The Study of Treatment Angle's Class II Division I Malocclusion with the Single Maxillary Extraction Orthodontics

Objective:To investigate the effect and indication of single maxillary extraction orthodontics for thetreatment of patients with Angle Class II division I malocclusion.Methods:eighteen patients with Angle Class II division I malocclusion were treated by single maxillary extraction orthodontics.The cephalometric analysis before and after treatment were performed and the data statistically analyzed.Results:After treatment,① the angle U1-SN had increased by 4.84 degrees and the angle L1-MP had increased 2.78 degrees.Z angle had increased by 3.22°;The upper lip and upper incisor were retracted obviously by 1.39mm and 4.06mm respectively.② The profile of the 18 patients were significantly improved.The relationship Was toatally distal between the molars and neutral between the canines.The anterior overjet and overbite Was norma1.Conclusion:Single maxillary extraction orthodontics is suitabale for class II division I patients with less labial tipping of lower incisors and less lower lip protrusion.