I think that by the time they are 3 years old they should have been to a pediatric dentist for a check up. They most likely won't do X-rays and poke around in their mouthes too much until then.
A pediatric dentist is a dentist who specialized in baby teeth and young children's teeth. They are NOT a family dentist who just does baby teeth.
My BFF has a daughter who is about the same age as our K. Her daughter got a cavity in a front tooth. She didn't want to go 125 miles away to our pediatric dentist so she took her to her family dentist. He gave the girl shots in her mouth, drilled, filled, sent her on her way. The filling fell out, went again, did it over again, sent her on her way, it fell out, he pulled that tooth because he didn't want to deal with it again. After 2 years of no front tooth she in finally getting an adult tooth in the spot.
K fell at 3 years old and broke off her front tooth. She had cavities in the back also. Bad teeth run in our family on both sides. The pediatric dentist put K to sleep in the hospital out patient surgery, filled the bad teeth, drilled and capped the front tooth, and NOTHING every fell out or had to be redone. He knew what he was doing, he does this type work every day.
It is well worth the effort of going to a pediatric dentist.