Anesthesia has traditionally meant the condition of having sensation (including the feeling of pain) blocked or temporarily taken away. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience. The word was coined by Oliver Wendell Holmes, Sr. in 1846. Another definition is a “reversible lack of awareness”, whether this is a total lack of awareness (general anesthesia) or a lack of awareness of a part of the body (local anesthesia).
For the most part, in general dentistry, local anesthesia is used to block sensation to a limited area, allowing that area to be treated without sensation. For most dental care local anesthesia is administered by an injection, using a very small needle. Some minor soft tissue procedures can be performed without an injection, using a topical anesthetic gel to achieve comfort.