Wonder how Kim Kardashian gets her dazzling, camera-ready smile? Like everyone else: with regular visits to the dentist!

The reality star, 29, shared an, er, intimate Twitpic of herself Friday -- her mouth held open with a dental clamp, her pearly whites chomping down on a blue plastic "bit." (Despite the unglamorous shot, Kardashian does appear to be in full makeup.)

"At the dentist for a good teeth cleaning!" reads the caption. "This is serious!"

Commenters on the TwitPic page wonder if Kardashian isn't actually getting a whitening procedure versus a standard cleaning. "This is zoom whitening," insists one commenter. "I know cause I work at a dentist and this is how we do it!"