REPAIR FOLLOWING TREATMENT OF CIRCUMFERENTIAL PERIODONTAL DEFECTS IN DOGS WITH COLLAGEN AND EXPANDED POLYTETRAFLUOROETHYLENE BARRIER MEMBRANES

THIS STUDY WAS DESIGNED TO EVALUATE healing following treatment of per iodontal defects using 2 collagen barrier membranes with different deg rees of cross-linking, and to compare the results to those following u se of an expanded polytetrafluoroethylene (ePTFE) membrane. Horizontal , circumferential defects were created in mandibular premolar teeth of 6 beagle dogs, followed by placement of membranes and wound closure. Postoperative healing was monitored clinically for 6 months, at which time the animals were sacrificed and specimens were taken for histolog ical examination. Clinical observations indicated that the highly cros s-linked, slow-resorbing collagen membrane did not integrate with the tissues the way the less crosslinked, rapid-resorbing collagen did. Me mbrane exposure was typical for the slow-resorbing membrane in contras t to the rapid-resorbing membrane which remained covered. The inferior ity of the slow-resorbing membrane was evident by the extensive clinic al recession and the attachment level measurements taken at 6 months, and it was decided to omit this membrane from histometric analysis. Hi stological examination of root surfaces treated with rapid-resorbing c ollagen or ePTFE membranes revealed substantial reparative healing. Th e connective tissue repair amounted to 84% of the treated root surface height for the rapid-resorbing collagen and 53% for the ePTFE membran e (difference not statistically significant). However, the connective tissue repair to the rapid-resorbing collagen group root surfaces was often associated with a layer of ankylosis (44%, versus 8% of the ePTF E group). It appeared that much of the ankylotic response was initiate d from the furcation area and extended around to the buccal and lingua l surfaces. In addition, this study provided histological evidence tha t granulation tissue forming under clinically exposed and plaque conta minated ePTFE membranes can still result in connective tissue repair. It was concluded that the rapid-resorbing collagen membranes and the e PTFE membranes seem capable of stimulating periodontal connective tiss ue repair, whereas the slow-resorbing collagen membranes were unsucces sful in this effort, as seen in this dog model.