Morphological and functional abnormalities of the orofacial sphere associated with thumb sucking in children aged 3 to 10 years old in Yaounde, Cameroon

INTRODUCTION: thumb sucking is one of the most common oral habits in infants and children. In our context, little is known about the effects of prolonged thumb sucking on the orofacial sphere. Objective: determine the prevalence of thumb sucking and, identify the morphologic and functional abnormalities of the orofacial sphere associated with the duration and frequency of thumb sucking in children aged 3 to 10 years. METHODS: a cross-sectional and analytical study was carried out in the pediatric units of the District Hospitals of Biyem-assi and Efoulan from February to June 2020 in children aged 3 to 10 years. Recruitment was consecutive, not probabilistic. After obtaining informed parental consent, a clinical examination was performed and the criteria retained were based on the ANGLE classification of the malocclusions. Socio-demographic, socio-economic, clinical characteristics were collected and morphological and functional abnormalities were observed. Statistical analysis was performed using SPSS software version 23.0. The significance threshold was set at 5%. RESULTS: of the 116 enrolled children; 74 girls (63.79%) and 42 boys (36.21%) with a mean age of 4.80 ± 0.5 years. The highest proportion of thumb sucking was found in firstborn children (n=46, 39.65%), and in those who breastfed for less than 6 months (n=99, 85.62%). The prevalence of thumb sucking was 17.4%. Using the multivariate analysis, class II division 1 canine occlusion [OR=1.52 (1.27-2.68), p=0.03] and decreased overbite [OR=4.5 (2.5-9.3), p=0.001] while class II division 1 canine occlusion [OR=2.59 (1.3-10.1), p=0.009] and increased overjet [OR=1.89 (1.06-6.75), p=0.005] were independent morphologic abnormalities significantly associated with the frequency and the duration of thumb sucking respectively. There was no association between the duration and frequency of thumb sucking and the functional abnormalities. CONCLUSION: thumb sucking is more common in girls and the likelihood of thumb sucking decreases with age. The prevalence of thumb sucking was 17.4%. The malocclusions observed in our population are class II division 1 canine relationship, decreased overbite and increased overjet.