Salivary detection of periodontopathic bacteria in periodontally healthy children

Background: Salivary occurrence of periodontopathic bacteria is of interest especially in children as a risk indicator for the transmission, development and control of periodontal disease. We assessed the prevalence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Prevotella nigrescens and Treponema denticola as microbial complexes in the saliva of children with mixed dentition and healthy gingiva. Materials and methods: Paraffin-stimulated saliva samples were collected from 41 children (22 boys and 19 girls), aged 6-13 years old. Gingival health was determined during the initial screening exam. The test bacteria were identified using a 16S rRNA-based PCR analysis. Results: P. nigrescens was the most frequent species (80%), followed by T denticola (32%), A. actinomycetemcomitans (24%) and P. gingivalis (12%). P. intemedia and T forsythia were not detected. P. nigrescens was also common species in combinations. Paired and triple bacterial combinations were found in 24% and 20% of all children, respectively. There was no positive association between bacterial combinations in colonization and subject's gender (P>0.05, Fisher exact test). Conclusion: The salivary presence of P. nigrescens, T denticola, A. actinomycetemcomitans and P. gingivalis but not P. intermedia and T forsythia can occur in childhood without clinical signs of gingival disease. Thus, the possible risk of bacterial transmissions through saliva and, the need to screen for periodontal pathogens should be considered before mixed dentition. (C) 2007 Elsevier Ltd. All rights reserved.