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."