Evaluation of Periodontal Treatments Using Controlled‐Release Tetracycline Fibers: Microbiological Response

I n 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 Actinobacillus actinomycetemcomitans ( Aa ) with an average detection limit of 1.8 × 10 4 bacterial colony forming units/sample. The microbiological response to four periodontal treatments was studied, one treatment in each quadrant: scaling and root planing (S), scaling and root planing with tetracycline (TC) fiber (SF), a single application of TC fiber (F) and two serial applications of TC fiber (FF). Generally two sites were sampled in each quadrant, however, in some quadrants only one site was selected. These treatments were evaluated at baseline; immediately 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 detectable Fn ; 42.9% Pg ; 63.5% Pi ; 29.7% Ec ; 28.3% Cr ; and 5.5% Aa . No significant differences were seen in baseline proportions of these species 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 spontaneous decline in the absence of therapy over the 3‐ to 12‐month period. This response was particularly prominent with Ec , where numbers of sites with detected organisms at 1 month were approximately equal to or greater than numbers of positive sites at baseline, suggesting an opportunistic characteristic. The immediate post‐treatment levels of Pi were substantially greater than other species, suggesting the relative difficulty in eliminating this species. Detected numbers of sites with Aa 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 exceptions were observed. At 12 months, however, differences in microbiological presence related to initial therapy of each of the pathogens were small and statistically insignificant. Numerically elevated post‐therapy levels of Cr were associated with sites that lost ≥ 1 mm between the 3‐ to 12‐month post‐treatment period. However, statistically this increase was not significant. Certain differences in detectable microbial presence between treatments were noted. Sites treated by TC fiber (F, FF, SF) exhibited lower post‐therapy percentages 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 individual 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 in a lower percentage of sites with detectable levels of Fn, Pg, Pi , and Cr . J Periodontol 1995;66:700–707 .