RESPONSE TO PERIODONTAL THERAPY IN PATIENTS WITH HIGH OR LOW-LEVELS OF P-GINGIVALIS, P-INTERMEDIA, P-NIGRESCENS AND B-FORSYTHUS

In a previous study, subjects receiving either adjunctive tetracycline or Augmentin showed, on average, more attachment level gain 10 months posttherapy than subjects receiving either Ibuprofen or a placebo, al though some subjects in each treatment group showed loss of attachment post-therapy. Since differences in treatment response might have been due to differences in the subgingival microbiota, the response to dif ferent therapies in subjects with different pre-therapy subgingival mi crobiotas was evaluated. 29 subjects exhibiting loss of attachment >2. 5 mm at 1 or more sites during longitudinal monitoring were treated by modified Widman flap surgery at deep sites, subgingival scaling at al l other sites and were randomly assigned one of the following agents: Augmentin, tetracycline, ibuprofen or a placebo. Treatment was complet ed within 30 days, during which time the subject took the assigned age nt. Subgingival plaque samples were taken from the mesial surface of e ach tooth at each visit and evaluated for their content of 14 subgingi val species including P. gingivalis, P. nigrescens, P. intermedia and B. forsythus using DNA probes. 18 subjects with mean counts >10(5) of 2 or more of these 4 species comprised the high test species group; 11 subjects with mean counts >10(5) of 0 or 1 of the species, the low te st species group. Because this was a post-hoc analysis, the number of subjects in some of the treatment/test species groups was small. Howev er, the 8 high test species subjects who received tetracycline showed the most attachment level gain (0.83+/-0.20 mm), while the 3 tetracycl ine-treated, low test species subjects showed minimal gain (0.05+/-0.2 8 mm) 10 months post-therapy. Low test species subjects receiving Augm entin (n=2) showed a mean gain in attachment of 0.67 (+/-0.59) mm. The mean % of sites showing either attachment gain or loss greater than o r equal to 2 mm was computed for each treatment/test species group. Hi gh test species subjects receiving tetracycline exhibited the best rat io of gaining to losing sites (16.2), followed by low test species sub jects receiving Augmentin (14.1). Periodontal pockets <7 mm pre-therap y in low test species subjects treated with Augmentin and high test sp ecies subjects treated with tetracycline showed attachment gain more f requently than attachment loss. The greatest proportion of gaining sit es was seen at pockets >6 mm, particularly in subjects receiving adjun ctive tetracycline. Overall, the data indicated that a gain in mean at tachment level post-therapy was significantly associated (p<0.001) wit h an increase in C. ochracea accompanied by a decrease in B. forsythus , P. gingivalis, P. intermedia and P. nigrescens. The 4 test species w ere decreased more in subjects receiving tetracycline. In contrast, Au gmentin appeared to be effective in decreasing the % sites colonized b y A. actinomycetemcomitans and in increasing the proportion of sites c olonized by C. ochracea. Knowledge of the baseline microbiota should i mprove the choice of an appropriate adjunctive antibiotic for periodon tal therapy.