I did Zoom whitening at the Dentist office years ago. The process was very uncomfortable and I wasn't thrilled with the results, made my teeth chalky white and had to use additional stuff to even out the color. Made my teeth incredibly sensitive for days, def wouldn't do again. As is my teeth are pretty white, but after doing invisible teeth alignment it wore down my front fillings. I kept getting stains in between the area of my tooth and filling. I was hesitant to try this as I have front fillings, as well as the concern for teeth sensitivity. Seeing the reviews figured I'd give Snow a try as the price wasn't horrible. Certainly glad I did, I couldn't be happier with the results! I noticed an improvement after 3 days and now after 1 week my teeth are beautiful white, got rid of the stains and the whitening is very even, even with my fillings. I've experienced zero sensitivity issues using it every day. I started with 10 minutes every evening and have been doing 15 minutes past few days. I'm looking forward to continue seeing the results in the upcoming weeks! Excellent product highly recommended!