Farquhar & Milnes: Use of laughing gas can help calm a nervous patient

This second column in our sedation series will focus on the use of nitrous oxide and oxygen (N20/02), often referred to as “laughing gas,” as a sedation agent.

This second column in our sedation series will focus on the use of nitrous oxide and oxygen (N20/02), often referred to as “laughing gas,” as a sedation agent.

Many children when faced with dental treatment will cope well and be successful.

Other children may experience anxiety to varying degrees which will necessitate, in addition to appropriate behaviour guidance techniques, some type of pharmacologic intervention, or sedation.

There are many techniques throughout a dental appointment that help the dental team predict what a child’s response will be to the stimulation that generally accompanies restorative treatment.

For example, if a child is able to cooperate for radiographs and will readily interact with members of the dental team, success if much more likely than if a child will not make eye contact or sit cooperatively in the dental chair.

If a child is able to cooperate for the initial dental consultation but exhibits mild anxiety, then we can predict that the likelihood of having a successful treatment appointment  that involves minor treatment  is moderate to high.

If, however, the treatment recommended is more extensive and may involve some discomfort, then the chance of having a successful appointment may be increased by adding nitrous oxide and oxygen to the mix.

Utilizing nitrous oxide/oxygen sedation for dental treatment is a safe and effective method of behaviour management.

It is used to increase the likelihood that a child will cope successfully during the appointment. This helps us to create a positive dental experience.

Laughing gas, which is colourless, is mixed with oxygen and delivered through tubing connected to a soft rubber nasal hood that fits comfortably over a child’s nose.

The child must be able to breathe consistently through their nose when their mouth is open.

Children who cannot manage this, for whatever reason, are not candidates for nitrous oxide and oxygen analgesia.

While nitrous oxide/oxygen is being administered, the effects felt by the child are happiness or euphoria, relaxation and tingling of the extremities and/or lips.

Because there is individual variation in a child’s response to the medication, the dose can be adjusted so that the child remains in a relaxed state depending on the level of stimulation of the procedure.

When the laughing gas is stopped, the child continues breathing oxygen for three minutes as the nitrous oxide leaves the child’s system.

After three minutes, the laughing gas is out of their system. However, a child may remain dizzy for up to five minutes due to the combination of laying back and the minimal residual effects of the laughing gas.

Ten minutes after the appointment, the child should be fully back to his/her pre-appointment state.

A child should remain under parental supervision for the remainder of the day and avoid any activities which require significant coordination, such as bike riding or swimming.

The advantages of using nitrous oxide include mild relief of anxiety, and an increase in attention span by creating the illusion that time is passing very quickly.

Often a child will be very easily distracted or may even decide to drift off to sleep.

The disadvantage of using laughing gas in the dental office setting is the possibility of nausea and vomiting following prolonged use ( 45 minutes to an hour) and/or high concentrations of nitrous oxide, especially when the child has a full stomach.

Because of the possibility of nausea during treatment, it is recommended that a child has no solid food for six hours before the appointment, and clear fluids up to two hours before the appointment.

The success of the nitrous oxide/oxygen sedation is dependent on a child’s ability to breathe clearly through his/her nose.

Any increase in congestion due to colds, fever, cough, runny nose or seasonal allergies will reduce the effectiveness of the treatment.

If treatment with laughing gas has been recommended for your child, please inform your dental office of any changes in health before the appointment so the possibility of rescheduling to a time when your child is healthy can be discussed.

In summary, nitrous oxide and oxygen analgesia has been in use in dentistry for 150 years.

Our profession has proven that, in the right situation, nitrous oxide and oxygen is useful adjunct to creating successful and positive dental experiences.



Alan Milnes and Terry Farquhar are certified specialists in pediatric dentistry at 101-180 Cooper Rd.




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