Changes in toothbrushing and factors associated with less than twice daily toothbrushing by the age of four in the FinnBrain Birth Cohort Study.

This study examined toothbrushing and its associated factors in children aged 1-4 years, using data from 306 mother-father-dyads and their 308 children participating in the FinnBrain Birth Cohort Study. Longitudinal multivariable regression analysis was conducted using the generalized estimating equation method to model the outcome, parent-reported brushing of a child's teeth less than twice daily at the child's age of 12, 24 and 48 months, controlling for the intraindividual correlation between repeated measurements using compound symmetry (correlation structure). The independent variables as time-varying covariates from 12 to 48 months were mother's and father's own toothbrushing, couple relationship satisfaction, number of positive life events of father, and fixed covariates were number of siblings, education level of mother and age of parents. Among the children, 50% had stable good and 16% stable poor toothbrushing habits from 1 to 4 years. Both parents' less than twice daily brushing was strongly associated with less than twice daily brushing of a child's teeth. The strength of the association between brushing mother's own and the child's teeth varied across time, whereas this association in fathers remained consistent. Early family-based intervention is crucial for promoting parents' own brushing habits and thereby supporting children's oral hygiene.