Effects of a 5 por ciento tetracycline gel on the levels of P. gingivalis, P. intermedia and A. actinomycetemcomitans

The purpose of this investigation was to study the effects of local delivery of a tetracycline 5% gel on the levels of 3 bacteria associated to development of rapidly progressive periodontitis. In a sample of 20 patients, five teeth were selected from each patient with periodontal pockets > 5 mm and bleeding upon probing. One of the following treatments were done at each selected site: 1. Control (no treatment). 2. Local delivery of a 5% tetracycline gel. 3. Placebo gel. 4. Scaling and root planing. 5. Scaling and root planing + local application of tetracycline gel. Previously, at each selected site samples of subgingival plaque were taken with sterile paper points in order to detecte and quantify the presence of P.gingivalis, P.intermedia and A. actinomycetemcomitans, by using DNA probe technology (OMNIGENE, U.S.A.). Oral hygiene instructions were given to each patient and new samples of subgingival plaque were obtained at 60 days. Statistical analysis of results showed the following 1. No significant reductions of A. actinomycetemcomitans were found with performed treatments. 2. Scaling and root planing reduced the levels of P. gingivalis (p 0.02) or when the later was combined with tetracycline (p <0.05). 3. All treatments significantly reduced levels of P.intermedia. Although bacteria studied has shown sensitivity to tetracyclines and despite high levels of antibiotic that are obtained following its local delivery in a gel, the reduced microbiologic effects that were seen could be ascribed to rapid removal of gel by the gingival crevicular fluid from studied sites (AU)