Once the design of the denture is finalized, it is time to start the preparation. The doctor will adjust and grind some teeth in the mouth according to the design requirements and needs, which is also called dental preparation. The most commonly used tool is the fast handpiece, because of its high speed, noise, easy to cause psychological panic in the patient, coupled with in order to avoid cutting heat production, the use of water cooling method, sometimes the water is easy to choke the throat, most patients are very uncomfortable. Especially when grinding the teeth with nerves, there will be varying degrees of pain and soreness, the patient out of instinct, hoping to pass these feelings immediately to the doctor, but can not speak, the patient’s head often appears in the clinic suddenly turned, or pulling the doctor is operating the arm and other dangerous actions. Because of the suddenness of the incident, the high-speed rotation of the phone can not be stopped in an instant, it is easy to cause oral soft tissue damage. So how can patients undergoing treatment quickly and accurately transfer their feelings to the doctor? When you need the doctor to pause the operation for some reason, always remember to raise your left hand to signal, when the doctor stops the operation, take the phone out of the mouth, and then action to ensure the safety of the treatment. Nasal breathing is not smooth, the pharynx special sensitive patients, can also be informed in advance, so that the doctor is prepared.