Dental Allergies

Most people know when they're allergic to certain metals -- like those in jewelry.

But those same allergies could be causing a much more severe reaction inside their mouth. And it causes problems that often go undiagnosed.

A few years ago Cate Bennett couldn't relax when eating out. Severe dental problems led to an infection, crowns on her four front teeth, and one mortifying moment at lunch with a friend.

"The first bite I took of the salad, I watched my crown fall out in the salad bowl," Bennett said. "I was so embarrassed."

Turns out, Bennett's allergy to metals in jewelry also made her allergic to the metal crowns in her mouth.

"I had inflamed gums," she said "I had a great deal of sensitivity and When Dr. Joseph Kravitz saw Bennett's grey and purple gums and the holes where her gum tissue was pulling away from her teeth, he immediately recognized the problem.

"For 80 percent of the people that have an allergy on their skin, they also have a problem inside their mouth," said Kravitz, a prosthodontist at the Washington Center for Image Dentistry in Bethesda, Md.

Studies show up to 16 percent of women and six percent of men are allergic to metal that's found in onlays, crowns, and dentures.

"It gets red, it gets swollen, it gets itchy, and you have a strong metallic taste," Kravitz said.

The solution is simple -- replace metal crowns -- seen here on the far right with all ceramic ones -- seen next to it. And the allergies usually fade within a day.

"In 90 minutes my gum went from sort-of a grayish purple to a healthy pink,' Bennett said.

And now Bennett eats out with confidence.

"I'm so happy with it," she said. "I actually feel like my smile is one of my best features."

The most common allergy is to nickel, but other metals like gold and chromium can also cause problems -- and these allergies can develop these over time.