Longitudinal analysis of orofacial morphophysiological development and eating behavior in children

Many health changes that manifest in childhood can be perpetuated into adulthood, hence the importance of early diagnosis and monitoring. Thus, two studies were carried out with the purpose of evaluating the orofacial morphophysiological development and eating behavior of pre-school children. The aim of the first study was to verify the influence of removing the pacifier habit using the Clarification and Positive Reinforcement Method on the development of oro-myofunctional functions and dentofacial morphology. Sixty preschoolers (mean age of 4 years) were included, divided into two groups: pacifier group (n = 28) and control group (n = 32). Both groups were evaluated and followed up at baseline, 6 and 12 months. The bite force and lip pressure were determined with specific dynamometers. Masticatory function was assessed by the Assessment and Observation of Chewing instrument, breathing by the Myofunctional Orofacial Assessment protocol with Scores, and the speech and swallowing functions by the Orofacial Myofunctional Assessment (MBGR) protocol, being recorded by video and evaluated by a speech therapist. Sensitivity thresholds for sucrose and urea were measured using a methodology developed for 3- to 6-year-old children and occlusion was assessed by dental casts. The two-way ANOVA Mixed Model test was used for statistical analysis. Bite strength and lip pressure did not differ between groups. Children with pacifier habits showed worse performance in chewing and breathing functions at the beginning of the study; after removing the habit, they showed significant improvements in these functions, an increase in the transverse distance from the maxilla and a decrease in the frequency of malocclusion. However, masticatory function was underperformed than that of the control group at the end of 1 year. Sucrose sensitivity was higher in the control group at the beginning of the study, changing over time and showing similarity between groups after 1 year, while bitter sensitivity did not differ between groups. The removal of the pacifier habit at age 4 was important for the oro-myofunctional development, correcting many changes initially found; however, changes in masticatory behavior persisted one year after the habit was removed, highlighting the importance of early habit interruption. The second study was developed during a research internship abroad, considering that exposure to early life adversity can influence food consumption, although the neurobiological basis of this effect is not fully understood. To this end, a polygenic risk score was created based on the coexpression of a dopamine D4 gene network in the striatum and we investigated whether its interaction with a cumulative score of postnatal adversity is associated with food intake in healthy children participating in two birth cohorts: "MAVAN" from Canada (n = 129; 62 boys) and "GUSTO" from Singapore (n = 340; 179 boys). The network of genes co-expressed with DRD4 in the striatum showed to be a moderator of the influence of early stress on children's food intake. We also found significant changes in the body mass index in the 1-year follow-up, possibly as a result of the pattern of food intake (AU)