There is no recognized specialty of cosmetic dentistry (though there is
an academy) and right now any dentist may call him/herself a "cosmetic"
dentist.  A prosthodontist must have successfully completed a graduate
or postgraduate program qualifying for the board exam.
    You want someone who not only does pretty work and uses a top lab, but
can communicate with you and the lab to make you happy.  If you have a
dentist you trust, that would be a good place to start.  Whether you get
referred out or not, you will go with guidance and an understanding of
why you're going where you are.

Steve