Microbial and clinical measurements of periodontal pockets during sequential periods of non‐treatment, mechanical debridement and metronidazole therapy

Abstract

Microbial and clinical parameters were studied in 11 subjects with chronic inflammatory periodontitis. 2 periodontal pockets per subject were studied longitudinally. The microbial parameters included counts of different subgingival micro-organisms by dark field microscopy, counts of the total colony forming units (c.f.u.) on anaerobic blood agar, the facultative anaerobic counts and counts of black-pigmented Bacteroides, Fusobacterium and E. corrodens. The clinical parameters were probing pocket depth, bleeding after probing and crevicular fluid production. Clinical and microbial observations were compared during 3 consecutive periods of non-treatment, debridement and metronidazole therapy. The experimental sites were debrided by deep scaling while no debridement was carried out at the control sites. The effect of this treatment was studied over a period of 3 months. Then, at the experimental sites, a 2nd session of debridement was followed by administration of metronidazole. The effect of metronidazole alone and combined with mechanical debridement was studied during a subsequent 3-month period. The disease activity did not correlate with the microbial parameters and was evident in the presence as well as in the absence of black-pigmented Bacteroides. A single session of subgingival debridement resulted in significant reductions in probing depth, spirochetes, motile organisms, black-pigmented Bacteroides and E. corrodens. Repopulation of the subgingival sites was observed. However, the composition of the subgingival microbiota remained significantly changed during the 3 months after debridement. The re-isolation of the same Bacteroides-species and the same B. gingivalis type after treatment indicated an outgrowth of micro-organisms remaining at these sites.(ABSTRACT TRUNCATED AT 250 WORDS)