Collagen membranes prevent apical migration of epithelium and support new connective tissue attachment during periodontal wound healing in dogs

The capacity of collagen membranes to prevent the apical migration of epithelium and to support new connective tissue attachment was assessed in experimental perodontal defects in dogs. Experimental periodontal defects were produced in 8 mongrel dogs by removing the alveolar bone and the periodontal ligament over the most coronal 5 mm of the labial aspect of the maxillary canines. Experimental defects associated with the right canine and its surrounding bone were covered by collagen membranes prepared by air drying gels of rat type I fibrillar collagen. Flaps were repositioned and sutured. The contralateral control defects were sham‐operated without using collagen membranes. Animals were killed, 10 and 30 days after surgery, 4 at each time point. The experimental and control sites were processed for histologic and histomorphometric evaluation. At 10 d, the average distance between the apical margin of the epithelium and the apical level of the defect (EA) sites was 3.20±0.55 mm for the experimental sites and 0.73±0.18 mm for the controls. The experimental root surfaces apical to the epithelium and the collagen membranes were covered by connective tissue cells. At 30 d, the EA for experimental and control sites were 2.55±0.36 mm and 0.47±0.30 mm, respectively. In the experimental sites healing by long junctional epithelium was observed in the coronal 40% of apicoocclusal dimension of the defect and new connective tissue attachment with inserting fibers in the apical 55% of the defect length. No new bone formation was observed. In the control sites, pocket formation was found in the most coronal one‐third of the defect. Healing by long junctional epithelium was found in the most apical two‐thirds of the defect. Collagen membrane remnants were not identified at 30 d. These results indicate that collagen membranes have the capacity to partially prevent epithelial apical migration and to support new connective tissue attachment formation in experimental periodontal defects in the dog.