A seven-year survival analysis of caries onset in primary second molars and permanent first molars in different caries risk groups determined at age two years.

OBJECTIVE

To investigate in a group of children (n=183) the effect of possible risk factors registered at the age of 2 years on caries development in 7 years of follow-up, and to study associations between risk groups.

MATERIAL AND METHODS

Consumption of candies, use of a nursing bottle at night, use of fluorides, toothbrushing, pacifier sucking, and prolonged breastfeeding (>or=12 months) were recorded at the age of 2 years. The timing of caries onset in different groups was compared by applying a survival analysis method--the survival curves produced separately for selected teeth in different risk groups.

RESULTS

The survival curves of caries onset for both primary and permanent molars were consistently lower for children who consumed candies more than once a week, did not brush their teeth daily, were given a nursing bottle at night or a pacifier at age 2 years. The multivariate survival analysis confirmed that consumption of candies and lack of daily toothbrushing were the factors that had the major impact on caries onset in both primary and permanent molars. Prolonged pacifier sucking (>or=2 years) was related only with short duration of breastfeeding. Children with prolonged use of a nursing bottle at night also consumed candies more than once a week, did not brush their teeth regularly, and did not use fluoride tablets.

CONCLUSIONS

Consumption of candies and inadequate oral hygiene at age 2 years are important long-term risk factors for caries development in both primary and permanent molars.