The malocclusion in the primary dentition in preschool children was directly related to the duration of pacifier-sucking after 2 years of age and the mouth-breathing pattern.

Objective: To determine the incidence of malocclusion in a 5-year follow-up of school children and verify the hypothesis that individuals with previous malocclusion are more prone to maintain the same characteristics in the transition from primary to mixed dentition. Materials and Methods: School children, ages 8 to 11 years, participated. Inclusion criteria consisted of normal occlusion in primary dentition or subsequent malocclusions, anterior open bite and/or posterior crossbite and/or overjet measuring more than 3 mm, and that subjects had not submitted to orthodontic treatment and adenoidectomy. Data collection was based on evaluation of occlusion in school children in the actual stage of mixed dentition. Descriptive, Chi-square, and relative risk (RR) 95% confidence interval (CI) analyses were carried out. Posterior crossbite and overjet greater than 3 mm were persistent in 87.8% and 72.9% of children. Conclusions: Malocclusion incidence was high. Individuals with previous anterior open bite, greater overjet, and posterior crossbite had greater risk of having the same characteristics in the mixed dentition. (Angle Orthod. 2012;82:495-500.)