Less Invasive Window Repositioning Technique for Sinus Floor Elevation: A Clinical and Radiographic Study

Purpose: To determine whether a less invasive window repositioning technique could provide a feasible, safe, and reliable lateral sinus augmentation.
Materials and methods: The less-invasive window repositioning technique using a piezoelectric saw was performed on adult patient candidates for lateral sinus floor elevation. The augmented bone height (primary outcome variable), bone length, and posthealing outcome variables were evaluated to determine the augmentation adequacy, safety, and reliability of this technique overall and in one- and two-implant groups with different window dimensions. Data were analyzed using descriptive statistics, chi-square test, and Pearson correlation analysis. P < .05 was considered significant.
Results: A total of 50 consecutive sinus floor elevations with simultaneous placement of 66 implants (one-implant: 34, two-implant: 16) were performed on 44 subjects (72% men) with a mean age of 46.7 ± 10.3 years and followed for a mean of 13.28 ± 3.5 months. The overall, one-implant, and two-implant group mean window sizes were 31.38 ± 6.78 mm2, 28.38 ± 4.2 mm2, and 37.75 ± 6.88 mm2, respectively. The mean overall augmented bone height and length were 12.3 ± 1.04 mm and 19.67 ± 2.01 mm, respectively. The mean window size was significantly smaller in the one-implant group versus the two-implant group (P < .001). However, there was no correlation between window size and augmented bone height (r = -0.9, P = .54) and length (r = 0.05, P = .68). The posthealing outcome variables showed perfect window integration without soft tissue ingrowth. Six sinus perforations (12%) during membrane elevation that were not related to window osteotomy were observed and were appropriately managed.
Conclusion: The less-invasive window repositioning technique is feasible, safe, and reliable for appropriate sinus augmentation in height and length. The reduction of window dimension does not influence the feasibility, augmentation adequacy, and surgical safety and does not increase surgical risks or membrane perforation. The repositioned window showed proper integration. Also, sinus floor elevation through this technique is an experience-based surgery that requires delicate instruments.