I was considering flying into Bangkok and out of Chiangmai on my next trip in April. After reading this, I'll reverse the process and spend a day or two in Bangkok at the end of my trip. I'll have to find a good Dentist in CM to replace a lower tooth that got knocked out last March in an industrial accident (part of board kicked off of miter box saw into face). Unless anyone can recommend one, I'll check the CM forum on ThaiVisa.
If you're going to have it done in Bangkok, I used Dental Design Clinic some years ago, after someone else had previously recommended them to me. They did an OUTSTANDING job for me! I recommended them to a friend of mine a while back, and they did an outstanding job for him, too!
They used to be on Asoke, moved recently, I think they're on Suk Soi 19 now. Check Facebook, or do a web search.