Early tissue reactions to polylactic acid resorbable membranes: a histological and histochemical study in rabbit.

The aim of this study, in rabbit tibia, was an evaluation of the early reactions of the tissues to the insertion of polylactic membranes, used in connection with titanium implants. The specimens were retrieved after 1-4 weeks, and a histological analysis was performed. It was possible to see that, in the early implantation phases, no degradation of the macrostructure of the membrane was present. On the outer portion of the membrane many multinucleated giant cells (MGC) were present and membrane fragments were present inside the cytoplasm of these cells. These cells could explain the inflammatory processes reported, in some reports, with the use of materials made by polylactic and polyglycolic acid. We did not observe detrimental effects in the bone tissue around the membrane, and the membrane appeared to have a mechanical stability for the time necessary for bone regeneration.