i dont know, but b-cuz i had a small gap in front teeth, i got crowns (DONT DO THAT!!!!) unless needed!...if you ever got your nails done...it is like that ,i heard, they file the front only, then put on the venneer, i wouldn't do it unless i had to!
b-cuz it only lasts 10-20 yrs...you gotta have $$$$ for upkeep, or you will have no teeth!!!! i wish i got braces!