I use Healthy Smile Dental Clinic in Silom Complex in Bangkok. The dentist speaks good, if hesitant English. A simple tooth cleaning is about $15US. I don't recall the exact prices now, but for everything from having a wisdom tooth out to a ceramic crown (both procedures I've had done there), their prices were considerably lower than the fancier clinics in Bangkok (and a tiny fraction of US prices). They serve locals and foreigners and have another branch across town for more involved procedures. As other people have pointed out, the savings will more than pay for your vacation.

Bangkok is also the destination for many expats throughout Asia who need medical care or just a simple check-up. Many hospitals, like Bumrungrad or BNH, offer services that are as modern and efficient as anything you'd find in Europe or North America. I've used the former and both my father and step-mother have been hospitalized at the latter, with no complaints whatsoever about the care and attention provided.