Objective The aim of this retrospective study was to evaluate the clinical efficacy of treatment protocol with extraction of maxillary first premolar and the mandibular second molar in the correction of bony class Ⅱ open bite. Methods 12 patients with bony class Ⅱ open bite cases, 4 males and 8 females, mean age is 15.6 years old, they were treated with extraction of maxillary first premolar and the mandibular second molar and the straight wire appliance. All the lateral cephalometric photos before and after treatment were analyzed. Results Satisfactory results were achieved in 12 patients after treatment, significant improvement of facial profile, normal bite, normal jet and counterclockwise rotation of the occlusal plane were achieved, mandibular plane angle became smaller. Conclusion The clinical efficacy of treatment protocol with extraction of maxillary first premolar and the mandibular second molar in the correction of bony class Ⅱ open bite was effective and stability.
