A variant of the melanocortin-1 receptor gene in redheads causes a resistance to subcutaneous local anesthetics, which researchers say could cause these patients to experience greater fear and anxiety over dental procedures.

In a survey of 144 subjects between 18 and 41 years old, researchers discovered 65 of the 67 redheaded participants carried MC1R gene variants, as compared to 20 of the 77 dark-haired participants. Those who carried the gene variant were twice as likely to avoid dental care, regardless of general trait anxiety and sex, say the researchers. Their findings appear in the July 2009 issue of the Journal of the American Dental Association.

"Dentists should evaluate all patients, but especially those with naturally red hair, for dental care-related anxiety and use appropriate modalities to manage the patients??? anxiety," the researchers conclude.

Anesthesiologist Daniel I. Sessler, MD, chairman of the department of outcomes research at the Cleveland (Ohio) Clinic, told the New York Times, "Because they???re resistant, many redheads have had bad (dental) experiences. If they go to the dentist or have a cut sutured, they???ll need more local anesthetic than other people." He says redheads should notify their physicians about the high probability they're resistant to painkillers before undergoing procedures requiring an anesthetic.

—Daniel Cook