Subgingival microflora and periodontal conditions in healthy teenagers.

The composition of subgingival flora was correlated with clinical periodontal conditions in 100 teenagers aged 12 to 17 years. The Community Periodontal Index of Treatment Needs (CPITN) was used for the clinical examination. Subgingival bacterial samples were taken from the mesial surface of each first molar, two samples for dark-field microscopy and two samples for Actinobacillus actinomycetemcomitans (A.a.) cultivation. Fifty-nine subjects had at least three healthy sextants. Score 1 was the highest CPITN recording in 61 subjects and Score 2 in 30 subjects. None had scores 3 or 4. In dark-field microscopy, cocci predominated in most samples. Straight rods, fusiforms and motile rods correlated negatively to the number of healthy sextants per subject. Straight rods and fusiforms showed a positive correlation to gingival bleeding tendency at the sampled site. A.a. was isolated in four subjects. Motile microorganisms and A.a. were detected rarely in subjects with good periodontal conditions.