Fortunately, my daughter had a friend who had to have fillings done at 3. She didn't want to go to the dentist to "get drilled."
When she did refuse, as they all do (power/control),I explained that this was one of those things that had to be done whether she liked it or not, so I was going to brush her teeth. I brushed them through the tightly squeezed lips and then the cry, which opened the mouth. It was painful for me to do, but she needed those teeth brushed and nothing else worked. When she says she's not going to brush now, I say, "Then I'll have to brush" and I puck up the toothbrush. Usually that is all I have to do. Occasionally, she pushed it farther and I have to put the toothpaste on it. Last week, I had to brush lips and the mouth opened. It was about control.
Stephanie