I have know several people, mostly self employed who go to Mexico for their dental work and most have been real happy. I mentioned this option to a couple of different dentist here in the states, with two different responses; the one dentist didn't liked the idea saying, "people come back from down there after surgeries having objects left in them", while a different dentist from Comfort Dental told me she recommends the options for the frugal minded stating, have your regular checkups and maintenance done locally, and have things like root canals, crowns and bridges done in Mexico.
I have had major work done the last couple of times overseas, along with several other family members. I figure a savings that could be applied as a nice down payment on my next Newell.