Review (2/5): Didn't work for us
I used this exactly as the instructions said and after 10 days, there was absolutely no difference in my teeth. I took before and after pictures to monitor the progress, and the two are exactly the same. My teenage daughter then tried it (after sanitizing, of course) and she had the same result as I did. Maybe it's genetics, or maybe our teeth just didn't take to the product, but we were very disappointed at the results. That said, it was easy to use and incorporate into a daily routine, and there was no sensitivity or bad aftertaste whatsoever.