Uh oh -- it's the story that dentists around the world are cringing at. Apparently, flossing can cause... tooth chipping?!

At least that's what happened to Twilight's Rob Pattinson, according to his Eclipse costar Bryce Dallas Howard!

"He told me this story that made me crack up," she said. "He was like, 'Oh, I have to go to the dentist.' And I was like, 'Oh no, what happened? Just a check-up?' And he was like, 'No, I chipped a tooth.' And I was like, 'How?' And he was like, 'Flossing.' Who does that?"

Ha -- who else but Rob can make headlines with his lack of hair-washing and excess of flossing, right? Gotta love him!

Photo: Courtesy of Summit Entertainment