The effect of fluorides and caries in primary teeth on permanent tooth emergence.

This study addressed two questions: (i) is there an effect of exposure to fluorides on the timing of emergence of permanent teeth? and (ii) can a difference in timing of tooth emergence be explained by the impact of fluorides on the caries experience of the predecessors? Data were obtained from a long-term follow-up study of the oral health condition in a sample of 4468 Flemish children. Survival analyses with log-logistic distribution were performed to calculate median emergence ages and 95% confidence intervals; four fluoride exposure parameters (fluorosis, use of systemic fluoride supplements, age at which tooth brushing started and frequency of tooth brushing) and caries experience were taken as covariates in the model. The present study indicates that the impact of any of the four fluoride exposure parameters on permanent tooth emergence was relatively minimal. Caries experience in the primary molars had a more pronounced impact on the timing of emergence of the successors than exposure to any of the four fluoride parameters.