Our dentist has a treasure box to pick from after the appointment so I made a big deal out of it. Luckily, my kids all ended up loving the dentist and always behaved when really little. When they are young, the first visits don't usually take long so that helps. You can always bribe them with swinging by the park on the way home.
I forgot to add that you don't have to phrase it as a bribe. Don't say, "Behave well and we'll go to the park." Give them expectations for the appointment. "You'll sit in the chair while the nice dentist counts your teeth and checks them out etc. Open your mouth wide and sit really still. Then we may have time to go to the park."
I can't remember if there was a reward... I DO remember him leaving and saying "Maybe there will be a clown in a box when I get home" and DH and I were all "ok, that's a weird thing to assume but whatever." And then we got home and a friend had dropped off a bday invite that was paper folded into a box shape and when you opened it - clown inside. I seriously almost shat myself.
So we're back... no cavities! I decided to take most of your advice and not play it up to much. I told them that the dentist gives brand new tooth brushes to kids who sit well in the chair, follow directions, yadda yadda. They bought it. Plus, they had a treasure chest that they got to pick something from which was cool. I didn't realize they'd have that. Thanks again!
Re: 1st visit to dentist