The effect of maxillary protraction with expansion on upper airway and tongue in the treatment of skeletal Class Ⅲ malocclusion
Objective The aim of this study was to evaluate the effects on airway and tongue morphology after using maxillary protraction with expansion in growing skeletal Class Ⅲ patients.Methods Thirty patients(mean age 9.5±1.5 years)with skeletal Class Ⅲ were treated with maxillary protraction with expansion.The cone beam computed tomography(CBCT)were obtained at pre-treatment(Tl)and post-treatment(T2).A three-dimensional structural model of upper airway and tongue were reconstructed.The hard tissues of the maxillofacial region,the airway and the tongue were measured.Results The maxillary length and width increased,the mandibular rotated clockwise,and the hyoid bone moved forwardly and downwardly after treatment(P＜0.05).The volume of nasopharyngeal airway,palatopharyngeal airway and the total volume of upper airway increased compared with baseline(P＜0.05),while there was no significant difference in the volume of glossopharyngeal airway and laryngeal airway(P＞0.05).The tongue volume and intrinsic oral cavity volume increased and the proportion of tongue volume to oral cavity volume decreased after treatment(P＜0.05).Conclusion Maxillary protraction with expansion promotes the growth of maxilla and increases the volume of nasopharyngeal,palatopharyngeal airway.At the same time,the expanded inherent oral volume may lead to the volume of the tongue increases adaptively.
Maxillary protraction with expansionSkeletal Class Ⅲ malocclusionUpper airwayTongueCBCT
NETL
NSTL
万方数据
