A prospective randomized controlled trial of the two-window technique without membrane versus the solo-window technique with membrane over the osteotomy window for maxillary sinus augmentation.

BACKGROUND: Maturation of the grafted volume after lateral sinus elevation is crucial for the long-term survival of dental implants.

PURPOSE: To compare endo-sinus histomorphometric bone formation between the solo- and two-window maxillary sinus augmentation techniques with or without membrane coverage for the rehabilitation of multiple missing posterior teeth.

MATERIALS AND METHODS: Patients with severely atrophic posterior maxillae were randomized to receive lateral sinus floor elevation via the solo-window technique with membrane coverage (Control Group) or the two-window technique without coverage (Test Group). Six months after surgery, bone core specimens harvested from the lateral aspect were histomorphometrically analyzed.

RESULTS: Ten patients in each group underwent 21 maxillary sinus augmentations. Histomorphometric analysis revealed mean newly formed bone values of 26.08 ± 16.23% and 27.14 ± 18.11%, mean connective tissue values of 59.34 ± 12.42% and 50.03 ± 17.13%, and mean residual graft material values of 14.6 ± 14.56% and 22.78 ± 10.83% in the Test and Control Groups, respectively, with no significant differences.

CONCLUSIONS: The two-window technique obtained comparative maturation of the grafted volume even without membrane coverage, and is a viable alternative for the rehabilitation of severely atrophic posterior maxillae with multiple missing posterior teeth.