Most dentists won't let the parents go back. The thing is this, when a parent is present kids tend to look for them as the authority figure in the room. That's okay most of the time but when a dentist/doc or a teacher or some other person who "needs" to be "the" authority in some situation they can't let the parent come into their area.
They have to be able to tell the child open your mouth, bite down and yes we know it's uncomfortable, and stuff like that. But if the parent is there the kid wants the parent to make the doc stop hurting them, giving them shots, drilling, etc....so the kid can get hysterical because mom or dad is sitting there and not making the doc stop.
It's really hard for the kid to transfer trust to a stranger/doc and even a familiar face if parent is present sometimes.
It happens in dance classes at our studio. If the parents bring in kiddo and drop them off kiddo usually is perfectly behaved. If mom or dad come and stay, go watch class, the kid constantly looks to mom or dad for attention. They look to mom or dad each time the teacher says to do something. Even something as simple as bounce on your toe taps all the way across the floor to that teacher.
Our pediatric dentist in OKC, Dr. Jason Lee, is amazing. He practices at Children's Hospital and Midwest City Hospital. He puts the kids out to do their fillings and other work. For the general appointments he has all my grand kids come in at the same time, I've had as many as 3 of them back in the exam area with 3 adults at the same time. He gives each an appointment for billing. Then he assembly line exams them. They each go in a different chair for cleaning and stuff preliminary to the exam. Dr. Lee often just goes up and sits down and chats with each kid and participates in the cleaning. He plays puppets with them with the lion with huge teeth sometimes. He's the best guy ever. I can't imagine taking the kids anywhere else ever, he'll have to tell me he can't see the kids anymore because they're too old.
I am spoiled now. I can't imagine not being in the back with the kids. If we had to change dentists I don't think I'd accept it if they didn't want us back there and I would go to someone else. Well, if the kids were tweens or teens I guess I would be okay without going back.