Flip open any magazine, turn on the television or head to the movies. You'll see them everywhere. Teeth are now preternaturally, blindingly white. Everyone, it seems, from actors on the big screen to the 19-year-old barista with the dazzling grin is fueling the $1 billion-plus-a-year whitening industry. The rule of thumb for whitening is that a person's teeth should be no brighter than the whites of their eyes. That way the focus stays on the eyes, not on the mouth.

It could give a person a complex. Calling it "bleachorexia," dentists say more and more people are coming in with unrealistic expectations for their teeth, wanting pearly whites that are several shades lighter than what's natural. In general, teeth bleaching is considered a safe procedure, but problems can arise when people stop following the directions and start thinking more is better. Over-whitening also makes it hard for dentists to match shades when doing fillings or crowns. Too much of a good thing is not always good. Although whiter teeth can give you much needed appeal, it is not everything about you.