Nitrous Oxide, also known as laughing gas, is a very mild form of sedation used in dentistry. If you are just a little nervous about your treatments, this may be the best form of sedation for you. Nitrous Oxide has been used by dentists for many, many years and is still the most common form of dental sedation used today.
The gas, known as N2O, is mixed with oxygen to create an inhaled sedative administered by your dentist through a mask worn over the nose. As you inhale the gas, you will be asked to breath normally through your nose. So long as the mask is worn you will feel the effects of the gas. The sedation will wear off immediately after the mask is removed, so there are no long lasting effects.
As this is a mild form of sedation not intended to put you to sleep, you will remain able to hear and communicate with your dentist during the procedure. Although ultimately feeling comfortable and free from dental pain, you may experience a tingling in your arms and legs or perhaps even a heavy feeling in them. This, plus some light-headedness is perfectly normal and will wear off upon removing the mask.