The Duchess had undergone some treatment for her pearly whites, and this explains her slightly crooked, 'un-American' smile.

According to reports, Kate Middleton had to undergo a special treatment to alter her smile to make it look 'un-American.' Dentist Didier Fillion, the famous doctor behind the altercation, used a hidden brace to crook Kate's perfect teeth - resulting to an "imperfect smile" that makes her seem "perfect."

"He did some little micro-rotations on Kate, that's why they look so good - because they are not ­perfectly aligned" said Bernard Touati, a friend of Fillion and a dentist himself, to The Mirror.

As much as it is a paradox, many are wondering why this procedure had to be done. It is because Kate used to have perfectly aligned, straight teeth, giving the impression that it was not natural. This dental procedure is called "French Polishing," giving off a slightly-crooked, more European smile.

In different parts of the world, not many women would jump at the opportunity to purposely make a smile look "imperfect."

"The problem in the United States is they have very artificial vision. But what we like is a natural healthy smile, but not artificial." added Touati in the same report.

Notice the Duchess' smile in these photos and see the "un-American" smile for yourself.

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