At what age do you need to start visiting a kids dentist?

You can take the kid to a dentist around his first birthday. It would be a good time to get the kid used to seeing a dentist setup, the chair and also getting yourself educated on how to care for child's teeth. For more details refer http://www.webmd.com/oral-health/features/when-should-i-take-my-child-to-the-dentist