ERADICATION OF ACTINOBACILLUS-ACTINOMYCETEMCOMITANS FROM THE ORAL CAVITY IN ADULT PERIODONTITIS

Eradication of Actinobacillus actinomycetemcomitans from the oral cavi ty seems to be a prerequisite for successful therapeutic outcome in pa tients periodontally infected with the organism. In view of the limite d number of subgingival samples obtained in recent studies one cannot conclude, however, whether eradication has actually been achieved. In the present study clinical and microbiological parameters were monitor ed in 10 adult patients with A. actinomycetemcomitans-associated perio dontitis during successive nonsurgical and adjunctive metronidazole pl us amoxicillin (or ciprofloxacin) (AB) therapy. In every patient, 13 e xtracrevicular samples and subgingival samples from the deepest site o f every tooth present were selectively cultivated for A. actinomycetem comitans. The organism was isolated in 47 +/- 29% subgingival and 64 /- 31% extracrevicular samples. Six weeks following subgingival scalin g, A. actinomycetemcomitans was detected in 37 +/- 30% subgingival and 55 +/- 38% extracrevicular samples (n.s.). Three months after antibio tic therapy, the organism was recovered from only 1 patient. At baseli ne, 7.5 +/- 4.2% sites had a probing pocket depth (PPD) greater than o r equal to 7 mm. This proportion dropped to 2.3 +/- 2.4% after scaling (p < 0.05) and to 0.3 +/- 0.4% after AB (p < 0.05). The proportion of sites with clinical attachment loss (GAL) greater than or equal to 6 mm dropped from 23.3 +/- 13.3% to 17.7 +/- 13.4% (p < 0.05) and to 16. 8 +/- 14.6%. Statistical analysis revealed that the organism was stron gly related, at baseline, to PPD greater than or equal to 7 mm (odds r atio 9.8, p < 0.001). Six weeks after scaling, the organism was associ ated with CAL greater than or equal to 6 mm(odds ratio 1.8, p = 0.02). After scaling, high counts of A. actinomycetemcomitans in excess of 1 0(4) CFU/ml significantly interfered with attachment gain of greater t han or equal to 2mm (odds ratio 0.24, p = 0.001). Based on the present findings, eradication of A. actinomycetemcomitans seems to be possibl e with adjunctive antibiotic treatment. Elimination of the organism af ter scaling was only weakly associated with clinical improvement.