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How Does Nitrous Oxide (Laughing Gas) Work?


Your dentist may suggest nitrous oxide as a sedative during dental procedures. Also known as laughing gas, nitrous oxide is generally a safe method of sedation that relieves pain and discomfort, while you remain conscious.

Most people, including children, can tolerate nitrous oxide with few, if any, side effects. Before you agree to any procedure, though, you should be aware of how it works and what to expect, so you can make an informed decision about whether it's right for you.

What is Nitrous Oxide?

Nitrous oxide is a chemical compound that forms a colorless, non-flammable gas. When it's combined with oxygen and inhaled in small amounts, it has proven to be a safe method for managing pain and anxiety in dental patients. Nitrous oxide was introduced to surgical and dental practices in the mid-1800s and since then has become the most-used gaseous anesthetic in the world.

Nitrous oxide is a form of "conscious sedation"; you're still awake and responsive when it's administered, but it has a relaxing, calming effect that relieves anxiety and reduces pain. It may also induce a mild feeling of euphoria -- that's why nitrous oxide is sometimes referred to as "laughing gas". These effects wear off quickly, once the source is removed.

How Nitrous Oxide Works

Nitrous oxide is an anesthetic gas that dulls the pain receptors in the brain. Used on its own in high concentrations, it induces loss of consciousness. When nitrous oxide is mixed with oxygen, it relieves pain without causing unconsciousness.

This mixture of "gas and air" is inhaled, using either a face mask or mouthpiece. It enters the bloodstream within minutes, producing the analgesic -- pain relieving -- effect. Once the mask or mouthpiece is removed and inhaling nitrous oxide stops, it's exhaled quickly through the lungs. Inhaling undiluted oxygen for another few minutes helps expel any gas that remains in the lungs.

How Nitrous Oxide is Administered

When used for dental procedures, nitrous oxide is administered through a small face mask that fits over your nose. At first, pure oxygen will be applied, and then the nitrous oxide mixed with oxygen.

Your dentist will remind you to breathe normally through your nose; within a few minutes you will feel the effects. You may feel lightheaded or a tingling in your arms and legs at first. Some people say that their limbs feel heavy and children often report feeling like they were on a "space ride.”

You should feel calm and comfortable, while being able to hear and respond to your dentist. Your breathing rate and consciousness is monitored throughout the treatment. After the nitrous-oxygen mixture is stopped, pure oxygen is administered for several minutes. You should return to the state you were in before nitrous oxide was administered by the time you leave the office.

Benefits for Dental Procedures

Nitrous oxide is a safe sedative with predictable results, with the benefits of keeping patients undergoing dental treatment responsive, but comfortable, so that they can tolerate long, complex procedures with equanimity. It also helps children keep still through treatment.

Nitrous oxide sedation can also be helpful for patients with special health care needs, especially when other anesthetic methods are problematic.

Cautions for Nitrous Oxide

Nitrous oxide may not be suitable for some situations. For example, if you're ill with a cold, or congested, or have any medical condition that affects respiration, nitrous oxide isn't advisable. Women in the first trimester of pregnancy shouldn't have nitrous oxide sedation. Some children don't want a mask over their face, or may become stressed at "losing control.”

Let your dentist know if you're taking any medication, including prescription, over-the counter, and alternative therapies, or whether there has been any change in your medical history since your last visit. You should also mention any drug allergies or dependencies, past and present.

Together, you can decide whether nitrous oxide is right for you.

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