I have a friend who needed a dental bridge. He was quoted $4,000 in the U.S., but also went to Tijuana and got it done (very nicely) for $700. The office was clean. The dentist spoke English (albeit not perfectly), and had gone to a well-known dental school in southern California. Loma Linda, I believe). If one needs extensive work done, they refer you to a motel across the border, and send a car to pick you up from the hotel and return you afterwards, until the work is complete. It is risky to take a car into Tijuana uninsured, and sometimes just difficult to find one's way around, without a knowledge of Spanish.
If anyone is interested, I can get the phone number of this dentist from my friend. He checked out a number of these dentists in Tijuana from referrals; he actually went to each office for a visual inspection, and to talk with the dentist and personnel. Respectfully, Jill