Clinical evaluation of a ridge augmentation procedure for the severely resorbed alveolar socket: multicenter randomized controlled trial, preliminary results

Objective: To radiographically analyze extraction sites left untreated or treated using a socket preservation technique. Materials and methods: A total of 20 patients scheduled for single extraction in the maxilla from second to second premolar were enrolled in this study. All sites showed a bone defect >5 mm at the buccal wall and no soft tissue recession. At baseline (T0), tooth extraction was performed; subsequently, sites were randomly allocated to the control (CG: left to heal without grafting) or test group (TG: grafted using hydroxyapatite). Two months later (T1), implants were inserted and eventual GBR procedure was performed. Three months later, the definitive crown was placed. Follow up was 24 months (T2). A cone-beam computed tomographic examination (CT) was performed at each time point. At each radiographic analysis, horizontal and vertical widths of the sockets were measured. Comparisons between CG and TG were performed by a Wilcoxon non-parametric test. Results: At the end of the study, no patient dropped out and all implants inserted (10 in each group) resulted integrated. GBR procedures were performed at T1 only in the CG. In the CG, the mean value of the horizontal width in the coronal CT slices was 0.98 mm (+/- 0.37), 7.70 mm (+/- 0.92), 7.45 mm (+/- 0.69) at T0, T1 (after bone regeneration) and T2, respectively. In the TG, the mean value of the horizontal width in the coronal CT slices was 0.96 mm (+/- 0.41), 8.97 mm (+/- 1.91), 9.48 mm (+/- 1.56); at T2, it was 9.52 mm (+/- 1.87) at T0 (pre-and post-socket preservation) T1 and T2, respectively. At each follow up, the mean horizontal bone width in TG was statistically significantly greater than in the control group (P < 0.05). At T0, mean value of the vertical bone defect length (BDL) was 6.93 mm for TG, 6.5 mm for CG. At T1 and T2, mean BDL value was 0 for both groups. Statistically significant difference was not found between TC and CG at any time point (P > 0.05). Conclusions: This randomized controlled trial suggested that in sites with buccal bone defects > 5 mm, the application of HA can minimize alveolar crest resorption following tooth extraction. Furthermore, compared with traditional regenerative procedure carried out following socket healing, this preservation technique seems to result in better horizontal regeneration of the buccal bone wall.