QUANTITATIVE ANALYSIS OF AGGREGATIBACTER ACTINOMYCETEMCOMITANS IN DENTAL PLAQUE SAMPLES OF MOROCCAN SCHOOL CHILDREN WITH AND WITHOUT PERIODONTITIS

Abstract

Objectives: Microbial infection and the host response to the infection play a significant role in the etiology of periodontal diseases. Previous studies reported a relatively high prevalence of periodontitis among adolescents in Morocco. The importance of the composition of subgingival plaque and the presence and proportion of Aggregatibacter actinomycetemcomitans to the total plaque bacteria in the pathogenesis of periodontitis is not well understood. The purpose of this study is to compare the relative abundance of A. actinomycetemcomitans in subgingival dental plaque from young Moroccans with aggressive periodontitis, chronic periodontitis, and those without periodontitis, and to construct a multivariable model to investigate the effect of demographic attributes of age, gender and relative ratio of A. actinomycetemcomitans in dental plaque with periodontal disease status. Methods: Sample population includes 984 subjects, aging from 12-20 years old, who were surveyed and examined for periodontal disease status. 82 subjects were selected consisting of 26% aggressive periodontitis, 12% chronic periodontitis, and 62% without periodontitis. Subgingival plaque was collected from these 82 subjects. Whole DNA was extracted and purified, and real-time PCR was used employing a primer for eubacteria, and specific primer for A. actinomycetemcomitans. PCR assays confirmed the amplification and quantification of DNA of total bacterial and A. actinomycetemcomitans. Results: 73% of the subjects harbored A. actinomycetemcomitans: 63% in aggressive periodontitis, 90% in chronic periodontitis, and 73% in controls. The percentage A. actinomycetemcomitans to total bacterial load increased with age, was similar among males and females, and was somewhat higher in persons with periodontitis than the controls. Using a logistic regression analysis that included age, gender and A. actinomycetemcomitans ratio showed that only age is significantly correlated with the diagnosis of periodontitis in this population. Conclusions: A. actinomycetemcomitans is prevalent among this young Moroccan group and is somewhat more prevalent in subjects with periodontitis than the controls. However, the presence and ratio of this species to the total bacteria in subgingival plaque explained only a small proportion of the variance in periodontitis in this group.