Clinical significance of Actinobacillus actinomycetemcomitans in young individuals during orthodontic treatment. A 3-year longitudinal study.

The aim of the present study was: (1) to assess longitudinally the occurrence of Actinobacillus actinomycetemcomitans (Aa) in young subjects wearing fixed orthodontic appliances compared to matched appliance-free controls; (2) to determine whether the presence of the micro-organism at baseline could influence the periodontal status assessed 3 years later. 70 subjects, 27 male and 43 female, aged between 12 and 20 years participated in the study: 35 subjects under orthodontic treatment with fixed appliances for at least 6 months, and 35 appliance-free individuals matched for age and gender. All subjects were free of clinically demonstrable loss of attachment.