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 periodontal defects using 2 collagen barrier membranes with different degrees of cross-linking, and to compare the results to those following use 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 histological examination. Clinical observations indicated that the highly cross-linked, slow-resorbing collagen membrane did not integrate with the tissues the way the less crosslinked, rapid-resorbing collagen did. Membrane exposure was typical for the slow-resorbing membrane in contrast to the rapid-resorbing membrane which remained covered. The inferiority of the slow-resorbing membrane was evident by the extensive clinical recession and the attachment level measurements taken at 6 months, and it was decided to omit this membrane from histometric analysis. Histological examination of root surfaces treated with rapid-resorbing collagen or ePTFE membranes revealed substantial reparative healing. The connective tissue repair amounted to 84% of the treated root surface height for the rapid-resorbing collagen and 53% for the ePTFE membrane (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 ePTFE group). It appeared that much of the ankylotic response was initiated from the furcation area and extended around to the buccal and lingual surfaces. In addition, this study provided histological evidence that granulation tissue forming under clinically exposed and plaque contaminated ePTFE membranes can still result in connective tissue repair. It was concluded that the rapid-resorbing collagen membranes and the ePTFE membranes seem capable of stimulating periodontal connective tissue repair, whereas the slow-resorbing collagen membranes were unsuccessful in this effort, as seen in this dog model.