Comparative Assessment of Orofacial Myofunction, Strength, and Quality of Life in Children With and Without Anterior Open Bite: The OMBIT Study

Purpose: Anterior open bite (AOB) is a multifactorial malocclusion frequently associated with nonnutritive sucking habits (NNSHs) and orofacial dysfunctions. However, little is known about the specific orofacial strength and endurance profile in affected children. This study evaluated myofunctional history, orofacial myofunctional status, orofacial strength, and oral health–related quality of life (OHRQoL) in children in the mixed dentition stage with AOB, compared to controls without AOB. Method: Sixteen children with AOB in the mixed dentition stage ( M age = 8.2 years) and 16 age- and gender-matched controls participated in this cross-sectional study. Dental and orofacial histories were collected through parental questionnaires. Palatal and occlusal morphologies were assessed using intraoral scans. Orofacial function was examined using the Orofacial Myofunctional Evaluation with Scores (OMES) protocol and ultrasound imaging. Maximum isometric pressure and endurance of the tongue and lips were measured using the Iowa Oral Performance Instrument (IOPI). OHRQoL was assessed using the Child Oral Health Impact Profile–Ortho (COHIP-Ortho). Results: Oral habits (e.g., nail biting, lip licking) were more frequently observed in the AOB group, and parental reports indicated that persistent open mouth behavior was reported more often in children with AOB. Two thirds of the participants had a history of NNSH, with similar prevalence across groups; however, AOB was associated with NNSH cessation at an older age. AOB was associated with higher anterior tongue endurance. No other significant differences were found in tongue or lip strength or endurance, OMES scores, or COHIP-Ortho scores. Conclusions: The absence of group differences in orofacial strength and most endurance measures suggests that, in this sample, mixed-dentition AOB was not accompanied by generalized orofacial strength deficits. These findings support early functional screening and suggest that function-focused orofacial myofunctional therapy, rather than strength-based training, may be a relevant approach in children with AOB.