Occurrence of Actinobacillus actinomycetemcomitans and spirochetes in relation to age in localized juvenile periodontitis.

Occurrence of Actinobacillus actinomycetemcomitans (A.a.) and spirochetes was examined in relation to the age of patients suffering from localized juvenile periodontitis (LJP). Twenty LJP patients were divided into three age groups: 14-16, 17-19, and 20-25 years of age. Two sites with radiographic alveolar bone loss and two sites without bone loss were examined in each patient. Probing depth, gingival bleeding after probing, and orthopantomographic alveolar bone loss were recorded. Subgingival bacterial samples were taken from the same four sites for cultivation of A.a., and for dark-field microscopic assessment of spirochetes. A.a. was isolated in the youngest group more frequently than in the two older ones. Spirochetes were detected in the youngest group as well, but were not related to the age of the patients. A.a. occurred as frequently with as without spirochetes, both in pockets exhibiting and not exhibiting bone loss. There was no difference in the spirochete proportions between the A.a.-positive and -negative sites. The occurrence of A.a. was not related to the absence, presence, or proportions of the spirochetes, but, unlike the situation with spirochetes, was related to the age of the LJP patients. Thus the occurrence of A.a. is possibly associated with the activity of the disease.