Association between breast-feeding duration and posterior crossbites.

PURPOSE: The purpose of this study was to evaluate the association between breast-feeding duration and the subsequent occurrence of posterior crossbite in Brazilian children. METHODS: A cross-sectional study was conducted involving 714 six- to nine-year-old children. A questionnaire was completed by mothers or guardians of the children concerning the length of time they were exclusively breast-fed and the breast-feeding duration. A clinical examination of each child was conducted to detect posterior crossbite. Data were analyzed using Pearson's chi-square test at a five percent significance level. RESULTS: There was a posterior crossbite prevalence of approximately 15 percent. There was no statistically significant association between posterior crossbite and age or gender ( P >.05). The prevalence of posterior crossbite was higher among children who were not breast-fed (28 percent) than among breast-fed children (13 percent). There was a significant association between posterior crossbite and the length of time that children were exclusively breast-fed and the breast-feeding duration ( P <.05 percent). CONCLUSION: The prevalence of posterior crossbite gradually decreased as exclusive breast-feeding duration increased, and there was a relationship between breast-feeding duration and the occurrence of posterior crossbite.