Vascularization of an Unsuccessful Case Following Guided Bone Regeneration

This study evaluated a case which was unsuccessful after guided bone regeneration (GBR) operation with non-resorbable barrier membranes in the extraction socket of a beagle dog. To clarify the relationship between bone and vascular regeneration, a vascular resin cast model was observed under a scanning electron microscope (SEM).At 30 days post-operation, vessels from the periosteum were seen migrating to the socket through the gap between the membrane and the bone wall. The regenerated bone height was no higher than that of the pre-existing alveolar crest.At 60 days post-operation, the height of the regenerated bone was in accordance with that of the Pre-existing bone. A vascular network of granulation tissue was seen between the membrane and the upper margin of the alveolar bone. This vascular network consisted of a densely arranged vascular loop. The tracing of the circulatory pathway revealed that this network was composed of arteries from the alveolar bone marrow and veins of large diameter, which drained to the oral mucosa. The surface of a granulation tissue vessel showed a rough configuration. Resin was found to be leaking from the vascular loops.The study of this unsuccessful case clearly showed that the membrane was neither in close contact to the surrounding bone wall nor sufficiently supported by it. This resulted in an ingrowth of vessels from the periosteum to the socket. Consequently, there was no increase in bone height growth and new bone apposition did not occur. To succeed with GBR, it is essential that vascularization of the periosteum occur and that the membrane gradually cover and seal the extraction socket.