Microscopic spirochete counts in untreated subjects with and without periodontal tissue destruction

The purpose of the study was to determine microscopically the %s of spirochetes at sites without periodontal destruction in subjects with destructive periodontal diseases (cases) and in subjects free of it (controls), who had not received professional prophylaxis. From a sample of 164 individuals aged between 30-44 years living in rural and urban areas of Tanzania, cases and controls were selected. Cases (n = 25) were selected who exhibited at least 3 teeth with pocket depth of > 5 mm. The controls (n = 28) had no pockets deeper than 3 mm. From each subject, 1 subgingival plaque sample was taken at the mid point of the lingual surface of 1 of the upper premolars which showed bleeding on probing but no calculus and no pockets. In addition, one subgingival sample was obtained from a pocket. Pockets contained the highest %s of spirochetes, which confirms earlier findings. A significant difference in % of spirochetes between cases and controls was found at non-destructive sites, indicating a host effect on the subgingival microflora. However, the spirochete counts at non-destructive sites did not provide a reliable measure to identify subjects with destructive periodontal disease.