Periodontal repair in dogs: effect of wound stabilization on healing

This study evaluated a biodegradable polylactic acid matrix as a wound stabilizing implant in reconstructive periodontal surgery. Supra-alveolar circumferential periodontal defects, 5 to 6 mm large, were surgically created around the mandibular premolars in 7 beagle dogs. The root surfaces in left and right jaw quadrants were treated with either heparin or saline. In this model, root surface treatment with heparin compromises periodontal repair and results in a long junctional epithelium and a reduced connective tissue repair to the root surface, whereas saline treatment results in almost complete connective tissue repair. Following heparin or saline treatment a polylactic acid implant was placed on 1 premolar in each quadrant. After 4 weeks of wound healing, the dogs were sacrificed and tissue blocks prepared for histometric analysis. Postoperatively, the implant became exposed and infected in 3 dogs and had to be removed. Therefore, the results reflect the 4 dogs in which healing progressed uneventfully. Connective tissue repair to the root surface in teeth treated with heparin averaged 82% of the defect height. Mean connective tissue repair in teeth treated with heparin and the implant was significantly greater and comprised approximately 99% of the defect height (P less than 0.05). Teeth treated with saline either with or without the implant also healed with almost complete connective tissue repair. The results support the importance of wound stabilization in periodontal wound healing. Development of biodegradable implant systems aimed at stabilizing and supporting the healing wound seems a desirable direction for future research in regenerative periodontal procedures.