[unhappysmiler]

Please help! Im 18 years of age and thanks to my old dentist have a blotched smile.
Up until the age of 13 I never even had tooth decay but all that changed when I changed dentist. My new dentist managed over a two year period to find enough cause to put fillings in all of my pre-molars, molars (on my lower and upper jaws) and the 2nd premolar on my lower jaw.
Thankfully though, these weren't too noticeable but I've since got braces and what with the repositioning on my teeth, the filled 2nd premolar on my lower jaw with its ugly silver filling is very noticeable.
Also try as I might, and I do with frequent flossing etc I cannot help the fact that recently black spots have appeared on my two 1st premolars on my lower jaw.
My (new) dentist says none of this is a major concern and that my teeth are all healthy and well cared for but I can't help feeling paranoid!
Is there any procedure that could rectify these issues and if so would it be very expensive (as I'm only a student and my family aren't very well off)?
Many thanks.