GUIDED BONE REGENERATION IN LONG-BONE AN EXPERIMENTAL-STUDY

Objective. In the concept of guided tissue regeneration (GTR), a space is created for selected cells to differentiate, proliferate and repai r the defect at last by implanting a membrane around the defect area, which serves as a physiologic barrier. This experiment was designed to test GTR in long bone, namely, guided bone regeneration (GBR). Method s, Ten New Zealand rabbits were used in this experiment. A piece of si licone membrane sutured as a tube was used to bridge a 10-mm defect on radius. IO-mm defects were also produced on the control sides. Radiog raphy of forelimbs was taken weekly until 12 weeks. Gross sample exami nation, 3-point bending test and histology were involved in evaluating bone regeneration. Results, By the 12th week, seven of 10 experimenta l sides were healed, 2 were healed with a connective cartilage zone, a nd 1 was not healed. None of the control was healed but the defect was occupied by soft tissue. Conclusions. The results of this preliminary study showed that GBR is present in long bone of rabbits. The followi ng points relate to the mechanism of GBR, providing a space for bone r egeneration; preventing surrounding tissue from the defect; increasing the density of osteogenic precursor cells and concentration of bone m orphogenetic protein (BMPs); and maintaining a complete blood clot to bridge the fracture ends in the tube, which provides a structure for o steogenic cells ingrowth.