Suppression of subgingival Actinobacillus actinomycetemcomitans in localized juvenile periodontitis by systemic tetracycline

Abstract The current study assessed the clinical and microbiological effects of systemic antimicrobial therapy alone in Actinobacillus actinomycetemcomitans‐infected adolescents with periodontal disease. The study involved 6 localized juvenile periodontitis patients 13–18 years of age, who harbored high numbers of A. actinomycetemcomitans: in subgingival plaque samples. The periodontal lesions were microbiologically monitored by selective culture, and clinically assessed for probing pocket depth and periodontal attachment level 3 months prior to baseline, and at 3, 6, 12, and 24 months posttreatment. Tetracycline‐HCl (250 mg/ QID) was prescribed until 1 week after subgingival A. actinomycetemcomitans was no longer detectable or for a maximum of 8 weeks. During 3 months prior to treatment, pocket depth was unchanged, and was then significantly reduced from an average of 7.1 mm to 5.1 mm 12 months after treatment (p ‐ 0.02). The mean change in clinical attachment level was a gain of 1.4 mm between baseline and 12 months (p= 0.02). 3 of the 6 patients were still infected with A. actinomycetemcomitans after 8 weeks of antibiotic therapy and 4 subjects were infected at 12 months. Numbers of A. actinomycetemcomitans were still suppressed in most lesions. There was a strong association between mean numbers of A. actinomycetemcomitans in periodontal pockets and mean change in probing attachment level at any given time point. For 22 available comparisons, derived from all time points, there was a strong association (r= 0.68) between subgingival A. actinomycetemcomitans and change in probing attachment level. 8 of 9 (89%; sensitivity) individual patient time intervals with “disease” (< 1.5 mm gain in probing attachment level) were tested positive (≥ 100 CFUJ, whereas 9 of 13 (69%; specificity) individual patient time intervals with “no disease” (≥ 1.5 mm gain in probing attachment level) were A. actinomycetemcomitans negative (< 100 CPU) (p= 0.007).