GUIDED BONE REGENERATION WITHOUT A MEMBRANE USING ANORGANIC BOVINE BONE. A ONE-YEAR FOLLOW-UP RETROSPECTIVE CASE SERIES

PURPOSE. To evaluate the outcome of horizontal bone augmentation using a periosteal pocket flap after implant placement but no membrane.
MATERIALS AND METHODS. This retrospective case series included eight patients who received 10 implants in total. Guided bone regeneration using anorganic bovine bone and a periosteal pocket flap was performed in areas where the alveolar ridge morphology did not allow for proper implant placement. The buccal periosteum was tightly secured to the underlying bone graft instead of using a membrane. The buccal plate width was measured by two independent periodontists on limited view CBCTs immediately post-operatively, before abutment connection, and 1 year after crown fitting.
RESULTS. No drop-out occurred. All implant sites healed uneventfully and were successfully restored. No complications or failures were observed during the 1-year observation period. The mean preoperative buccolingual bone thickness was 3.5 mm, while the mean bone thickness from the implant shoulder to the buccal plate was 3.7 mm immediately post-operatively, 3.2 mm prior to abutment connection, and 3.1 mm after successful implant restoration; the reduction in bone thickness between immediate post-operative and 1-year time-points was statistically significant at 0.6 mm (P = 0.039). No buccal bone wall deficiency was radiographically detected around any of the 10 implants.
CONCLUSIONS. This retrospective case series demonstrates that it is possible to augment bone horizontally with a granular bone substitute without using a membrane, and that about 22% of the augmented bone is resorbed over the first year.