I had Zoom whitening done. My results were instant and I was very happy with the level of whitening achieved. It was a bit painful that night and have ulcers on top and bottom gums. But after 48 hours, my teeth have started to look dull and have a yellow tinge on them again. I have only had white foods to eat or drink at this time. I'm very disappointed.
I want to know why this is happening. Any advice?