WARNING!!
I friend of mine popped some toothpaste on a spot before going to bed after I suggested this to her, she happily went to sleep, the next mroning she had not only the spot but the whitening agent in her toothpaste had bleached her face and left her skin really really dry and flaky!! She decided to go to work the next day with excess colourfull eyeshadow and a hat to divert the attention away.
I would normally say toothpast is fantastic, but don't use the advance whitening stuff!!