When the baby has lower teeth wrapped around the upper teeth, the following measures can be taken: First, correct the incorrect feeding posture, avoid sleeping with a bottle, and quit bad habits such as tongue spitting and finger sucking. Second, when the upper and lower front teeth are mildly anti (dentition) or to the edge (dentition), you can apply the bite pry method, between the upper and lower teeth can chew the pencil head and other hard objects, press the lower front teeth to move to the tongue side, push the upper front teeth to move to the lip side, lift the anti (dentition). Third, 2-3 years of age, when the baby formed the anterior milk teeth (teeth together), can wear movable orthodontic appliances, the use of hyperbolic lingual spring to push the upper front teeth to the lip and cheek side, if necessary, the application of extra-oral arch, chin pocket, front traction and other devices to stimulate the full development of the upper jaw, inhibit the lower jaw bone overdevelopment. Fourth, when the baby has molar rebellion (teeth together), it can wear a maxillary spiral arch expander to push the bilateral molars to the buccal side to increase the width of the maxilla.