EVALUATION OF PERIODONTAL TREATMENTS USING CONTROLLED-RELEASE TETRACYCLINE FIBERS - MICROBIOLOGICAL RESPONSE

IN A 12-MONTH MULTI-CENTER STUDY OF 116 adult periodontitis subjects, six putative periodontal pathogens were monitored by DNA probe methods in a subset of 31 subjects. Monitored species included Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium nucleatum ( Fn), Eikenella corrodens (Ec), Campylobacter rectus (Cr), and Actinoba cillus actinomycetemcomitans (A alpha) with an average detection limit of 1.8 x 10(4) bacterial colony forming units/sample, The microbiolog ical response to four periodontal treatments was studied, one treatmen t in each quadrant: scaling and root planing (S), scaling and root pla ning with tetracycline (TC) fiber (SF), a single application of TC fib er (F) and two serial applications of TC fiber (FF). Generally two sit es were sampled in each quadrant, however, in some quadrants only one site was selected. These treatments were evaluated at baseline; immedi ately following therapy; and post-treatment at 1, 3, 6, and 12 months. The study was conducted with a split-mouth design with no maintenance therapy over a 12-month period. At baseline, 70.8% of sites had detec table Fn; 42.9% Pg; 63.5% Pi; 29.7% Ec; 28.3% Cr; and 5.5% A alpha. No significant differences were seen in baseline proportions of these sp ecies between centers. Numbers and proportions of detectable pathogens (with the exception of Pg) exhibited a triphasic temporal response: a precipitous initial decrease immediately following therapy; a rise in proportions in the 1- to 3-month post-therapy period; and a spontaneo us decline in the absence of therapy over the 3- to 12-month period, T his response was particularly prominent with Ec, where numbers of site s with detected organisms at 1 month were approximately equal to or gr eater than numbers of positive sites at baseline, suggesting an opport unistic characteristic. The immediate post-treatment levels of Pi were substantially greater than other species, suggesting the relative dif ficulty in eliminating this species. Detected numbers of sites with A alpha were too low to provide data for meaningful analysis, In general all treatments reduced the numbers of sites positive for each of the species tested throughout the 1-year monitoring period, although excep tions were observed. At 12 months, however, differences in microbiolog ical presence related to initial therapy of each of the pathogens were small and statistically insignificant, Numerically elevated post-ther apy levels of Cr were associated with sites that lost greater than or equal to 1 mm between the 3- to 12-month post-treatment period, Howeve r, statistically this increase was not significant. Certain difference s in detectable microbial presence between treatments were noted. Site s treated by TC fiber (F, FF,SF) exhibited lower post-therapy percenta ges of detectable Fn, Pg, Pi, and Cr in 56 out of 60 comparisons with scaling and root planing (S) over the monitoring period. Though each i ndividual comparison was not generally statistically significant, the probability of this repeated observation occurring by chance alone is extremely low. Similarly, when compared with scaling and root planing (S) alone, the adjunctive use of TC fiber (SF) consistently resulted i n a lower percentage of sites with detectable levels of Fn, Pg, Pi, an d Cr.