic bone modeling with a high trabecular fraction on the ridge. However, combined open-flap decortication with root thrusting did not improve the volume or quality of the constricted ridge.