The significance of needle gauge in dental injections.

Dentists administer injections on a routine basis with minimal consideration given to the needle used. Patients often associate pain with injections. Gauge is the measuring standard used in needle width classification. Despite the institution of American National Standards Institute/American Dental Association (ANSI/ADA) specification no. 54, variables still exist in classification of needles. The authors describe inside and outside diameters of the needle, ability to aspirate, and effect of needle size on pain, and offer suggestions for needle selection.