Effect of Intact Periosteum on Alveolar Ridge Contour Stability after Horizontal Guided Bone Regeneration in the Posterior Region: a Retrospective and Radiographical Cohort Study.

OBJECTIVE: To radiographically evaluate the effect of intact periosteum in guided bone regeneration (GBR) for the treatment of peri-implant ridge defects in posterior region. METHODS: Twenty-eight patients who satisfied the criteria were included in this study. Buccal dehiscence defects were regenerated using demineralised bovine bone mineral (DBBM). Subjects were divided into two groups: the control group (conventional GBR, buccal trapezoidal flap and DBBM with collagen membrane coverage, n = 14) and the test group (modified GBR, buccal pouch and DBBM with collagen membrane coverage, n = 14). CBCT images obtained immediately after and 3 to 7 months following GBR were used to assess buccal bone thickness (BBT) at a level of 0, 2, 4 and 6 mm below the implant platform. RESULTS: Immediately after surgery, BBT at 0 mm and 2 mm below the implant platform presented a significant difference between the two groups (P < 0.05) with significantly thicker buccal bone in the control group in terms of BBT-0 (3.83 +/- 1.01 mm) and BBT-2 (4.88 +/- 1.15 mm) than in the test group (2.33 +/- 0.66 mm and 3.60 +/- 1.10 mm, P = 0.000 and P = 0.008, respectively). After 3 to 7 months of healing, the BBT at all levels showed no significant difference between the two groups (P > 0.05), but more bone graft resorption (BBR) in the control group in terms of BBR-0 (2.45 +/- 1.14 mm), BBR-2 (2.09 +/- 0.94 mm) and BBR-0% (65.37% +/- 26.62%) than the test group (BBR-0 1.07 +/- 0.51 mm, P = 0.001; BBR-2, 1.22 +/- 0.63 mm, P = 0.008; BBR-0% 45.70% +/- 15.52%, P = 0.024). CONCLUSION: In the short term, all treatment modalities achieved similar coronal BBT and the intact periosteum had a positive effect on keeping ridge dimensions even.