Hilary Duff has undergone extensive dental work because she keeps chipping her teeth on microphones during performances.

The A CINDERELLA STORY star, whose mega-watt smile has attracted intense speculation, resorted to having veneers after damaging her enamels during energetic stage shows.

Duff explains, "My teeth aren't the strongest, and I kept chipping them on the microphone.

"One show, I literally spit half of my two front teeth out.

"Why is it people's business?"