Genotypic diversity of Streptococcus mutans associated with the risk factors for dental caries in children

Résumé

The association between the genotypic diversity of Streptococcus mutans and risk factors for dental caries in children attending an educational program in the public sector was investigated. Twenty-one children (2-7 years old) who presented at least three risk factors were allocated into two groups: caries free (n = 12); with caries activity (n = 9). Initially, 210 isolates of S. Mutans were analyzed through AP-PCR and in the second intervention (after 12 months), new evaluation of risk factors and dmf-t index was carried out, followed by statistical analysis of the data (Simple Logistic Regression and Chi-square Test). There was an association between genotype diversity and caries (p = 0.05). It was found that 66,6% of the caries-free children had one genotype, while 77.7% in the group with caries had two or more genotypes. Having two or more genotypes increased by seven times the chance of injury. Genotypic diversity was associated with inadequate eating habits and oral hygiene practices. The dmf-t index of children with two or more genotypes increased from 2.64 to 4.64. These findings suggest that harmful habits of oral hygiene and diet may favor colonization by S. mutans and greater genotypic diversity, potentializing the risk of dental caries in the children evaluated.