Membrane Repositioning Techniques to Stabilize Graft Material in Lateral Sinus Augmentation: A Retrospective Cohort Radiographic Study

Abstract

Purpose This retrospective study compares the effects of free-lay (FL) and tucked/adapted (TK) collagen membrane placement on vertical bone height (BH) in 2D radiographs after maxillary sinus augmentation (MSA) with the lateral window approach. Materials & Methods Patients who underwent MSA between 2020 and 2025 were included in this study. In all cases, a collagen membrane was placed to cover the lateral window. Membranes were stabilized either as a free lay or by tucking the margins between the sinus wall and the graft. Panoramic radiographs were obtained preoperatively and at postoperative day 7, month 2, month 6, and the final follow-up to assess BH. Results Fifty-six patients were analyzed (FL, n = 35; TK, n = 21). BH decreased significantly over the follow-up period. Technique-by-time interactions were not statistically significant, and after adjustment, the membrane technique was not an independent predictor of bone height change. Greater mesiodistal graft width was found to be correlated with higher BH values. The staged approach was linked to higher level of BH reduction in the long term. Conclusion Within the limitations of this study, TK technique showed no measurable benefit over free-lay coverage in preserving BH after maxillary MSA. Prospective studies using CBCT-based volumetric endpoints and direct evaluation of graft displacement are recommended.