Volumetric Bone Changes After Graftless Sinus Floor Elevation Measured by CBCT: A Prospective Study

This prospective study quantified volumetric bone formation following graftless sinus floor elevation using osteotomes and immediate implant placement. Forty patients with bilateral posterior maxillary edentulism received 80 implants via the OSFE technique, and CBCT scans were acquired preoperatively, at 6 months, and at 24 months. Using semi-automated segmentation, the region of interest around each implant was reconstructed to measure total augmented volume and its distribution along the implant length. Mean augmented volume increased from baseline to 6 months by 195.4 ± 64.2 mm³ and showed minimal resorption between 6 and 24 months (−7.8 ± 15.1 mm³, p>0.05). Bone density within the augmented area, assessed in Hounsfield units, gradually shifted from values corresponding to type IV bone at 6 months to type III-like densities at 24 months. Implants with vertical bone gain ≥3 mm exhibited significantly higher insertion torque and ISQ values (p<0.01) and lower marginal bone loss. These data confirm that blood clot and membrane elevation alone can lead to stable three-dimensional bone formation around implants.