Association between Streptococcus Mutans and S. Sanguinis in Childhood Caries

Background: Early childhood caries is one of the most common diseases worldwide. S. mutans is strongly associated with caries. Previous studies have reported the antagonistic relationship between S. sanguinis and S. mutans and suggest that S. sanguinis might delay the colonization of S. mutans in oral cavities . This study was aimed to quantify S. mutans in plaque and S. sanguinis in saliva between 2 groups and to analyze the association between these bacteria and caries-related factors.

Methods: Supra gingival plaque was obtained from 120 Thai children aged 2-5 yr (S-ECC=CF=60). After overnight plaque samples were collected, saliva was expectorated into a cup. Recorded plaque and gingival indices and dmft scores. Assessed parent’s demographic and child’s oral hygiene care and diet using questionnaire. After DNA extraction, quantitative real-time PCR was performed.

Results: Guardian’s education and occupation, relationship to the child, family income, duration of bottle feeding, sleeping with bottle, brushing’s frequency, drinking water after milk feeding and regular dental treatment, frequent consumption of sugar coated snack, soft drink, candies, potato chip and Thai dessert were different between 2 groups. S. mutans in plaque, ratio of S. mutans to total bacteria in plaque were higher in S-ECC. S. sanguinis in saliva, total bacteria, ratio of S. sanguinis to S. mutans and ratio of S. sanguinis to total bacteria were higher in caries-free group. Plaque and gingival indices in S-ECC were higher than caries-free. S. mutans level in plaque was correlated with dmft score, age, and gingiva index. Salivary S. sanguinis was inversely correlated with dmft score and gingiva index but positively correlated with plaque index.

Conclusion: S. mutans was associated with caries and other factors while S. sanguinis in saliva was associated with caries-free. Socioeconomic, and child’s oral hygiene care and diet were associated with S-ECC.