I was really worried about tooth sensitivity since I've tried (and was never able to finish) about every home teeth whitening system available and always felt excruciating pain with every breath of air that passed over my teeth afterwards! But based on other reviews I gave it a shot and couldn't be happier! My teeth got 5-6 shades whiter and the process was painless. I needed a couple Advil later on that evening but the next day, no sensitivity at all! I can't stop smiling I would eat something fairly close to your appointment because it takes two hours and then you can't eat for two hours after that. I sprayed my teeth with my Waterpic before heading in and didn't have any issues. Treat yourself to a younger smile! You'll be glad you did! At least I sure am! Thank you True Teeth Whitening! I'll be back for maintenance every 6-12 months because I love these results!