Correlation Between Tongue Morphology and Dental Arch Dimensions in Skeletal Class I and Class II Malocclusions: A Cephalometric Study.

INTRODUCTION

Orthodontic stability depends on the balance between soft tissue forces and skeletal structures. The tongue, which is a key component of the oral musculature, influences the dental arch dimensions and occlusal relationships. An abnormal tongue posture is linked to malocclusion and altered craniofacial development. This study aimed to evaluate tongue morphology and its correlation with dental arch length (AL), arch width (AW), and palatal height (PH) in skeletal Class I and Class II patients.

MATERIALS AND METHODS

A prospective, observational cross-sectional study was conducted at the Department of Orthodontics from March 2022 to July 2024. A total of 80 subjects (40 Class I, 40 Class II) aged 18-30 years were included in the study. Cephalometric radiographs were obtained using a Carestream CS 8100 SC X-ray scanner (Carestream Dental, Atlanta, USA). Barium sulfate solution was applied to the tongue to enhance visibility. Tongue measurements, including tongue length (TL), tongue height (TH), posture, and position relative to the lower incisors and pharyngeal wall, were recorded. The transverse dimensions of the dental arch were measured using digital callipers on the dental casts. Intra-observer reliability was assessed using the intraclass correlation coefficient (ICC). Data analysis was performed using the Mann-Whitney U test and correlation analysis.

RESULTS

Skeletal Class I patients had significantly greater TH, decreased TL, and higher tongue posture than Class II patients. In contrast, Class II individuals exhibited lower tongue posture, increased TL, a greater distance between the tongue and lower incisors, and a reduced distance to the pharyngeal wall. Class I patients also had significantly greater maxillary AL and AW, whereas Class II patients demonstrated deeper palatal vaults. Correlation analysis revealed that tongue morphometric variations influenced AL and AW across both skeletal patterns, with the tongue position affecting maxillary constriction in Class II patients.

CONCLUSION

Class II patients exhibited a lower tongue posture, increased TL, and deeper palatal vaults, which may contribute to maxillary constriction and malocclusion. These findings emphasize the role of tongue posture in arch development and the need for myofunctional therapy in Class II treatment. Future studies using three-dimensional imaging are recommended.