Microvascular architecture of alveolar bone after guided bone regeneration with a resorbable membrane.

Abstract

Guided bone regeneration (GBR) with the use of a resorbable membrane was performed in an experimental bone cavity to investigate the relationship between bone regeneration and vascularization, evaluated by means of vascular resin cast models and scanning electron microscopy (SEM).Two beagle dogs weighing 12 to 15kg with clinically healthy periodontal tissue were studied. The mandibular third and fourth premolars were extracted bilaterally, and the dogs were held in stock for 12 weeks to allow the sockets to heal. On one side of the mandible, a square bone cavity was then formed in the alveolar bone and covered with a resorbable membrane. As a control, a cavity was similarly created on the contralateral side but left uncovered.Twelve weeks after the operation, the regenerated bone in the bone cavity was slightly concave and the bone height was higher in the GBR group than in the control. The membrane, which showed evidence of being resorbed, was found between the superficial vascular network of the oral mucosa and the regenerated alveolar bone. Blood vessels from the periosteum increased in caliber as they passed through the resorbed part of the membrane.Our results indicate that regardless of what type of membrane is used, it only acts as a barrier preventing the oral mucosa from migrating apically to the socket, thereby creating an environment that promotes the proliferation of cells in the socket. From the viewpoint of the microcirculation, the level reached by blood vessels arising from the periosteum might play an important role in determining the final height of regenerated alveolar bone in extraction sockets.