Management of postoperative outcomes of polytetrafluoroethylene membranes in alveolar ridge reconstruction: a systematic review.

Guided bone regeneration (GBR) is a validated technique with satisfactory outcomes during 30 years of follow-up. The use of polytetrafluoroethylene (PTFE) membrane for vertical augmentation has been studied extensively. However, studies have reported exposure rates of up to 31%, there is no consensus on the management of postoperative exposure. The objective of this study was to propose a management approach for postoperative exposure of polytetrafluoroethylene (PTFE) membranes in alveolar ridge reconstruction. MATERIAL AND METHOD: An electronic search in PubMed Central's and additional electronic databases was performed. The search strategy was limited to human studies, full-text English or French articles published from 1990 until april 2023. The extracted data included defect location, membrane type, biomaterials, time to postoperative exposure, and Fontana classification stage. Protocol bias assessment was performed using an adaptation of the QUADAS-2 tool. This review has been registered on PROSPERO (ID: CRD42023445497). RESULTS: A total of 43 articles were found to be eligible, and 11 of these met the predefined inclusion and exclusion criteria. Based on the results of this systematic review, an algorithm for the management of PTFE membrane exposure is proposed. CONCLUSION: Postoperative membrane exposure is not a determining factor for the success of bone grafting. In cases with postoperative complications, the majority of cases still achieved adequate implant-prosthetic rehabilitation. Lastly, this series of 11 articles was insufficient to draw conclusions regarding good practice recommendations. A larger series is required to validate the specific management approaches.

Implant repositioning with segmental osteotomy.

INTRODUCTION: The aim of this study is to assess a pioneering technique for atrophic premaxilla restoration. The objective is to reposition an implant reconstruction zone into a position both anatomically and physiologically suitable for occlusal function. Indeed, unlike the other few articles published on the correctional osteotomy of the implant in an inadequate situation, we have planned here an initially «unsuitable¼ insertion in order to benefit of the available bone mass. MATERIAL AND METHOD: 3 patients aged 14-20 years old (1 woman and 2 men) were operated on at the maxillo-facial department of Lille 2 University Hospital for partial implant-prosthetic rehabilitation on atrophic maxillary and/or mandibular sector. 13 implants were seated (85% in the maxilla) in the native bone then moved subsequently by segmental osteotomy. RESULTS: The patients were assessed both clinically and radiologically according to the functional and aesthetic criteria of implant-prosthetic restoration. Functionally, a biomechanically favourable implant/number of teeth ratio (80%) was achieved, with consistent occlusal relationships (centric positioning of the midline point and absence of crossbite) in 100% of cases. Aesthetically, the screw access hole is systematically non-apparent (100%) but has a prosthetically substituted reduced gingivo-alveolar architecture. DISCUSSION: These observations suggest that implant repositioning with segmental osteotomy allows for atrophic premaxilla restoration in implanted bone volume whatever the initial angulation. Peri-implant aesthetic difficulties are not specific to the technique suggested here but are quite common to all premaxilla reconstruction techniques. Lastly, this group of three patients is not enough to be conclusive, and a larger group would be necessary to validate this type of management.