AUGMENTATION OF INTRAMEMBRANOUS BONE BEYOND THE SKELETAL ENVELOPE USING AN OCCLUSIVE TITANIUM BARRIER - AN EXPERIMENTAL-STUDY IN THE RABBIT

The aim of this investigation was to evaluate whether augmentation of intramembraneous bone beyond the skeletal envelope can be predictably achieved by placing a completely occlusive barrier on the skull bone o f rabbits, hereby creating a secluded space with bone tissue being the only adjoining tissue. The experiment was carried out in 3 New Zealan d white rabbits. In each animal, a midline incision was made down to t he bone surface of the skull and a skin-periosteal flap was raised to expose the skull bone on both sides of the midline. Two prefabricated titanium domes with an inner diameter of 4.5 mm and an inner height of 3.0 mm were installed on each side. The domes were supplied with a ho rizontal, peripheral flange and a vertical edge, fitting tightly into a circular slit, prepared by a trephine into the skull bone. This arra ngement ensured a stable anchorage of the dome and a reliable peripher al sealing of the space. The skin-periosteal flaps were relocated to c over the domes and sutured. After a healing period of 3 months, the an imals were killed and the experimental areas excised and prepared for histological transversal ground sections with each dome in situ. The r esults demonstrated complete bone fill of all domes, with no signs of ingrowth of other types of tissues, indicating that the use of a barri er with total occlusiveness, sufficient stiffness and stability and re liable peripheral sealing will result in predictable bone augmentation of spaces also beyond the skeletal envelope.