[Osteotome sinus floor elevation without bone grafting: a 2-year prospective clinical study].

Purpose: The aim of this study was to evaluate the osteotome sinus floor elevation procedure with Straumann implants without bone grafting through observing the implant survival rate and the change of bone around the implant, and explored new bone formation and stability when the implants protruding in the sinus less than 3mm.

Methods: 23 patients with single upper maxillary molar lost were included in this study. The mean residual bone height (RBH) under the maxillary sinus was 5-8 mm and the distance of the implants protruding into the sinus was less than 3mm without bone grafting. A healing period of 3-4 months was allowed before abutment tightening at 35 N x cm. All the patients were followed up for 2 years to evaluate the implant survival rate. X-ray measurements (immediately after implant placement, after 3,6,12,24 months postoperatively) were performed to calculate the length of the implant protruding into the sinus and if the new bone formed near it.

Results: At the end of 2-year, the implant survival rate was 100% and the implants resisted the applied 35 N.cm torque and supported the definitive prosthesis well. The mesial and the distal sides of the implants protruding into the sinus had new bone formation. No hard tissue could be seen around the apical implant 3 months after inserting and the boundary between the new bone and the original sinus floor could not be seen 2 years after surgery.

Conclusion: Elevation of the sinus membrane alone without addition of bone grafting could have the similar effect to the OSFE with bone grafting.