N2O Sedation Instructions

Information for Patients undergoing treatments
Under Nitrous Oxide Sedation

Nitrous oxide (N2O), commonly known as 'happy gas' or 'laughing gas', is a safe and effective sedative agent that is mixed with oxygen and inhaled through a small mask that fits over the nose to help reduce anxiety during dental treatment. It is a very safe and well-tolerated conscious sedation technique that’s widely used in dentistry around the world to help patients feel more calm and comfortable during dental procedures.

Nitrous oxide has rapid onset, is reversible, can be adjusted in various concentrations and is non-allergenic. Your child will smell a faint, sweet aroma and experience a sense of well-being and relaxation while remaining fully conscious with all natural reflexes when breathing nitrous oxide/oxygen. Your child will be capable of responding to the dentist’s questions and requests.

At the end of the dental treatment, nitrous oxide will be eliminated from the respiratory system after the dentist gives 100% oxygen for a short period of 3-5 minutes and has no lingering effects.



  • No food in the 3 hours preceding the dental appointment (occasionally, nausea or vomiting occurs when a child has a full stomach).
  • Tell the dentist about any respiratory condition that makes breathing through the nose difficult for your child, as it may limit the effectiveness of nitrous oxide.

Post-operative Instructions

  • A rubber dam will be used during the dental treatment, it may cause some swelling and discomfort of the lips after the procedure, applying some cold compress and lip balm will help.
  • As local anesthesia will be given, numbness of the mouth after the procedure is normal. Anesthesia will usually wear off after 1-2 hours. Parents need to monitor young children so that they don’t bite, suck, or play with the numb lip as these actions can cause irritations or swelling and abrasions to the tissue.
  • The effect of nitrous oxide wears off very quickly and doesn’t linger in your child’s system, but some children may feel a little tired or disoriented for a short period of time after the procedure. Parents are thus advised to monitor their children closely after the procedure. But if this happens, there is no reason for alarm; such effect should disappear after 3-4 hours.