Effect of maxillary anterior traction combined with spiral arch expander on correcting Class Ⅲ malocclusion in children with mixed dentition using a 3D modeling system
Yuan Yuan
Feng Mei
Lei Jing
Gao Qiang
Suo Qianqian
Fan Yongbo
Wu Lixin
Yang Ying
Abstract：Objective To explore the effect of quantitative analysis of maxillary anterior traction combined with spiral arch ex-pander on correcting Class Ⅲ malocclusion in children with mixed dentition using a 3D modeling system,in order to provide a theoretical basis for clinical optimization of correction regimen.Methods From October 2022 to August 2024,54 children with skeletal Class Ⅲ malocclusion in mixed dentition were included.All children received rapid maxillary expansion with expansion screw and then received maxillary anterior traction correction.Maxillofacial cone-beam CT(CBCT)examination was performed before treatment and at 3 months after expansion.Three-dimensional reconstruction and registration were performed on data,and the changes of hard tissue,airway volume,average cross-sectional area of upper airway and morphological changes of up-per airway were measured before and after treatment.Results At 3 months after expansion,horizontal distance from the an-teroinferior corner of the third cervical vertebra to the hyoid bone in the midsagittal plane(C3-H)was decreased significantly(P＜0.05),while vertical distance from the anteroinferior corner of the third cervical vertebra to the hyoid bone in the midsag-ittal plane(C3Me-H),intercanine distance from the anteroinferior corner of the third cervical vertebra to the maxillary canines(3-3),inter-second primary molar distance from the anteroinferior corner of the third cervical vertebra(V-V),inter-first per-manent molar distance from the anteroinferior corner of the third cervical vertebra(6-6)and maxillary arch length were in-creased significantly(P＜0.05).The volumes of Vnasopharynx,Voropharynx and Vtotal were enhanced significantly at 3 months after ex-pansion(P＜0.05),and there was no statistical significance in Vthroat between groups(P＞0.05).At 3 months after expan-sion,the mean cross-sectional area(mCSA)of the nasopharynx and oropharynx were significantly risen(P＜0.05)while the mCSA throat was significantly reduced(P＜0.05).At 3 months after expansion,AP/LR oropharynx was enhanced signifi-cantly(P＜0.05)while AP/LR throat was decreased significantly(P＜0.05),but there was no statistical significance in AP/LR nasopharynx between groups(P＞0.05).The Vtongue and Vcavum oris proprium of children at 3 months after expansion were elevated significantly while the Vtongue/Vcavum oris proprium was declined significantly(P＜0.05).Conclusion CBCT-based 3D modeling analysis can effectively evaluate the three-dimensional structural changes of hard tissue,airway and tongue in children with skeletal Class Ⅲ malocclusion in mixed dentition treated by maxillary anterior traction combined with spiral arch expand-er,confirming that maxillary anterior traction combined with spiral arch expander correction has good clinical application value.
Keywords：Skeletal Class Ⅲ malocclusionMixed dentitionMaxillary protractionSpiral arch expanderRapid maxillary ex-pansionMaxillofacial cone-beam CT
Publication Date：2025-05-20
Online Publishing Date：2025-09-04(First online date of this platform, not the publication date of the document)
Pages：7( 102-108 )