Treatment of Angle classII division 2 malocclusion by coil-spring utility arch

Objective:To study the clinical effect of a new method in the treatment of Angle classⅡ division 2 malocclusion.Method: 20 subjects(9 boys and 11 girls aged 10.5～15.8 years old) were treated with coil-spring utility arch.Hooks were weld in the arch and classⅡelastics were used(the force was about 150 ～200 g).The upper molars were moved distally and the lower molars were drifted mesially.The pretreatment and posttreatment cephalometric radiographs were taken in order to measure the distal and mesial movement of the molars.Result:After a mean treatment period of(4.5) months(ranged from 3.4 months to 5.8 months),the classⅡmolar relationship was corrected.The distal movement of the upper molars was 2.16±1.3 mm on average,and the mesial movement of the lower molars was 1.38±0.64 mm on average.Conclusion:Coil-spring utility arch is an effective method in the treatment of Angle classⅡ division 2 malocclusion.Its treatment mechanism is the co-operation of the distal movement of the upper molars and the properly mesial movement of the lower molars.