New attachment formation following periodontal surgery in a dog.

We evaluated new attachment following treatment of experimental periodontitis in a canine model. Periodontal destruction was induced over an 8-month period using silk ligatures and a soft diet, and this remained stable for 170 days before surgery. After surgical scaling and root planing of eight bicuspid teeth, the apical end of the pockets was estimated using an occlusal stent and a periodontal probe, then marked with a blade. The root surfaces of three bicuspids were treated with citric acid for 3 min, and tetracycline salt was applied to the root surfaces of two teeth. The remaining three bicuspids served as controls. Postoperatively, no attempts were made to improve oral hygiene, and on day 48 light microscopic examination of biopsy materials revealed new attachment in all treated teeth. However, in some sections new cementum and new collagen formation was much more extensive and complete in both groups of experimental teeth than in the control teeth.