We've had a really hard time with this too! The American Academy of Pediatric Dentists recommends kids go as soon as they get they're first tooth, but, our dental plan doesn't even have any pediatric dentists and adult dentists don't seem to know about the AAPD recommendations because they kind of laugh and say, "kids aren't usually really seen until they're at least three). Maybe we should all just go to school and become pediatric dentists!
:-)
We finally showed our dentist an article and I explained that I'm really just looking for my child to develop a good relationship with a dentist and start to get the idea of what going to the dentist is all about and how important clean teeth are and then he was more on my side and willing to give her a look. (Especially when I showed him that if you ask, "what does a doggy say"? she pants and opens her mouth). Obviously a pediatric dentist is preferable but if you can't find one, educating a regular dentist probably doesn't hurt anyway. If your child has some more specific need where a specialist is required your regular dentist should be able to refer you to one.
Good Luck
R.