Maxillary Sinus Augmentation using TGF-β and Bone Grafting in Dogs

Dental implants may maintain residual alveolar ridge, avoid preparation of the healthy tooth, and provide better retention, support, and chewing functions. However, in the maxillary posterior areas the size and extension of the sinus cavities often jeopardized implantation of dental implants. The mechanisms involved in sinus augmentation and osseointegration are still not fully understood. The amount of new bone regenerated may not be adequate and the time for bone healing may take years to complete; therefore, the success rate of osseointegration in augmented sinus may be lower. Two critical processes for the enhancement of bone healing are to increase the number of local osteoprogenitor cells and to accelerate the rate of bone remodeling. TGF-β may directly or indirectly regulate cells of the bone marrow and re-establish the osteoblast phenotype and enhance new bone formation. During skeletal remodeling, bone grafting materials may also be used to induce or conduct new bone formation. The purpose of this investigation was to evaluate the potential use of TGF-β and / or bone grafting materials on sinus augmentation in vivo. Two, four and six months after sinus elevation and TGF-β and bone graft implantation, dogs were sacrificed. Results were assessed using clinical, histologic, and radiograghic techniques. SEM examination was also performed to evaluate the level of osseointegration ultrastructurally. Computed tomography (CT) showed an increase in mineralization over time for all study groups. CT showed that sinuses grafted with TGE-β /OsteoGen or autogenous bone/OsteoGen exhibited greater bone density than sites grafted with OsteoGen only. Histological results of the present study indicated that TGF-β/OsteoGen, autogenous bone/OsteoGen, and OsteoGen promoted similar amount of new blood vessels and new bone in grafted maxillary sinus. It appeared that TGF-β/OsteoGen formed more new bone marrow. New bone was formed primarily around OsteoGen. While OsteoGen was resorbed, there were still tremendous amounts of residual OsteoGen particles after 6 months of grafting. More new bone marrows were formed as graft time increased.