The dental work in both countries is about the same, you have very good, good and not so good, the difference in price is that the US dentist has to pay exorbitant prices for insurance, malpractice insurance and then all of the EPA hazardous material handling fees, that translate to expensive procedures.
The school of dentistry in Mexico is recognized in the USA and Europe and many of the Mexican dentists study in the US and Europe, the art of dentistry has been practiced since before the Spaniards colonized the continent, if you doubt this look up dentistry in the Aztec culture, the skulls with the front teeth with inlayed obsidian stone.
navegator