FACTORS ASSOCIATED WITH DIFFERENT RESPONSES TO PERIODONTAL THERAPY

In a study of the efficacy of modified Widman flap surgery and scaling and root planing accompanied by I of 4 systemic adjunctive agents, Augmentin, tetracyline, ibuprofen or placebo, it was observed that subjects differed in their response to therapy. The difference was only partially accounted for by the adjunctive agent employed. The purpose of the present investigation was to examine clinical and microbiological features in subjects who showed different levels of attachment change post-therapy. 40 subjects were subset into 3 groups based on mean attachment level change post-therapy. 10 poor response subjects showed mean attachment loss; 19 moderate response subjects showed mean attachment gain between 0.02-0.5 mm and 1I good response subjects showed a mean gain of attachment >0.5 mm. Clinical parameters were measured at 6 sites per tooth both pre- and post-therapy. Microbiological samples were taken from the mesial aspect of each tooth and evaluated individually for their content of 14 subgingival taxa using a colony lift method and DNA probes. % of sites colonized by each species was computed for each subject both pre- and post-therapy. Significant differences were observed among treatment response groups for mean probing pocket depth, attachment level and % of sites with plaque pre-therapy. The poor response subjects had the lowest mean probing pocket depth and attachment level, but the highest plaque levels. Post-therapy, the poor response group exhibited the greatest degree of gingival inflammation as assessed by gingival redness and bleeding on probing. Subjects in the good response group showed decreases in the % of sites colonized for 9 of 14 test species, while subjects in the poor response group showed an increase in % of sites colonized for 12 species. The differences in change in % of sites colonized among groups were significant for B. forsythus and P. gingivalis. The majority of attachment loss in poor response subjects occurred at sites with pre-therapy probing pocket depths <4 mm. Subjects with moderate or good treatment responses had fewer shallow or moderate sites showing attachment loss and a large proportion of sites in all probing pocket depth categories showing attachment gain. Sites that lost attachment greater than or equal to 2 mm post-therapy showed a significant increase in counts of P. intermediate, B, forsythus and A. actinomycetemcomitans b, while sites that gained attachment showed a decrease in these species. The data indicated that subjects who showed a good treatment response exhibited a decrease in the level of gingival inflammation and a marked reduction in the % of sites colonized by suspected periodontal pathogens. In subjects showing a poor treatment response, the level of gingival inflammation was not decreased and levels of periodontal pathogens increased.