Histological evaluation of healing and revascularization of the subepithelial connective tissue graft

The goal of this investigation was to histologically evaluate the healing and revascularization of the subepithelial connective tissue graft in dogs.

Six beagle dogs were used in this study. Recession defects were surgically created on maxillary left P2 and right P2, and maxillary and mandibular left central and lateral incisors. The defects were left untreated for 35 days. After elevating a split thickness flap, the graft was harvested from the palate and placed over the denuded root surfaces. The flap was then coronally repositioned and sutured. Three dogs provided the specimens for 7- and 14-day time points and 3 dogs for 28- and 60-day time points. The animals were sacrificed and the blocks obtained were divided in half. One half was processed following the Spalteholtz method and the other was processed for routine histologic examination.

At 7 days, a clot was present at the demarcation zones and it was more organized at 14 days. At 28 days, the junctional epithelium was formed and the demarcation zones could not be delineated. At 60 days, the oral epithelium had regained its normal appearance. The attachment of the graft to the root surface was mediated by a combination of epithelial downgrowth and connective tissue attachment. Minimal new bone and cementum formation was observed. The vascularization of the graft at 7 days originated from the periodontal plexus and the overlying flap. At 14 days, the graft was completely vascularized. At 28 and 60 days, normal vascularization was present.

The vascularization of the connective tissue graft originates from the periodontal plexus, the supraperiosteal plexus, and the overlying flap. The attachment of the graft to the root surface appears to be mediated by a combination of epithelial downgrowth and connective tissue attachment. There is little potential for new cementum and new bone formation.