I've gone to Dental Bernal in Los Algodones four times, beginning in 2006. Among the extractions, crowns, root canal, sinus boost, I also have six implants.
No problems with any of the work.
The only people I've ever heard say anything negative about dental work in Mexico are Americans who've never gone or American dentists (except for MY American dentist).
The trick is to get references.
I wrote a journal (30 pages) during my first trip. If you want a copy, PM me or send an email to my yahoo address.
Best wishes,
SuzanneFromSeattle