It was a horrible experience! The process took 4 hours long, and after the treatment, yes, my teeth were white for about 1 week only, but the pain was unbearable. I went back to the dentist and complained. She injected local anesthesia around my gums to alleviate some of the pain, but that didn't do a thing! I had severe blistering. But the worst thing, is that a week later, my teeth were all cracked. Now the dentist is saying I may lose all my teeth!