Amamentação, uso de chupeta e maloclusão na dentição decídua: estudos na coorte de nascimentos de Pelotas de 2015

Abstract

The objective of this thesis was to investigate the association between breastfeeding and malocclusion, considering the influence of pacifier use. To this end, two articles were developed using data from the Pelotas 2015 Birth Cohort Study (n=3591). The first article aimed to assess whether the protective effect of exclusive breastfeeding on malocclusion in the primary dentition is modified by the duration and intensity of pacifier use. Breastfeeding exposure was collected through information on breastfeeding duration during follow-ups. The outcome, malocclusion, was evaluated using the World Health Organization's criteria. To assess the association between exclusive breastfeeding and malocclusion, which vary according to the duration and intensity of pacifier use, an effect measure modification analysis was adopted through the relative risk due to interaction (RERI). Exclusive breastfeeding showed a protective effect (RR 0.82; 95% CI: 0.70-0.96) on the occurrence of malocclusion when compared to children who never received exclusive breastfeeding. Regarding pacifier use duration, children who used a pacifier full-time or part-time during the first 4 years had a prevalence of malocclusion 8.43 (RR 8.43; 95% CI: 6.78-10.46) times higher compared to children who never used a pacifier, and in terms of use intensity, those who used it full-time had a higher prevalence of malocclusion (RR 2.80; 95% CI: 2.52-3.11). Therefore, the duration and intensity of pacifier use modify the protective effect of exclusive breastfeeding on malocclusion prevalence. The second article aimed to investigate the duration of breastfeeding as a protective factor against the occurrence of malocclusion and its types. The duration of breastfeeding and malocclusions were collected through information during follow-ups, and four types of malocclusion were evaluated according to the Foster and Hamilton criteria: open bite, crossbite, overjet, and canine class II. Prevalence ratios (RR) were estimated using a Poisson regression model. Statistical inferences were based on 95% confidence intervals (95% CI). The lowest prevalence of malocclusion was found in children breastfed for at least 2 years (17.7%), while the highest prevalence was observed in children who always used a pacifier: anterior open bite (88.7%), posterior crossbite (67.1%), canine class II (66.8%), and overjet (30.1%). After adjusting for pacifier use, the protective effect of breastfeeding was nullified. Therefore, the longer the breastfeeding period, the lower the incidence of malocclusion and pacifier use. The findings of this thesis reinforce the harmful effects of pacifier use on occlusal development, even with the practice of breastfeeding.