Factors Associated With Deep Bite Severity in Children With Primary and Mixed Dentition: A Cross-Sectional Epidemiological Study

Introduction: Deep bite is one of the most common vertical malocclusions encountered during childhood and may adversely affect oral function, periodontal health, facial esthetics, and long-term occlusal stability. This study aimed to evaluate the severity of deep bites and identify the demographic, extraoral, and intraoral factors associated with deep bite severity among children aged 5-12 years. Materials and methods: A cross-sectional study was conducted among 1,400 school-going children aged 5-12 years with primary and mixed dentition. The participants were selected using a two-stage proportionate cluster random sampling technique. Deep bite severity was assessed using a study-specific modified four-grade clinical classification system. Demographic characteristics, oral habits, facial profile, body build, lower facial height, lip competence, mentolabial sulcus, upper labial frenal attachment, molar relationship, and overjet were also recorded. Associations were evaluated using the chi-square test and Cramér's V test, and cumulative odds ordinal logistic regression was performed to identify independent predictors of deep bite severity. Statistical significance was set at p < 0.05. Results: Among the 1,400 children evaluated, grade 1 deep bite was observed in 734 children (52.4%), grade 2 in 337 children (24.1%), grade 3 in 259 children (18.5%), and grade 4 in 70 children (5.0%). Significant associations were observed between deep bite severity and oral habits, body build, facial profile, lower facial height, lip competence, mentolabial sulcus, and molar relationship (all p < 0.001). In contrast, upper labial frenal attachment was not (p = 0.341). Ordinal logistic regression identified athletic body build (odds ratio (OR) = 6.505, p = 0.003), decreased lower facial height (OR = 9.966, p < 0.001), increased lower facial height (OR = 3.362, p = 0.006), and increased overjet (OR = 1.255, p = 0.013) as significant independent predictors of greater deep bite severity. Conclusions: Deep bite severity was significantly associated with oral habits, craniofacial morphology, lower facial height, lip competence, mentolabial sulcus, and molar relationships. Athletic body build, altered lower facial height, and increased overjet were identified as independent predictors of greater deep bite severity, highlighting the importance of early clinical assessment for identifying children at risk of greater observed severity.