Abstract: Objective: To explore the orthodontic results of two-phase treatment of Twin Block appliance and Invisalign appliance in the patient with Angle class Ⅱ divison 1 malocclusion, and to provide the basis for the treatment in clinics. Methods: A patient with mandibular retraction accompanied by crowdedness, who was diagnosed as Angle class Ⅱ divison 1 malocclusion, MaoⅡ²+Ⅳ¹+Ⅰ¹ malocclusion was selected, and the curative effect of this method was discussed combined with the literature review. Results: Twin Block appliance and Invisalign appliance were applied for two-phase treatment, then the lateral cephalometric radiograph, the lengths and widths of the dental arches were measured and the measurement values were compared between before and after treatment;the changes of Ricketts esthetic planes of the patient before and after treatment were analyzed. Compared with before treatment, the angle SNB was increased by 1.7°, the angle ANB was decreased by 0.7°, the angle of L1/MP was increased by 8°, and the angle of U1/L1 was decreased by 6°; the distance of U1-NA was increased, while the distance of L1-NB was decreased;the width of middle maxillary dental arch was increased by 3.8 mm, the width of posterior mandibilular dental arch was increased by 3.4 mm, and the lengths of maxillary and mandibilular dental arches were also increased. The results of Ricketts esthetic plane analysis showed the position of pogonion moved forward after treatment. Conclusion: Twin Block appliance and Invisalign appliance as two-phase treatment can be used for the patients with Angle class Ⅱ divison 1 malocclusion, and it can improve the facial profile of patient;the method can achieve the therapeutic purpose while bringing excellent orthodontic experience to the patients.

Key words: angle class Ⅱ division 1 malocclusion, Twin Block appliance, Invisalign appliance, length of dental arch, width of dental arch