Estudo longitudinal do desenvolvimento da oclusão entre as fases de dentição decídua e mista e a influência dos hábitos bucais deletérios e da adenóide hipertrófica

Abstract

The aim of this study was 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 and associate to etiologic factors. The individuals, ages 8 to 11 years, were randomly selected from a representative sample. The inclusion criteria were the normal occlusion in primary dentition (150 children) or the following malocclusions (150 children): anterior open bite and/or posterior crossbite and/or overjet more than 3 mm, since that they did not being submitted to orthodontic treatment. During the clinical exam, it was assessed the breathing pattern. A possible upper airway obstruction related to the adenoids was analyzed through a lateral cephalometric radiograph. The presence and the duration of digit and pacifier-sucking habits were evaluated through questionnaires. Descriptive, chi-square, relative risk (RR), and Poisson regression, with robust variance analysis, were carried out at 95%CI. The greatest incidence of malocclusion was identified among children with previous 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] P<.001), posterior crossbite (RR=7.5 [4.9-11.5] P<.001) and overjet greater than 3 mm (RR=5.2 [3.4-8.0] P<.001) in primary dentition are risk factors for malocclusion in early mixed dentition. It was verified that the anterior open bite corrected spontaneously in 70.1% of cases. Posterior crossbite and overjet greater than 3mm showed persistent in 87.8% and 72.9% of children. The risk factors for the occurrence of malocclusion in the early mixed dentition were the presence of malocclusion in the primary dentition (RR=1.31 [1.13-1.52] P<.001), mouth-breathing pattern (RR=1.15 [1.03-1.28] P<.05), and the hypertrophied adenoids (RR=1.12 [1.00-1.26] P<.05). The development of malocclusion in the early mixed dentition was not statistically associated to digit and pacifier-sucking habits (P>.05). Malocclusion incidence was high. Individuals with previous anterior open bite, greater overjet, and posterior crossbite had greater risks of having the same characteristics in the early mixed dentition. The malocclusion incidence increase from primary to mixed dentition was directly related to the presence of malocclusion in primary dentition, mouth-breathing pattern, and hypertrophied adenoids of children.