What Does Laughing Gas Do in Dentistry? Learn About Nitrous Oxide Sedation

People often get confused when they hear of laughing gas uses in dentistry. They often ask what does laughing gas do in dentistry? Visiting a dentist can be an anxious episode for some individuals. Many people even avoid dental treatments for fear of injections and drills. In such cases, conscious sedation is the technique of choice. Through Nitrous oxide, also known as laughing gas, conscious sedation the patient can relax and stay calm during the procedure. The pain signaling receptors are blocked, and the patient doesn’t feel any pain related to the treatment.

Three to five minutes after the supply of gas is turned off; the nitrous oxide exits the body and patient starts gaining consciousness. Laughing gas conscious sedation is considered safe even for children.


The patient is advised to avoid eating a heavy meal at least three hours before the procedure. Let us understand in detail what does laughing gas do in dentistry with its effect and mechanism of action.

Types of dental sedation

There are different levels of sedation that can be used during your dental treatment.

Minimal sedation

During the dental procedure, the patient remains awake and conscious. However, the patient feels very relaxed and extremely calm.

This minimum level of sedation is achieved by using nitrous oxide, sometimes referred to as laughing gas or hippy crack. It is used in combination with oxygen and is delivered through a nose mask (1).

Moderate sedation

During the dental procedure, the patient is still conscious and able to respond and breathe. However, the patient is in a more profound state of sedation or relaxation and will have little to no memory of the procedure.

This type of sedation is administered orally or intravenously and is referred to as sleep dentistry.

Deep sedation

During the dental procedure, the patient will be unconscious and asleep. This type of sedation is achieved through a general anesthetic. After waking up from a general anesthetic, you will have no memory of the procedure (2).

This is usually carried out in a hospital. A qualified medical doctor who has specialized training in anesthetics administers the drugs, controls the length of time you are asleep, and is present during the entire procedure to monitor your breathing, pulse and blood pressure.

How does laughing gas work?

For the administration of nitrous oxide, the dentist places a mask covering the patient’s nose. The mask contains nitrous oxide and oxygen gases which the patients breathe in.

The dentist can adjust the concentration of nitrous oxide to fit the patient’s needs. The gas is provided in increments till the desired action is obtained (3).

Some patients under the influence of nitrous oxide may feel that the time passes more quickly. Patients are also less likely to gag with dental instruments when under sedation.

Furthermore, the patient remains in a relaxed state, and the sedation makes them less likely to move during the procedure. This makes it relatively more manageable for the dentist to perform the procedure.

Nitrous oxide is a mild sedative. Most of the patients do not fall asleep and talk with dental staff. The patient is less likely to remember whatever happened during the procedure.

After the treatment is complete, the dentist turns off the nitrous oxide. The patient is kept on oxygen on for a few minutes. After the dentist takes the mask off, the nitrous oxide will have already exited the patient’s system.

Effects of laughing gas on patients

Nitrous oxide has various effects on the brain. The main effect that makes it the sedation of choice in dentistry is its pain blocking mechanism. It blocks the pain-signaling neurons, thus reducing the acceptance of pain.

Nitrous oxide also increases the activity of GABA receptors, helping the patient stay calm and reducing the anxiety of the patient (5).

Nitrous oxide influences the dopamine release (6). The patient feels happy and in a state of euphoria even after the treatment is over.

However, the effects of nitrous oxide differ from person to person. Some patients feel giddy, and some start laughing out loud. Others feel relaxed and calm. Some can even feel light-headed. For some patients’ their arms and legs feel heavy while others experience tingling in their arms and legs.

Safety of nitrous oxide

Nitrous oxide is safe sedation even for children (7). However, the dentist needs to take a parental consent before administering nitrous oxide on a child. Nitrous oxide is well tolerated, it does not cause allergic reactions, and does not have any lingering effects.

Less than 1% of patients may experience nausea from nitrous oxide. To avoid this, it is advised to avoid eating a heavy meal at least two hours before the procedure. Also, provide all the accurate details of your medical history and about any medications that you are taking.

Patients who have a congested nose or breathing problems are not able to achieve optimal sedation with nitrous oxide mask.

Consultation between a dentist and a patient’s physician is required to ensure the safety of the patient before administering nitrous oxide in the following conditions.


A dentist requires medical consent from the pregnant patient’s obstetrician before administering nitrous oxide. Sedation is best avoided in pregnant females to ensure the safety of both the mother and the fetus (8).

Psychiatric conditions

If the patient is taking medication for a psychiatric condition, it is essential that they speak with their psychiatrist before receiving nitrous oxide. This will help eliminate any form of drug interactions that can affect the patient’s mental state.

Prior substance abuse

Recovering alcoholics and those recovering from substance abuse should consult their drug counselor or psychiatrist. Nitrous oxide is a type of mind-altering substance it could lead to a relapse in such patients (9).

Pulmonary Disease

Treatment with nitrous oxide requires that the patient inhale laughing gas through their nose. Those with breathing problems such as Chronic Obstructive Pulmonary Disease, emphysema, or bronchitis should consult their physicians before receiving nitrous oxide.

Recent surgeries

Patients who have had recent surgeries for eyes or ears; or patients who have recently suffered severe injuries, mainly head injuries, should consult their physician before scheduling a treatment with nitrous oxide.

Sickle cell anemia

Individuals with sickle cell anemia may need to consult their physician for their consent to undergo a dental procedure under nitrous oxide sedation.

Allergic reaction to any medication

There are almost 170 drugs which can interact with laughing gas. That’s why it is essential to inform your dentist about your ongoing medications and medical conditions.

Side effects of nitrous oxide

The minority of patients experience any adverse side effects. The side effects occur only if the nitrous level is too high or if the delivery of the gas is too fast (10). The potential side effects are as follows:

  • Nausea or vomiting
  • Excessive sweating
  • Headaches
  • Fatigue
  • Shivering

Once the procedure is done, and nitrous oxide is turned off, the patient needs to receive oxygen for at least five minutes. This will avoid headache post consciousness.


The oxygen will also help remove any remaining gas from the lungs while assisting the patient in becoming alert and awake. The nitrous gas is eliminated from the body within 3 to 5 minutes after the gas supply is stopped.

The patient can even drive back home after recovery, and they do not need an escort.

Key points to remember

Laughing gas provides conscious sedation wherein the patient is can even talk and understand the instructions given but is unable to feel any pain.

Avoid having a heavy meal at least three hours before the procedure. Mention in detail about any medical conditions or medications while giving out your medical history. Nitrous oxide may not be safe for pregnant women.


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