"I assumed everybody brushed their teeth all the time," says Dr. Bill Dorfman
Credit: Gregg DeGuire/PictureGroup

Jessica Simpson s pearly-white smile just got a little tainted.

Last week, while appearing on The Ellen DeGeneres Show, the singer revealed that she brushes her teeth only about three times a week.

“My teeth are so white and I don’t like them to feel too slippery, but I do use Listerine and I do floss everyday,” she told DeGeneres. “But I don t brush them everyday. I ll use a shirt or something … I know it’s gross, but I always have fresh breath.”

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Simpson s dentist, Dr. Bill Dorfman, who appeared on an episode of Simpson s previous reality show Newlyweds: Nick and Jessica and maintains a practice in Los Angeles, says he’s surprised and concerned about her brushing habits.

“I was kind of shocked. I assumed everybody brushed their teeth all the time,” he tells PEOPLE. “People pay us a lot of money for that slippery feeling. It s kind of the best part.”

But this wasn’t the first time Simpson has talked about her lack of brushing. In March, the singer told a group of people a similar story at the “iheartradio presents an Evening with Jessica Simpson” in New York.

“Find me when I’m 60 and [my teeth] will probably be all out, but I literally have these strong powerful teeth that don t need to be brushed,” Simpson told the audience.

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Dorfman says people should be brushing and flossing after every meal, or it can cause anything from inflamed gums to heart disease.

“It’s great that she s flossing all the time, but you have to brush too,” Dorfman recommends. “What goes on in your mouth really affects your whole body.”