Objective To analyze the perception of mothers about oral health of their children, as well as to check the influence of demographic variables, perception and preventive practice in oral health of mothers regarding guidance received during pregnancy.Methods Quantitative and cross-sectional field study, with a non-probability sample formed by all mothers who attended the primary healthcare unit of Ijuí (RS), Brazil, from January to July 2014, comprising a sample of 79 women. Self-applied questionnaires were given to these mothers. Data analysis was carried out using descriptive and inferential statistics, the χ2 test at a significance level of 5%.Results The mothers who received dental orientation during pregnancy had greater perception of oral health of their children. The mean age of mothers was 26 years, most of them attended high school education (32.9%) and worked outside the home (60.8%). There was a statistically significant relation between the outcome variable, dental orientation during pregnancy, and the independent variables: schooling level of mothers, occupation, baby’s first visit to the dentist, duration of breastfeeding, beginning of baby’s tooth brushing and knowledge about dental decay (p<0.005).Conclusion Mothers with higher schooling levels and who worked outside the home had more knowledge about oral care, because they received dental orientation during pregnancy. The dental guidance during pregnancy influences the mother in the procedures adopted with their children, as to early oral hygiene, first dentist appointment, duration of breastfeeding, knowledge about the factors that lead to dental decay.