Horizontal Maxillary Ridge Augmentation Using Autogenous Bone Blocks With and Without Collagen Membranes: A Randomized Controlled Trial

Objectives: The study aims to investigate the effect of using the collagen membrane with symphyseal onlay blocks for horizontal augmentation of atrophic maxillary alveolar ridges versus uncovered symphyseal onlay blocks. Materials and Methods: 30 patients were randomly and equally allocated into test and control groups. The cortical block was fixed, and an equal mixture of xenograft and autograft particulates was placed to obliterate the gaps. Collagen membranes were used to cover the augmented sites in the test group, whereas they were not used in the control group. Bone thickness was measured at 2 and 5 mm from the crest at 6 months postoperative; bone biopsies were harvested for histomorphometric analysis. Results: The mean horizontal bone gain for the test group at 2 and 5 mm (5.18 ± 0.87 and 5.51 ± 0.83 mm, respectively) was significantly higher than the control group (4.05 ± 0.50 and 4.60 ± 0.69 mm, respectively). The mean graft resorption in the control group was (2.06 ± 0.43 and 1.03 ± 0.50) at 2 and 5 mm, respectively, and both were significantly higher than the test group (1.23 ± 0.46 and 0.74 ± 0.33). The mean bone area percent and the residual graft percent were higher in the test group (58.94% and 14.18%, respectively) than in the control group (43.18% and 3.97%, respectively), p < 0.001. Also, the mature bone percent in the test group (70.85%) was higher than the control group (48.37%), p < 0.001; both differences were statistically significant. Conclusion: Collagen membranes' coverage of symphyseal onlay bone blocks resulted in superior bone quality and quantity for the augmented sites. Trial Registration: ClinicalTrials.gov identifier: NCT04462575.