常见例句双语例句Methods To adopt screw expansion appliance to gradually expand posterior and anterior dental arch with 18~33 day activation and 3~6 month retainment.方法采用螺旋扩大矫治器进行前牙和后牙的扩弓，加力18～33天，戴用保持器3～6个月。 返回 anterior expansion arch