Importance: Testing the long-term usefulness of a childhood intervention and determining the best age of implementation are important for translation and policy change.
Objectives: To investigate among children aged 3 years the long-term effectiveness an intervention that aimed to reduce dental caries among South Australian Aboriginal children and to assess if children in the delayed intervention (DI) group had any benefit from the intervention from ages 2 to 3 years and if the intervention usefulness was greater when delivered between pregnancy and age 2 years (immediate intervention [II] vs ages 2 to 3 years [DI]).
Design, Setting, And Participants: Secondary analysis of a randomized clinical trial.