Elevation of the maxillary sinus membrane for de-novo bone formation: First results of a prospective study in humans

Purpose: Sinus floor elevation via the lateral window approach represents a reliable technique for bone augmentation in the atrophic posterior maxilla. It is known that sinus membrane elevation leads to new bone formation. This prospective clinical study compared a specific technique in sinus membrane elevation with a conventional sinus floor augmentation (xenogenous/autogenous bone) in a human split mouth model. Methods: Five edentulous patients with highly atrophic posterior maxillae were included in this study. On one maxillary side a degradable PDLLA-membrane was placed to create a space underneath the sinus membrane. Contralateral a mixture of autogenous and xenogenous bone was used for sinus floor augmentation. A two-stage procedure was carried out. The following variables were assessed: bone regeneration on cone-beam computed tomography (cone-beam CT), implant success, prosthetic comfort and patient satisfaction. Bone biopsies were taken with simultaneous implant placement. The samples were histologically analyzed. Results: Cone-beam CTs revealed new bone formation on both sides. Thirty implants were placed, 15 in the augmented region and 15 in the non-augmented side. Thirty bone biopsies were taken and evaluated. Vital new bone was detected on the experimental side (osteoinductivity). On the conventional side a mixture of autogenous and residual bone substitute material was seen (osteoconductivity). Implant survival was 100% so far. Patient's satisfaction was high and prosthetic complications were not encountered. Conclusion: As it provides the highest rate of bone formation, autogenous bone in combination with bone substitute material can be considered as a very reliable standard procedure in sinus floor augmentation. The specific sinus membrane elevation technique as presented here showed satisfying results and might be a suitable alternative for maxillary sinus augmentation.