Effects of early treatment of class Ⅲ malocclusion with magnetic orthodontic appliance / 中华医学美学美容杂志

ABSTRACT

Objective To develop a Class Ⅲ twin-block magnetic orthopedic appliance (TMOA-Ⅲ) and to investigate the treatment effects of this appliance on skeletal Class Ⅲ malocclusion of mixed dentition and early permanent dentition.Methods The sample consisted of 76 Chinese children (42 males and 34 females,mean age 9.1 years) with Class Ⅲ malocclusion caused by maxillary retrognathism,and the subjects were divided into a treatment group and a control group.The treatment group,38 subjects (21 males and 17 females),were instructed to wear TMOA-Ⅲ for 5-8 months (mean 7.5 months) and the control group,38 subjects (21 males and 17 females),did not wear any appliance.Cephalometric radiographs were taken and measurement data were used for analysis.Results Compared with the control group,patients of the treatment group showed a favorable increase of maxilla length and anterior movement (PNS-A,P＜0.001;SNA,A-NPg,P＜0.05),and skeletal Class Ⅲ facial profiles improved (UL-EL,NsPgs-HL,Facial convexity,P ＜ 0.001;LL-EL P ＜ 0.005).Conclusions The results indicate that TMOA-Ⅲ is effective for the treatment of Class Ⅲ malocclusion caused by maxillary retrognathism in mixed dentition and early permanent dentition,which provides another choice for the treatment besides the face mask.