An observational cross-sectional study was carried out with the aim of determining associations between quality of sleep and harmful oral habits among children aged three to six years. This study was conducted in compliance with the Brazilian National Health Council/Ministry of Health guidelines contained in Resolution 196/96 and received approval from the Human Research Ethics Committee of the Universidade Metropolitana de Santos (Brazil) under process number 026/2010. Parents/guardians of all participants were properly informed regarding the objectives of the study and signed a statement of informed consent.
Fifty children (3 to 6 years of age) from a private school in the city of Sao Paulo were evaluated by means of two questionnaires administered to parents/guardians: The "Undesirable Habits Questionnaire", composed of 15 investigative questions on harmful oral habits as well as dietary and psychological factors, and the Sleep Habits Questionnaire.6 The data were submitted to descriptive analysis. The chi-square test was employed for the categorical variables and analysis of variance (ANOVA) was carried out to compare mean values. The Student's t-test was used for all analyses, with the significance level set at 5%. The SPSS 12.0 program for Windows was used to analyze the results.