I don't understand, I brush them twice or thrice a day, very carefully and very well. I don't smoke, and I use the toothpaste my dentist recommends. I've tried a few "Teeth Whitening" toothpastes, but they didn't seem to make a difference.

My dentist said I'm over-brushing and it's scraping away the enamel layer, showing the more yellowish dentin layer beneath. However, I get the feeling she says that just to settle me with an answer- one that may or may not apply to me.

It's really disheartening when people tell me to brush my teeth. Can anyone tell me what's going on?