Teeth straightening and whitening?

Hi, i've had my front top two teeth vanneered because i was premature when born and the enamel on my teeth was weak and my teeth kept chipping. i got them done for free on nhs as was only 17 at time, however i now want one of my other teeth done as it sticks out slightly. I dont know whther to get anythin done to my bottom teeth also, they have been worn down as dont have much enamel on but dont look bad, just little. what should i do. How expensive And is it painfull, as all i had done last time was vanneers.Really appreciate your advice. Thankyou x
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its not painful but its very expensive. about 1000 dollars a tooth
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