Nitrous Oxide Relaxation Gas:

Nitrous oxide (also called "laughing gas") is a safe and effective
way to reduce anxiety during a dental procedure. It does not numb
the teeth, however, and anesthetic will still be used. It does produce
a pleasant, calming effect which people describe as "happy,"
"unconcerned" and "disconnected" from what is happening.
Nitrous oxide is inhaled through a small mask that covers the nose.
It takes just a few minutes to take effect, and the effects wear
off soon after the mask is removed. You can safely drive after
an appointment where the gas was used.