HEALING OF BONE DEFECTS BY GUIDED TISSUE REGENERATION

Abstract

Guided bone formation is the controlled stimulation of new bone formation in a bony defect• either by osteogenesis, osteoinduction or osteoconduction reestablishing both structural and functional characteristics. It is based on the hypothesis that different cellular components in the tissues have varying rates of migration into a wound area during healing. Therefore, by a mechanical hindrance using a membrane technique, fibroblasts and other soft connective tissue cells are prevented from entering the defect, allowing the presumable slower cells with osteogenic potential to repopulate the defect. The aim of this study was to: 1- Investigate the additive effect of osteoconductive and osteoinductive materials to guide bone regeneration principle. 2- Investigate the possibility of ustng customized membranes to regenerate bony defects in the shape and volume necessary to achieve the best aesthetic and functional results. To investigate the first aim, critical size defect model in skull of rats were used. For osteoconduction, the osteoconductive implants maintain the space under the membranes, while the membranes prevent fibrous integration. For osteoinduction, there should be good concentrations of the osteoinductive substances (bone morphogenetic proteins) and access to inducible mesenchymal cells. Therefore, the best way was to load the bone morphogenetic proteins to the resorbable membranes used for guided bone regeneration. If the defect underneath the membranes was maintained, the membrane technique alone allow slow but predictable bone formation.