Relationships between dietary behaviours, oral hygiene and mutans streptococci in dental plaque of a group of infants in southern England.

This report is part of a prospective study on dietary behaviours, feeding practices, oral hygiene and dental health during the first 18 months of life in a cohort of infants living in southern England. In this part of the study the prevalence of mutans streptococci in the plaque of 1-year-old children and its correlation with sociodemographic status, dietary behaviour and oral hygiene practices over the first 12 months of life were studied. Dietary habits, oral hygiene and dental health at 18 months were also studied. The study group comprised 163 infants. At 12 months of age all children had a dental examination and a plaque sample was removed from the labial surfaces of upper incisors for microbiological examination. A further dental examination took place at 18 months of age; no plaque was sampled. Longitudinal dietary information was obtained with a 3-day food diary at 6, 12 and 18 months of age. Parents/carers completed two structured questionnaires on sociodemographic factors, oral hygiene and feeding behaviour over the first 18 months of life when their children were 12- and 18-month-old. No child exhibited dental caries at 12 and 18 months of age; 18 and 25% had visible dental plaque at 12 and 18 months, respectively. Seven children (4%) had detectable mutans streptococci in their plaque at 12 months of age. Children who had started brushing their teeth or who had had their teeth brushed by 12 months of age were less likely to have detectable mutans streptococci in their plaque than those who had not (P=0.02). The amount of mutans streptococci was significantly correlated with the total number of eating/drinking events per day (P<0.001) and bordered on significant correlation with the mean daily frequency of consumption of foods and drinks containing non-milk extrinsic sugars (P=0.05). None of the sociodemographic variables-sex, social class, mother's level of education-were associated with the detection of mutans streptococci in this group of infants. Multiple logistic regression analysis revealed that two variables were independently and positively correlated with the presence of mutans streptococci in the plaque; these were age when tooth brushing started and total eating and drinking events per day.