回复：提上来再问：小孩要整牙，目前还没见过任何的整牙医生

You don't need to tell the doctor you are simulataneously seeking advice from other orthodontists.

Just call and tell the receptionist you are planning for an orthodontic treatment (整牙）, and schedule an appointment. Some orthodontists might suggest extraction of premolars, some might not. Then choose the one you like the most, and schedule the 2nd appointment with him/her and start the treatment. It costs about $5000--$6000. So put some money in the medical flexible spending account in the year you will start the treatment if you want to save the tax money. Also check with your dental insurance to see how much it covers (usually the orthodontist's financial advisor will check for you).