New bone formation in the maxillary sinus without bone grafts

Various sinus augmentation procedures, using bone substitutes, have been used to place dental implants in the atrophic posterior maxilla. The aim of this article is to evaluate the possibility of new bone formation in the maxillary sinus without a bone graft.

Ten patients without significant sinus pathosis were selected for this study. The bony window was prepared in the lateral wall using the ultrasonic piezoelectric bone surgery device (Surgybone, Silfradent srl, Sofia, Italy). The sinus membrane was elevated superiorly and implants were placed simultaneously to maintain the space under the sinus membrane for new bone formation. As the methods of sealing the lateral access window of the sinus, patients were divided into 2 groups. Nonresorbable membrane was used to seal the lateral access window of the maxillary sinus after implant placement in 5 cases (group A). Replaceable bony window was used to seal the lateral wall of the sinus in another 5 cases (group B). Computed tomograms were taken immediately before and after surgery, at the uncovering of the implant, and after a 6 month healing period. A bone biopsy was taken on the previous bony window area to evaluate new bone formation.

A total of 21 implants in lengths of 10 to 15 mm (mean, 13 mm) were placed, with an average residual bone height of 5 mm (range, 1-9 mm). All implants remained stable during the study period in clinical evaluations. New bone formation and new sinus floors were found in radiographic and histologic evaluations.

The human study showed the capacity of new bone formation in the maxillary sinus with membrane elevation only and simultaneous implant placement beyond the original sinus floor. New bone formation without additional bone graft in the maxillary sinus is revealed from the clinical, radiographic, and histologic results, but furthermore long-term studies are needed to confirm this.