Should i get laughing gas or a shot to relieve pain for a cavity filling?

Shot: Local anesthetic shot is preferable but if you are anxious type gas may work better before injecting local.

A shot: Laughing gas, also known as nitrous oxide, is an inhaled medication that is a slight relaxant, for most people it will do nothing for pain. It is mainly used to reduce anxiety. Local anesthetic, commonly referred to as novocaine, is used to deaden the nerves associated with the tooth so that you don't feel pain during the procedure.