Relationships among nasal resistance, adenoids, tonsils, and tongue posture and maxillofacial form in Class II and Class III children

Introduction: The purpose of this study was to clarify the relationships between upper airway factors (nasal resistance, adenoids, tonsils and tongue posture) and maxillofacial form in Class II and III children Methods: Sixty-four subjects (mean age, 9.3 years) with malocclusion were divided into Class II and Class III groups by ANB angle. Nasal resistance was calculated using computational fluid dynamics from cone-beam computed tomography (CBCT) data. Adenoids, tonsils and tongue posture were evaluated in CBCT images. The groups were compared using Mann-Whitney U-tests and Student t-tests. Spearman’s rank test assessed the relationships between upper airway factors and maxillofacial form. Results: Nasal resistance of the Class II group was significantly larger than that of the Class III group (P = 0.005). Nasal resistance of the Class II group was significantly correlated with inferior tongue posture (P < 0.001), and negatively correlated with intermolar width (P = 0.028). Tonsil size of the Class III group was significantly correlated with anterior tongue posture (P < 0.001) and mandibular incisor anterior position (P = 0.007). Anterior tongue posture of the Class III group was significantly correlated with mandibular protrusion. Conclusions: The relationships of upper airway factors differed between Class II and Class III children.

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