I purchased a teeth bleaching kit 2 weeks ago and was most satisfied with my purchase and would recomend this to any smoker or caffine drinker.
You are required to use for 10 consecutive days taking about 15 minutes of your day. I didnt notice an improvement for the first few days but after day four I could see the improvement, and after finishing the treatment my teeth are now a nice pearly white.
I have not suffered any kind of side affects althought when I used a little too much gel my gums became a bit sensitive but once a rinsed my mouth out there was no further problems. I swallowed a bit one time and puked it tastes that bad but a small price to pay for white teeth.