[Microbiological study in clinically characterized rapidly progressive periodontal disease].

Samples of subgingival bacteria were collected from two sites of offanteriors with greater than or equal to 6 mm deep pockets in each ten patients in a clinically characterized rapidly progressive periodontal disease. The purpose of this investigation was to study the predominant cultivable microflora at pre- and post-periodontal treatment stages, in order to monitor the clinical effects of periodontal treatment and possibly to determine the presence or absence of active disease. "Non effective site" was defined as little elimination of periodontal pocket. Some patients responded remarkably well to root curettage. However the subgingival flora of effective sites, which had been successfully treated and maintained over a period of three weeks, was still significantly different from the subgingival floras of people with healthy gingiva. The predominant cultivable microflora of diseased lesions at the pre-treatment stage, in which a similar proportion of microbiota were detected on both sites in each patient, were significantly increased proportions of Bacteroides sp., B. intermedius and B. gingivalis. Although B. gingivalis has been implicated as the etiologic agent of the disease, to which marked antibody response has been found in periodontal pockets, there were decreased proportions of B. intermedius and B. gingivalis after treatment, compared to pre-treatment stage. The results showed that non-effective lesions were associated with subgingival microflora which were populated by higher proportions of B. intermedius and E. corrodens. H. actinomycetemcomitans were detectable during the experimental periods in all sites. It was possible to indicate progressing periodontitis by examining these microflora at the pre-treatment stage. However active or progressing disease in young adults might represent not only an overgrowth of existing organisms but also an abnormality in host resistance.