Extended Platelet-Rich Fibrin as a Membrane for Lateral Window Sinus Lifts: A Case Series

Introduction: Platelet-rich fibrin (PRF) is being increasingly utilized in surgical procedures due to various improvements in clinical outcomes. More recently, a heating process to denature albumin in the platelet poor plasma (PPP) layer has been shown to extend the resorption time of PRF from a typical 2-week period to 4-6 months. Because of its > 4 month resorption properties, extended PRF (e-PRF) membranes have been used in dentistry as an alternative to collagen membranes in alveolar ridge preservations, ridge augmentations, soft tissue grafting, and as a barrier membrane in lateral sinus grafting procedures. Materials and Methods: A total of 22 patients from 3 different clinical facilities participated in this multicenter case series study. All clinicians completed a standard lateral window sinus technique with sticky bone utilizing allograft, xenograft, or autologous dentin with an e-PRF membrane utilized for sole coverage of the lateral window. The survival rate at second stage implant surgery (similar to 6 months) and radiographic analysis determined on consecutive radiographs: (1) the mean residual bone height (RBH) under the maxillary sinus at implant placement and (2) the change in endosinus bone level, were calculated to assess the endosinus bone changes at 6 months. Results: Between June 2022 and December 2023, 22 patients were included in this study. Patients included 12 women and 10 men with a mean age of 58.8 years, ranging from 32 to 78 years. In 22 lateral window sinuses completed, a total of 31 implants were placed. All patients healed uneventfully without any post-operative complications. Post-op CBCTs were taken at 6 months to demonstrate successful sinus floor augmentation and to calculate endosinus gain. No soft tissue invagination was encountered in any of the study participants nor displacement of the graft material into the buccal mucosa. In one case highlighted in this study, the e-PRF membrane was utilized to repair a sinus perforation. The average 6-month post-operative sinus height was 12.3 mm with a mean change in endosinus bone gain of 8.0 mm. Conclusion: Utilizing extended-PRF membranes in place of collagen membranes for coverage of the lateral window during sinus floor elevation was shown to be a successful treatment modality in this case series. These findings provide new opportunities utilizing denatured albumin membranes in implant dentistry and paves the way for additional applications. The material is 100% autologous, low cost. This is the first case series study highlighting its novel use for coverage of the lateral window during sinus grafting. Larger longitudinal studies are now needed with comparison to standard resorbable membranes as well as long-term follow-up of implants placed into sites grafted with e-PRF membranes.