Experiência de cárie dentária e bactérias cariogênicas detectadas e quantificadas pelo método da hibridização in situ fluorescente na saliva de crianças com síndrome de Down

Abstract

Down syndrome (DS) children are known to present a low dental caries prevalence. Although Streptococcus mutans and Streptococcus sobrinus are associated with dental caries in humans, their role in the etiology of dental caries in DS children is not entirely clear. Therefore this cross-sectional study aimed to assess the dental caries experience as well as the salivary counts of S. mutans, S. sobrinus and streptococci in DS children (group SD) in comparison with non-Down syndrome children (group ND). The sample included 30 DS children (aged 3-12 years) and 30 age and sex-matched ND children (aged 4-12 years). Dental examinations were performed to determine the numbers of decayed, missing and filled teeth in primary (dmf-t index) and permanent (DMF-T index) dentition according to the WHO dental caries diagnostic criteria. Unstimulated whole saliva samples were collected from all children. The fluorescence in situ hybridization (FISH) technique identified the presence and numbers of the cariogenic bacteria in saliva. The chi-square test was used to analyze the categorical variables and the Student’s t-test was used for the continuous variables. The significance level was set at 5% (p < 0.05). Children of DS group showed significantly lower dental caries experience (p < 0.001) and salivary counts of S. mutans (p < 0.001) compared to children of ND group. No significant difference was found in the salivary counts of S. sobrinus and streptococci between the two groups (p = 0.09 and p = 0.21, respectively). The salivary counts of S. mutans and S. sobrinus determined by the FISH technique were not associated with the lower caries experience observed in Down syndrome children.