My dentist free Zoom Whitening for all new patients so I didn't pay a single penny (normally they charge $299)! I am extremely satisfied with my results. What's my secret you ask? I used fluroide gel on my teeth each time I brushed a week prior to having my teeth whitened to help with sensitivity. Plus I took 4 advil right before the procedure began. THIS IS A MUST to prevent the "zingers" that everyone talks about. Making sure your dentist takes there time to "prepare" your teeth before turning the light on is also important. She put think sunscreen on my lips and isolated my teeth/tongue with gauze before apply the liquid around my gums. They use a light that makes that liquid on your gums turn into a rubber seal around your teeth.
I did 3 treatments of 20 minutes each with her reapplying the whitening solution to my teeth in between treatments. There are 4 green lights on top of the Zoom light that each represent 5 minutes. You can watch those light up to know how much longer you have. It is important to remain very still during the sessions but you can rest in between. I even got to watch a movie on a flat screen tv during the process which really helps keep your mind off of the contraption on your face.
This was so totally worth it!!! My teeth look fabulous and they have become even whiter since yesterday. The hard part is going without coffee or red wine for 48 hours (they say not to use colored toothpaste either-- only white. I am using the sensodyne they gave me in my goodie bag). I am going back in a few days for a followup calcuim treatment to get rid of the small white spots on my teeth.
DO IT!!!! You have nothing to lose :)