Soft tissue expansion with self-filling osmotic tissue expanders before vertical ridge augmentation: a proof of principle study.

INTRODUCTION Post-surgical graft exposition and loss of grafted bone are a common complication of vertical bone augmentation. Soft tissue expansion (STE) by implantation of osmotic self-filling tissue expanders before reconstructive surgery is an effective method for generation of soft tissue. The aim of this study was to investigate the feasibility of STE before bone augmentation with regard to clinical and histological outcomes and complications. METHODS Tissue expanders were implanted in patients requiring vertical bone augmentation. Onlay grafting was carried out after 2 months of STE. Implants were placed 4-6 months after augmentation. Vertical bone gain was analysed with cone-beam computed tomography (CBCT). Bone biopsies were investigated with micro-computed tomography (micro-CT). RESULTS Twenty-four sites in 12 patients were treated with STE. Complications of STE were perforation (two sites) and infection (two sites). At augmentation after STE, primary wound closure was easily achieved and the incidence of graft expositions was low (4%). At implant placement, high vertical bone gain of 7.5 ± 2.4 mm was found. Micro-CTs of bone revealed a good ratio of bone volume/tissue volume (mean BV/TV=0.1614 ± 0.0582). All implants were osseointegrated. CONCLUSIONS The combination of STE and subsequent vertical augmentation provided high gain of well-structured bone for further successful implant therapy and was accompanied by minimal complications.