Laughing gas is sometimes thought of as something for children, but many adults use it too, especially those who feel tense in the chair, gag easily or dread longer appointments. You stay awake and can talk throughout. Within a few minutes most people feel calmer and a little floaty, and the effect fades quickly once the gas is turned off.
A light sedation you stay awake for
Nitrous oxide, also known as happy gas or relative analgesia, is breathed through a small mask over the nose, mixed with oxygen. A review in Anesthesia Progress (Becker and Rosenberg, 2008) describes it as the most commonly used inhalation agent in dentistry, with an impressive safety record when used on its own for minimal and moderate sedation of apprehensive dental patients. On its own it does not reliably produce general anaesthesia, so you will not be put to sleep.
Because it dissolves poorly in the blood, nitrous oxide reaches the brain quickly and leaves the body quickly. That is why it can be turned up or down during the visit, and why the effects wear off soon after it stops.
What you may notice
After a few minutes of normal breathing through the nose, people commonly describe feeling relaxed, warm and slightly drowsy, sometimes with tingling in the hands and feet. Time can seem to pass more quickly. You remain aware of what is happening, can answer questions and can signal if you need a break. The nickname comes from the giggly feeling some people get, though most simply feel calm.
Side effects are uncommon. A few people feel queasy, and very occasionally someone may vomit, so a light meal beforehand is better than a heavy one.
Who it tends to suit
Nitrous oxide is often a good fit for adults with mild to moderate dental anxiety, a strong gag reflex, or difficulty staying still through a longer appointment such as several fillings or a deep clean. Our guide to managing a gag reflex has other practical tips if gagging is your main worry.
It is not right for everyone. A blocked nose makes it hard to breathe the gas, and some medical conditions mean another option is safer. Tell your dentist if you are or might be pregnant, so they can advise on timing and the safest approach. That is why your medical history is checked before it is offered.
How it compares with other options
| Option | How deep | How long it lingers | Getting home |
|---|---|---|---|
| Happy gas (nitrous oxide) | Light | Fades within minutes of stopping | An escort is usually not needed; ask before driving |
| Oral sedation | Light to moderate | Several hours | You need someone to take you home |
| IV sedation | Moderate | Rest of the day | You need someone to take you home |
At Lumi we offer happy gas, inhaled pain relief, oral sedation and IV sedation; we do not provide general anaesthetic. Our overview of sedation options for anxious adults and our guide to IV sedation explain the alternatives, and parents can read about nitrous oxide for children.
Getting back to your day
When treatment is finished, the gas is switched off and you breathe oxygen for a few minutes; Becker and Rosenberg describe giving 100% oxygen at the end as conventional practice. Most people feel back to normal soon afterwards, and adults usually do not need an escort.
Advice on driving varies. One NHS patient leaflet for adult inhalation sedation, from Wirral Community Health and Care, recommends not driving, operating machinery or returning to work for two hours afterwards. Your dentist will tell you what applies to you, and it is sensible to plan a quiet hour or two after the appointment.
Questions adults ask about happy gas
Will I be asleep?
No. Nitrous oxide relaxes you while you stay awake and responsive. If you need deeper sedation, IV sedation is available at Lumi.
Will I remember the appointment?
Most people remember the visit, although it may feel shorter and less stressful than usual.
Does it replace the numbing injection?
Not usually. Nitrous oxide eases anxiety and can take the edge off discomfort, but local anaesthetic is still used for most fillings and other procedures.
If nerves have kept you away from the dentist, talk to us about what might help you feel more at ease. Free consults are available for nervous patients; see our current deals for details.
This article is general information and is not a substitute for personal dental advice. Suitability for any sedation depends on your medical history and an in person assessment.
