Here's my sincerest recommendation: Dental Smile clinic, Pattaya Tai and 3rd Road crossing:
https://maps.app.goo.gl/rGV7U2aVQTN1goiU8
Had some really huge problems with teeth neglected for many many years (sheer stupidity), and Dr. Oi saved it all. No attempts to talk me into unnecessary procedures (quite the opposite - I came with the attitude of "let's extract and make implants here and there" and she told me "don't be stupid, we'll save them all"), brilliant (and I mean it) work - 11 crowns, numerous canal cleanings and small repairs, and - my mouth feels great years and years since.
All for nearly half the price of Bangkok Hospital Pattaya.