The effect of local doxycycline with and without tricalcium phosphate on the regenerative healing potential of periodontal osseous defects in dogs.

The purpose of this study was to evaluate the clinical and histological effects of high concentration doxycycline on osseous regeneration in adult beagle dogs. Four 5 mm two-wall periodontal osseous defects were created in the premolar and molar area of each quadrant yielding a total of 48 defects in the three dogs. Ligature-induced periodontitis was maintained for 6 weeks. Two weeks following ligature removal, one of the following graft procedures was randomly assigned to each defect: 1) doxycycline alone (DOX); 2) tricalcium phosphate alone (TCP); 3) a combined graft of DOX plus TCP, or 4), surgically debrided control. All areas received thorough scaling and root planing at the time of surgery. Clinical parameters evaluated at 4, 12, and 20 weeks after the surgical treatment included the gingival index and probing depths. Crevicular fluid was examined at 3, 10, and 28 days postoperatively for tetracycline fluorescence. Direct clinical measurements from the CEJ to a notch placed at the base of the defect and from the CEJ to the alveolar crest were made at the time of surgical treatment and reentry. The reentry procedures were performed at 4, 12, and 20 weeks postoperatively. Immediately following reentry block sections were obtained from each quadrant and prepared for examination with the light microscope. The gingival index and probing depth measurements showed greater improvement in the DOX and DOX + TCP groups. Increased regeneration (new bone, cementum, and periodontal ligament) and reduced alveolar crest resorption were observed more frequently in DOX and DOX + TCP defects, while healing by long junctional epithelium was more common in defects not treated with doxycycline.(ABSTRACT TRUNCATED AT 250 WORDS)