In recent years, these conditions have been associated with a negative impact on children’s quality of life [8, 9, 10, 11]. Cross-sectional studies [12, 13, 14] demonstrated that dental caries have been associated with a negative impact on the quality of life of children from different age groups [15, 16, 17] So far, only one study, including 3- to 5 year-old children  had used a case-control design to evaluate the association between dental caries and negative impact on oral health-related quality of life (OHRQoL). A case-control study provides adequate statistical power. This power depends not only on the number of cases and controls, but also on the distribution of the exposure of the population at risk and on the relative risk of disease the study aims to detect . Instead of measuring relative risk of disease based on exposure, a retrospective case-control study allows us measure the odds of exposure based on disease.