Tuesday, August 04, 2009

Redheads' extra pain may cause fear of dentists - CNN

Despite two injections of anesthetic, Amy Anderson felt like her
dentist was jamming rods into her tooth during a root canal. She
writhed in pain as her infected tooth was hollowed with a drill, its
nerve amputated, and then sealed.

"I knew this time something was wrong. I could feel my lips," said
the Syracuse, New York, resident, who told her dentist the drugs
weren't working.

Her doctor kept assuring her she had given her a proper dose and
said: "I'm almost done."

"I was hurting so bad, I was hitting myself in the stomach," said
Anderson, a redhead. "I almost wanted to hit her."

Studies have indicated that redheads may be more sensitive to pain
and may need more anesthetics to numb them.

New research published in this month's Journal of American Dental
Association found that painful experiences at the dentist might cause
more anxiety for men and women with red hair, who were twice as
likely to avoid dental care than people with dark hair.

"Redheads are sensitive to pain," said Dr. Daniel Sessler, an
Outcomes Research Department chair at The Cleveland Clinic, in
Cleveland, Ohio, who is one of the authors.

"They require more generalized anesthesia, localized anesthesia. The
conventional doses fail. They have bad experiences at the dentist and
because of the bad experiences, they could avoid dental care."

Sessler, an anesthesiologist, began studying redheads' sensitivity to
pain after hearing chatter from colleagues.

"The persistent rumor in the anesthesia community was that redheads
were difficult to anesthetize," Sessler said. "They didn't go under,
had a lot of pain, didn't respond well to anesthesia. Urban legends
usually don't start studies, but it was such an intriguing observation."

This led to two studies. In 2004, research showed that people with
red hair need 20 percent more general anesthesia than blonds and

A 2005 study indicated that redheads are more sensitive to thermal
pain and are more resistant to the effects of local anesthesia.

Researchers believe variants of the melanocortin-1 receptor gene play
a role. This MC1R gene produces melanin, which gives skin, hair and
eyes their color.

While blond, brown and black-haired people produce melanin, those
with red hair have a mutation of this receptor. It produces a
different coloring called pheomelanin, which results in freckles,
fair skin and ginger hair. About 5 percent of whites are estimated to
have these characteristics.

While the relationship between MC1R and pain sensitivity is not
entirely understood, researchers have found MC1R receptors in the
brain and some of them are known to influence pain sensitivity.

Non-redheads can also carry a variant of the MC1R gene. In this
dental study that had 144 participants, about a quarter of the non-
redheads had variants of the MC1R gene. These people also experienced
heightened anxiety and avoided dental care compared with others who
did not have the variant.

There is no commercial test available for variations of the MC1R gene.

After Sessler and his colleagues published the first studies about
redheads and pain susceptibility, he received nearly 100 e-mails from
redheads around the country who complained of terrible experiences at
the dentist's office.

Dr. Catherine Binkley, an associate professor at the University of
Louisville's School of Dentistry, in Kentucky, also observed the same
phenomenon in her 25 years of practice.

Her redheaded patients seemed "anxious and didn't get numb. It's a
difficult experience for them," said Binkley, one of the study's

But this doesn't seem to affect all people with red hair.

"I have a [redheaded] hygienist that I have to numb up a lot more
than normal, " said Dr. Peter Vanstrom, an Atlanta, Georgia, dentist.
"She's very sensitive. I have another redheaded patient who is tough
as nails, but his father is extremely difficult to numb."

Binkley said the best tip for dentists is to "pay more attention,
evaluate everyone for dental anxiety, and ask them about previous

"If you know someone's anxious, do different things," she said. "Make
sure they're numb before you start working on them."

Patients who've had bad experiences with pain should inform their

The next phase of research is to evaluate whether more anesthesia is
needed for people with red hair and those with variants of the MCR1
gene for dental procedures.

The authors say an unpleasant incident -- much like the one Anderson
had this January -- could cause patients to postpone dental care and
exacerbate any problems they might have.

Anderson got a root canal because she dreaded the dentist after a bad
experience of getting cavity fillings. Inevitably, Anderson has to
return to her dentist to follow up on her root canal and this fills
her with apprehension.

"I have wicked dread of the dentist," she said. "I was up for two
hours in the middle of the night because of the dentist."


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