Modified Osseodensification Bur (Sun Bur) for Transcrestal Sinus Floor Elevation With 2–6 mm Residual Bone Height: A Retrospective Cohort Study

OBJECTIVE: To evaluate the clinical efficacy of a modified osseodensification (OD) bur for transcrestal sinus floor elevation (tSFE) and to compare clinical outcomes between patients with residual bone height (RBH) of 2-< 4 mm (Group A) and 4-6 mm (Group B). MATERIALS AND METHODS: This retrospective study included 81 patients who underwent single implant placement with tSFE using the modified OD bur between January 2021 and January 2025. Patients were divided based on preoperative RBH into Group A (n = 33, RBH 2-< 4 mm) and Group B (n = 48, RBH 4-6 mm). Primary outcomes were bone height gain and sinus membrane perforation rate. Secondary outcomes included implant survival rate, success rate, radiographic bone coverage height, and radiographic bone coverage rate. RESULTS: With the mean observation period of 22.94 ± 15.44 months after implant placement, the overall implant survival rate was 97.53% (79/81), and the success rate was 97.53% (79/81). No significant difference in survival rate was found between groups (96.97% vs. 97.92%, p > 0.05). The overall sinus membrane perforation rate was 6.17% (5/81), with no significant intergroup difference. Bone height gain was significantly higher in Group A than in Group B (4.61 ± 1.23 mm vs. 3.11 ± 1.08 mm, p < 0.001). Group B demonstrated a significantly higher radiographic bone coverage rate (94.25% vs. 91.50%, p = 0.019) and a significantly greater mean radiographic bone coverage height (7.89 mm vs. 7.30 mm, p = 0.0031) compared to Group A. CONCLUSION: Within the limitations of this retrospective cohort, the modified OD bur for tSFE suggested surgical safety and high implant survival/success rates in patients with an initial RBH of both 2-< 4 mm and 4-6 mm. Notably, greater absolute bone gain was observed in the 2- < 4 mm RBH group, which is partly attributable to their lower baseline height. These findings suggest that both bone conditions represent viable clinical indications for this technique.