BIODEGRADATION AND BIOCOMPATIBILITY OF A GUIDED TISSUE REGENERATION BARRIER MEMBRANE FORMED FROM A LIQUID POLYMER MATERIAL

Biodegradable barrier films were made by coagulating a solution of pol y(DL-lactide) in N-methyl-2-pyrrolidone on porous polyethylene pads we tted with saline solution. The semisolid films were cut into 10 x 10 m m barriers and implanted subcutaneously in rabbits. At monthly interva ls, the polymer implant sites were compared histologically to those im planted with USP negative control plastic. The polymer films were retr ieved from the surrounding tissue, dried, weighed, and the changes in molecular weight determined using gel permeation chromatography. The m olecular weight of the polymer decreased at a relatively constant rate over 5 months; however, no significant mass loss occurred until 5 mon ths postimplantation. Also, no distinct histological differences were noted between the polymer barrier and the control plastic sites until 6 months when histiocytes and multinucleated giant cells showed a mode st increase around fragmented polymer films. Similar barrier films als o were fitted over naturally occurring buccal dehiscence defects in be agle dogs and the tissue sites compared histologically at 6 months to sham-operated control sites. New bone and dense connective tissues clo sely approximated segments of the remaining polymer and demonstrated t he biocompatibility of the biodegradable films. Histomorphometric anal yses of treated sites compared to sham controls showed that the polyme r barrier is effective in promoting bone and cementum regeneration in periodontal defects in dogs. (C) 1998 John Wiley & Sons, Inc.