Early childhood caries (ECC) remains a serious problem in several developing and developed countries. This cluster randomised trial evaluated the impact of a 6-month educational intervention on ECC. The trial targeted 12- to 15-month-old children (n = 242) and their mothers in Tehran, Iran, visiting 18 public health centres, randomly selected and assigned to two intervention groups and one control group. At baseline, each mother was interviewed and each child underwent a dental examination of all teeth for the number of decayed teeth (dt) and of upper central incisors for the number of teeth with enamel caries (de). All mothers in the two intervention groups (A and B) received oral health instructions from the vaccination staff. In addition, group A received extra reminders. The outcome was defined as increments in the number of teeth with dt or de, as percentages of children developing new dt or de, and as the number needed to treat (NNT). No new de appeared in group A, the mean de increment in group B was 0.2 (SD = 0.6), and in the controls, it was 0.4 (SD = 0.7) (p < 0.05). The percentages of children developing new de were 0, 14, and 26%, respectively. No differences in dt increments were found. Regarding de, NNT for group A was 4 and for B 9; the figures for dt were 13 and 17, respectively. In conclusion, oral health education given to mothers by general health staff is a valuable tool to prevent caries in infants and toddlers.

To improve oral hygiene in early childhood, more emphasis should be placed on mothers' own toothbrushing and their skills in their children's oral cleaning.

On account of its association with ECC, milk-bottle feeding at night should be limited, whereas prolonged breastfeeding appears to have no such negative dental consequences.

The association between plaque and caries in older children and adults has been poor, however, some studies show that there may be a relationship in younger children. The aim was to study the relationships between dental caries and dental plaque among 12-36-month-olds in Tehran, Iran. A cross-sectional study among a stratified random sample of 504 children aged one to three years from 18 public health centres in Tehran. Mothers were interviewed about their child's date and order of birth, gender, primary caregiver, the mother's age and the educational level of both parents. Dental examination was carried out according to the WHO criteria. Early childhood caries (ECC) was defined as the presence of any dmf teeth. Dental plaque was visually inspected on the labial surfaces of upper central incisors. Data analysis included Chi-square test, t -test, anova and logistic regression modelling. The prevalence of ECC ranged from 3 to 33% depending on age group, with a mean dt of 1.1 for 26- to 36-month-olds. No gender-differences existed in ECC prevalence and mean dt. Dental plaque was visible on at least one index tooth for 65-75% of the children. Presence of ECC was related to the presence of dental plaque (OR = 1.5; 95% CI 1.0-2.3) when controlling for background factors by means of logistic regression. The high occurrence of visible plaque and rather high ECC prevalence call for improvement in oral health promotion programs of the children.