Relaxing gas: Nitrous Oxide & Oxygen in Dentistry

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This is a great, safe technique, perfect for the ‘dentally anxious patient’ or even for just relaxation during a dental procedure.

What is it and how is it ‘taken’?

Dentists have been offering patients ‘gas & air’ or ‘relaxing gas’ ( Nitrous Oxide mixed with Oxygen) for over fifty years.  It acts as a mild to moderate relaxing sedative and is not an anaesthetic.

Generally it is administered in a 50/50 ratio of the two gases , although the level can be adjusted to suit the patient’s individual level of tolerance .

It is important to know that it cannot be given with less than 30% Oxygen in the mix , which is a 50% greater level than  in normal air . If the Oxygen supply runs out … the Nitrous Oxide cuts out immediately. That is what makes it so safe .

This ‘relaxing gas’ mixture is breathed  through tubes leading to a loosely fitting nose piece . As the patient does not lose consciousness or control , they can ask for the nose piece to be removed at any time if they wish.

Why use it ?

Dental Anxiety:  It is very effective  in calming dentally anxious patients, whether it’s ‘fear of the needle’,  of pain, the vibrations of the drill or even ‘just the thought’ of seeing the dentist’!

Heightened Gag Reflex:  It reduces (but importantly, does not ‘eliminate’) the gag or choking reflex . Some patients have such a sensitive gag reflex that it can make it almost impossible to carry out treatment particularly at the back of the mouth. This gas makes a huge difference to dental treatment acceptance and tolerance in such individuals.

Good feeling: for most patients ( even if not scared and anxious  about dentistry) do find the experience ‘hardly pleasant’ and would rather not be in the dental chair . The experience of breathing this ‘relaxing gas’ can be so pleasant and relaxing that, in the absence of dental treatment pain ( which modern dentistry can achieve) , the dental visit can even be a pleasant experience , believe it or not .

Distracting / relaxing music of the patient’s choice can be given simultaneously ( in noise cancelling headphones, making  the experience is even better ! If the ‘worst’ part of a dental visit is simply having to keep your mouth open for a while,  that’s not too bad, is it ?

What to expect?

The feeling one should ‘expect’ is one of ‘floatyness and detachment’, calmness and possibly euphoria  (which is why it is sometimes called ‘happy gas’). Generally , there is a feeling of ‘caring less’ about what is going on (dentally).

At the end of the procedure , the Oxygen level is increased back to 100% for about two to five minutes and the patient very quickly  returns to normal. He or she can go back to work pretty well straight away.


  • Patient must breathe through the nose ( otherwise it is ineffective).
  • Some people perceive the nose piece to be ‘claustrophobic’.
  • People who admit to being ‘control freaks , may assume they will lose control … actually that never happens!


  • Easy and quick to administer , with the effect ‘kicking in ‘ quickly….and full recovery is very fast.
  • Remarkably safe ; it is NOT retained in the body …. so there are almost never any after effects  ( no ‘hangover’ effect).
  • It is easy to adjust levels to suit individual patient .
  • The important gag / swallowing reflexes are not eliminated.
  • Almost all patients feel very ‘good’ during its administration and more relaxed afterwards.
  • Patients can return to work  immediately afterwards .


This technique, that has been around for a long time has almost no ‘downsides’. At the most, it  can make all the difference between acceptance  or rejection/avoidance of essential or even elective dental care.  At the least, it can turn the dental experience from a unpleasant one that has to be ‘tolerated’ to a relaxed , even pleasant one . How often can one lie back , feel really relaxed listening to great music… with no access to a mobile , computer or phone?

It has been estimated that about 30% + dentists in the USA offer this technique , yet in the UK it is extremely rare.  Why?  It is so safe , not that costly to the patient and immediately ‘reversible’.

It is almost the ‘perfect’ aid for use in the practice of Dentistry . In the opinion of this author every dental practitioner should be trained in its use and offer it in his practice. It is as important as local anaesthetic.



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