Healing of mandibular defects with different biodegradable and non-biodegradable membranes: an experimental study in rats.

Membranes, clinically used to improve bone regeneration according to the osteopromotion principle, have primarily been made of expanded polytetrafluoroethylene (Gore-Tex Membrane). Recently, different types of biodegradable membranes have become available. This investigation explored the osteopromotive potential of 10 different biodegradable and non-biodegradable membrane materials. Scanning electron microscopy revealed quite different surface configurations of these membranes, even though some of them were chemically closely related. Standardized, transosseous, critical size mandibular defects were made bilaterally in adult rats and were randomly covered with the different types of membrane. After 6 wk of healing, evaluation was performed by light microscopy according to a histological scoring system. Varying degrees of bone healing were seen beneath the different membranes. Some of the membranes (such as Gore-Tex Augmentation Material, Millipore and Resolut 'long term') revealed a good osteopromotive effect, whereas others had little or no beneficial effects on bone healing. Certain membrane materials caused a pronounced inflammatory response in the surrounding soft tissue, while others displayed a low inflammatory reaction. The study shows that different membranes differ strongly in osteopromotive efficacy, even if seemingly chemically closely related. Furthermore, the study demonstrates that membranes developed primarily for periodontal regeneration purposes may not be adequate to promote bone healing.