It made my front teeth less yellow, but not white by far. It did absolutely nothing for side teeth cause they are still as yellow as can be.
Oh and the so called Zingers hurt like hell. Mine came in waves about every 10-30 seconds or so and it comes from all your teeth. Dentist had to prescribe Vicodin extra strength for the pain and I was popping them like candy which helped a lot.
If you get this done I would advise getting the doctor to give you a prescription before hand and take 2 before the procedure and continue to take them for at least 24 hours to avoid what a lot of us went through.
On a side note since I have had this done my teeth seem to be permanently extra sensitive to everything and they where not like this before and it's been 6 months now since it was done.
I would not recommend ZOOM Whitening to anyone cause it's just not worth it for the money. If they are going to use the Word WHITENING then your teeth better be WHITE when they are done, far as I am concerned it's false advertising and a rip off. Me and wife spent a total of $700 for nothing.