Detection rate of Actinobacillus actinomycetemcomitans on the permanent 1st molars of primary school children in Taiwan by polymerase chain reaction

Background, aims: Actinobacillus actinomycetemcomitans (Aa) has been implicated as the putative micro-organism for localized juvenile periodontitis (LJP). The most distinct clinical features of LJP include severe angular bony defects of the mesial sides of permanent first molars and the onset of disease during puberty. Currently, no large-scale studies have been performed which address the change in detection rates of Aa on the mesial sides of permanent 1st molars following eruption and up to puberty. Method: In this study, subgingival plaque samples were taken from the mesial pockets of 2 randomly selected permanent 1st molars from 328 primary school children and 50 adult staff, and analyzed by polymerase chain reaction (PCR) to detect Aa. Results: The results showed a 5.5% prevalence rate of Aa which increased after the eruption of 1st molars and peaked near puberty. There were no significant differences in the detection rates of Aa among different groups in terms of gender, plaque index (PlI), and gingival index (GI); however, the higher detection rates of Aa were significantly associated with increased probing depths at p<0.05. Conclusion: PCR analysis of the subgingival plaques demonstrated a prevalence of Aa which peaked near puberty, suggesting that Aa may be important for LJP in Taiwan.