What is the role of topical benzocaine before LA injection?

• A. To provide surface numbing and reduce pain of needle insertion
• B. To numb deeper tissues beyond mucosa
• C. To sterilize the skin
• D. To prevent bleeding at the injection site

Answer: (A)

Topical benzocaine is used to dampen pain sensation at the surface where the needle will enter. It works by numbing the superficial nerve endings in the mucosa, blocking sodium channels and reducing the transmission of pain signals right at the site of contact. Because it stays on the surface and doesn’t penetrate deeper tissues, its numbing effect is limited to the mucosa and won’t affect deeper tissues where the injection will occur. It has no sterilizing or bleeding-prevention properties, so it won’t sterilize skin or stop bleeding at the injection site. Applied correctly, it provides quick, short-lived surface anesthesia to make needle insertion more comfortable.