A 2-year follow-up on the clinical and microbiological conditions of periodontium in teenagers

87 teenagers were included in a 2‐year follow‐up study on clinical and microbiological conditions of the periodontium. The clinical status was determined according to the Community Periodontal Index of Treatment Needs (CPITN) for subjects under 20 years of age. 59% of the subjects had at least 3 healthy sextants at the baseline and 68% at the 2‐year examination. The microbiological conditions were assessed by using direct dark‐field microscopy, and the culture of Actinobacillus actinomycetemcomitans (A.a.). Subgingival bacterial samples were taken, 2 for the microscopy and 2 for the culture, from the mesial surfaces of the first molars of each subject. The presence of gingival bleeding after probing was separately recorded from the 2 sites sampled for dark‐field microscopy. No gingival bleeding at these 2 sites was found at the 2‐year examination in 55% of those subjects who were non‐bleeding at baseline, in 46% of the subjects initially with 1 bleeding site and in 13% of the subjects with both sites bleeding at baseline. 55% of the subjects with neither fusiforms, motile rods nor spirochetes at baseline maintained their healthy flora for 2 years. A.a. was recovered in 4 subjects at baseline and in 5 subjects 2 years later, in 3 of them at both examinations. Longer follow‐up periods are needed to reveal the significance of the constant recovery of A.a. from the same subjects.