laminate veneer – thin material, generally tooth-colored, used to cover the front of a healthy tooth to restore the appearance from discoloration, damage, misalignment, or other such cosmetic issue

laughing gas – common term used for nitrous oxide, an odorless gas that produces a mild sedative effect when inhaled

lesion – tissue injury, generally due to trauma, infection, or illness

ligation – process of attaching archwire to braces in orthodontic treatment

ligature – thin wire used to hold archwire in the bracket in orthodontic treatment

lingual – refers to area or surface on or around the tongue, opposite of facial

lip bumper – archwire attached to a piece of molded plastic, holds back molars of lower jaw to provide more space for the other teeth

local anesthesia – medication used to block nerve impulses to provide partial or complete elimination of pain during treatment