Nitrous Oxide Sedation - Inhalation Sedation Overview
Nitrous Oxide Sedation Dentistry

Nitrous Oxide Sedation Dentistry

Nitrous oxide sedation dentistry, also known as inhalation sedation, is the most commonly used method for patient relaxation in dental offices. Dentists use nitrous oxide, also known as “laughing gas”, for over 160 years to provide more comfortable and painless dental treatments to their patients. It is estimated that over one third of U.S. dentists use laughing gas to help patients with dental anxiety and phobia.

What is Nitrous Oxide Sedation Dentistry?

Nitrous oxide sedation is the lightest form of dental sedation, but it can provide adequate level of anesthesia and relaxation for most people and for the majority of dental procedures. It involves breathing a mixture of nitrous oxide gas in combination with oxygen which can help anxious patients to become more relaxed and co-operative during treatment without experiencing pain.

Inhalation analgesia, as it is also called, is a method of conscious sedation because the patient remains awake and conscious throughout the procedure. It should not be confused with sleep dentistry which refers to unconscious sedation (general anesthesia).

Nitrous oxide provides minimal sedation which is defined as a drug induced controlled state of minimally depressed consciousness. The patients retain the ability to breath without external help, maintain their protective reflexes and the ability to respond normally to physical stimulation and to verbal commands.

This method of sedation is good for light procedures or routine visits to the dentist. It is best for people with low levels of anxiety.

Who can benefit from Nitrous Oxide Sedation Dentistry

Except of the few patient groups where the use of nitrous oxide is contraindicated, all the others can take advantage of N2O inhalation sedation, but especially the following:

  • Adult patients with mild dental anxiety or dental fear or phobias.
  • Children who are non-cooperative or afraid of the dentist.
  • Special needs patients with functional and cognitive deficits.
  • Patients seeking for an alternative or enhancement to local anesthesia for certain procedures.
  • Patients with hyperactive gag reflexes.
  • Anyone who wants to feel more relaxed and comfortable during dental treatment.

What is Nitrous Oxide – How it works?

Nitrous oxide (N2O) is a colorless, non-flammable gas with a slightly sweet odor and taste. It is used in sedation dentistry because of its combined properties as sedative and anxiolytic (anti-anxiety) agent. Because of its pharmacokinetic properties nitrous oxide has a very rapid effect, and its relaxation and pain-killing properties develop after only 2 or 3 minutes after it is inhaled.

It raises the patient’s tolerance to pain by suppressing the signals to the brain allowing the patient to experience dental treatment free of pain. The other important property of nitrous oxide is to produce an euphoric feeling which is very helpful for patients with anxiety, fears or dental phobia. This state of euphoria often makes people to want to laugh, which is why N2O is usually referred as ‘laughing gas’.


Nitrous oxide was discovered in 1772 by Joseph Priestley who is also known for the discovery of oxygen. Its first use as an anesthetic for dentistry was made in 1844 by Horace Wells, a dentist in Hartford Connecticut, who got his tooth extracted under the analgesic effect of nitrous oxide.

Read more about the "Nitrous Oxide history".


Nitrous oxide sedation dentistry is also known as inhalation sedation, because the patient inhales nitrous oxide through a mask placed over the nose. Actually the patient breaths a mixture of nitrous oxide and oxygen, with the oxygen level always maintained over 30% to avoid hypoxia. The percentage of nitrous oxide is fully adjustable ranging from 30%-70% based on the necessary level of sedation and the patient’s tolerance to the gas. Special equipment is used for the safe administration of N2O.

Read more about the "Nitrous Oxide Sedation Procedure".


Nitrous oxide sedation has become so popular because it has many advantages over the other sedation dentistry methods. Additionally to its effectiveness in anxiety and pain control, the main advantages of N2O include its rapid onset without the need of any preparation, the ability to instantly regulate the depth of sedation, the fast recovery and its low cost.

Read more about the "Advantages of Nitrous Oxide Sedation".


Dental sedation using nitrous oxide can be used by the vast majority of dental patients who need a light to moderate level of relaxation. However there are some contraindications that make N2O sedation dentistry not suitable for some patients groups with breathing or lung problems, drug abusers, women in the first trimester of pregnancy, or patients after a recent eye or ear surgery.

Read more about the "Contraindications for the use of Nitrous Oxide Sedation".

Side effects

Another reason for the popularity of nitrous oxide sedation are the very limited side effects. The most common side effect is nausea, but it can be easily controlled by lowering the percentage of the sedative gas in the N2O/O2 mixture.

Read more about the "Nitrous Oxide Side Effects".


Although inhalation sedation dentistry is considered as the safest relaxation method, some risks still exist. They are mostly related with errors in the proper administration of the gas (with ‘hypoxia’ as the most dangerous one) or complications in patients who are not suitable candidates for using it.

Read more about the "Risks of Nitrous Oxide Sedation Dentistry".

The anesthetic and analgesic effects of nitrous oxide in combination with its anxiolytic properties have helped to reduce the barriers to proper dental care for fearful, phobic, and special needs patients.

next page -> What is Nitrous Oxide? How it Works?
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