Quantitative aspects of the subgingival distribution of Actinobacillus actinomycetemcomitans in a patient with localized juvenile periodontitis.

The subgingival microflora in a patient with localized juvenile periodontitis was studied. Of the 97 sites investigated, 28 (29%) showed attachment loss. A correlation was found between the number of Actinobacillus actinomycetemcomitans cells and the clinical attachment level and probing pocket depth. Of the 97 test sites, 70 (73%) were positive for A. actinomycetemcomitans. Of the total number of A. actinomycetemcomitans cells isolated from this patient, more than 99% were found at sites with attachment loss, < 1% being present at sites without attachment loss. The mean percentage of A. actinomycetemcomitans was 21.2% at sites with attachment loss and 0.45% at sites without attachment loss. The distribution of Porphyromonas gingivalis showed a symmetrical pattern, being present at the 1st molar and 2nd premolar sites in all quadrants and at the lower incisor sites. This species was absent at multiple sites showing overt attachment loss.