RESUMEN
OBJECTIVE: To investigate the association of finger and pacifier-sucking habits, breathing pattern, and adenoid size with the development of malocclusion in primary dentition. MATERIALS AND METHODS: A case-control study was carried out involving 300 preschool children, ages 3 to 6 years, randomly selected from 10 public and 10 private preschools from a large representative sample of 745 children. The study was developed to identify risk factors associated with the development of malocclusion. The case group (n = 150) was composed of individuals with at least one of the following malocclusions: anterior open bite, posterior crossbite, or overjet of more than 3 mm. The control group (n = 150) was made up of individuals without malocclusions. Other variables were assessed through questionnaires about oral habits, including the use of a dummy, finger sucking, duration of these habits; mouth-breathing analysis; and a lateral cephalometric radiograph to evaluate the airway obstruction related to the adenoids. Multiple logistic regression analyses were performed. Statistical significance was P < .05. RESULTS: The risk factors for the occurrence of malocclusion in preschool children were duration of pacifier-sucking after 2 years of age (OR = 14.7) and mouth-breathing pattern (OR = 10.9). No significant associations were found between hypertrophied adenoids or finger-sucking habits and the occurrence of malocclusion. CONCLUSIONS: 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.