Nitrous oxide is a sedative gas that is used for dental treatment. It is a mild relaxant, and is very helpful if you find dental treatment stressful.
the mask is worn on the nose
If you have true dental phobia, this will probably not be strong enough for you, and you will need sedative medications taken by mouth (often referred to as sleep dentistry), or possibly intravenous sedation or general anesthesia. See our page about sedation dentistry for a fuller discussion of these options.
Nitrous oxide is breathed through a mask placed over your nose. The dentist usually starts out with a low concentration and then gradually increases it until you feel the desired effect. While you're receiving the gas, it's good to give the dentist feedback on its effects. You can strengthen its effect by breathing more deeply. You can also lessen the effect by breathing more through your mouth. But it's best to let the dentist adjust the amounts, because he or she will take note of the concentration that works best for you and will then be better able to treat you.
This works well for people who have trouble getting numb. If you've had the experience where you've required multiple injections of novocain and still felt the drilling in your teeth or the tooth extractions, nitrous oxide will strengthen the anesthetic somewhat and you probably won't feel any pain during your dental appointment.
One of the chief advantages of nitrous oxide gas over pills taken for conscious sedation dentistry is that there is no lingering effect. Within two minutes after the gas is turned off, you can get up and go about your normal activities. You can drive home, go back to work, or whatever you need to do.
Possible disadvantages of nitrous oxide
There's not really much that can go wrong with this gas. In the early days, it was possible to asphyxiate someone by giving them too much of the gas and not enough oxygen. All of today's delivery machines, however, have a fail-safe mechanism that prevents them from delivering less than 20% oxygen and thus asphyxiation is impossible.
If it is given in too high a dosage, the patient can experience nausea and can vomit. Dentists can prevent this side effect by continuing to check with the patient as to how they feel before raising the concentration and then keeping a record of the concentration that works best for each individual. In over twenty years of using nitrous oxide with patients every day, I never had an instance of a patient vomiting.