Who would want a smile that looks like this?
Well, you'd have to assume pretty much nobody. Unless it's just temporary and you're getting paid.
During this study, only one side received whitening treatment.
What you're looking at in the picture to the left is the type of results participants in the best tooth-whitening studies end up with.
We use the word "best" not because of the level of whitening results but because of the research's design. This type of evaluation is called a split-arch study.
All whitening research should be set up this way.
Surprisingly enough, the first published account of research using this method didn't take place until 2003. And it and further studies like it were instrumental in demonstrating that the use of a bleaching light servers little purpose in any tooth whitening process. You can read the whole story here.