Implant survival following sinus membrane elevation without grafting and immediate implant installation with a one-stage technique: an up-to-40-month evaluation.

Abstract

Various augmentation procedures involving the maxillary sinus, using bone substitutes or bone, have been used to enhance bone support for dental implants. The aim of this study was to retrospectively evaluate the status of implants in patients who had undergone a maxillary sinus lift and immediate implant placement without the addition of graft material. Nineteen patients who had required bone augmentation of their maxillary sinus floor were evaluated in this study. After a bone window in the lateral wall of the sinus has been prepared and the Schneiderian membrane had been carefully elevated, dental implants were inserted in the residual bone, creating a membrane elevation. Resorbable collagenous membrane was used to seal the lateral access window of the maxillary sinus after implant placement. Clinical and radiological follow-up was carried out up to 40months after implant installation. A total of 28 implants in lengths of 10 and 12mm were placed in a one-stage healing protocol, with an average residual bone height of 5.25mm (SD=1.48). All implants remained stable, with a survival rate of 100%. An increase in mean bone height of 4.75mm (SD=1.13) was gained. The marginal bone levels relative to the coronal aspect of the implant shoulder exhibited a mean change of 1.01mm (SD=0.49) from the baseline. Of the 19 patients, none showed a plaque index or gingival index greater than 2, and 14 patients showed no presence of plaque. The findings of the study regarding the immediate placement of implants without the use of bone grafts or other bone substitute materials demonstrate a successful approach for new bone formation around implants in the posterior part of the maxilla, when the preoperative height of the subantral bone is moderate and enough to achieve primary stability.