Laughing gas mainly plays a sedative role, many patients are more fearful during anesthesia, and more fearful during tooth extraction, in order to reduce this fear, you can let the patient inhale laughing gas in advance, so that the patient is in a relaxed, more comfortable state. When the anesthetic is injected, the patient does not feel the needle sticking, so the result is good. Most of the patients are so, and does not exclude some of the effect is poor, but the reason why the effect is poor, is due to physical problems or inhalation does not cooperate, inhalation does not cooperate is mainly reflected in the children, the general effect of adults are very good, more relaxed, basically do not feel the pain, in a relaxed and comfortable environment to complete the treatment. Laughing gas is very popular in Europe and the United States as a routine, effective and comfortable means of treatment.