Incidence of malocclusion between primary and mixed dentitions among Brazilian children A 5-year longitudinal study

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 (Cl) analyses were carried out. Results: The greatest incidence of malocclusion was found in children with malocclusion (94.1%) when compared with those without malocclusion (67.7%) (RR = 1.4 [1.2-1.6]; P < .001). Anterior open bite (RR = 3.1 [1.7-5.8]), posterior crossbite (RR = 7.5 [4.9-11.5]), and overjet greater than 3 mm (RR = 5.2 [3.4-8.0]) in the primary dentition are risk factors for malocclusion in early mixed dentition. Spontaneous correction of the anterior open bite was confirmed in 70.1% of cases. 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.)