What a freaking day!! Yesterday when I brushed my teeth one side was acutely sensitive. I called the dentist and said please fit me in I have a cavity. Low and behold what I have is not a cavity. He said that all the years of using tooth whiteners have made my enamel weak so right where the tooth meets the gum is pourous and is essentially exposing the nerve which makes it very sensitive. The only solution is to put a kind of seal at the base of the tooth and do daily applications of flouride directly on that area. The Dentist said it will take a long time to feel better and I will have to replace seal every 6 months. What the fuck!!!