The impact of thumb sucking on the stomatognathic system

Abstract

Introduction: Malocclusion caused by thumb-sucking arises from the effect that this habit has on the oral cavity and depends on several factors.
Objective: To evaluate the impact of thumb-sucking on the stomatognathic system in children aged 6 to 8 years.
Method: An observational, descriptive, cross-sectional study was conducted among children at the “Sarah Cordoneda García” elementary school, affiliated with the “Epifanio Rojas Gil” Polyclinic in the municipality of San Luis, during the period January 2024–December 2025. Population: (N=245) children enrolled at that school. Purposive non-probabilistic sample (n=80), according to predefined inclusion criteria. Summary measures were used for qualitative variables (absolute frequencies and percentages).
Results: The majority of patients were 6 years old (46.3%), female (35%), and had a thumb-sucking habit (58.8%). Most children with this habit (27.5%) were not breastfed (46.3%). Based on intensity, passive thumb-suckers were most common (66%); based on frequency, intermittent sucking was most common (48.9%). Anterior open bite (60%) and vestibular inclination of the incisors (56.3%) were the most frequent dento-maxillofacial anomalies, primarily among thumb-suckers (43.8% and 37.5%, respectively). The dolichofacial biotype (53.8%) predominated in the presence of the thumb-sucking habit (38.8%).
Conclusions: Thumb sucking was present in a large portion of the study sample, predominantly among girls. Most exhibited an anterior open bite and vestibular inclination of the upper incisors. The greater the frequency and intensity of thumb sucking, the more severe the anomalies presented.