Not sure about the US, but we have a voluntary accreditation service for dentists here. So only those dentists who are willing to undergo audit actually achieve accreditation of this type.
It's a good way to find out how serious they are about their practice. No accreditatation means they either failed or they couldn't be bothered.
I would prefer those who were willing to let someone audit their practice fix my teeth.
Not sure if there are any such accreditation processes in the US, but the dentists association would know.
Cheers
Mick