Ethical considerations and study design.
D000293:Adolescent; D002648:Child; D002986:Clinical Trials as Topic; D003299:Cooperative Behavior; D004245:DMF Index; D003731:Dental Caries / Q000453:epidemiology / Q000517:prevention & control*; D004990:Ethics, Dental; D006805:Human Experimentation; D006801:Humans; D012107:Research Design; D012189:Retrospective Studies; D013223:Statistics as Topic