C.F.
I have a 3 1/2 year old, and this has been a struggle for me, too. I've used a few different tactics, depending on her mood and what seems to be working at the time (and her age). There have been a few times that I've had to hold her down and brush because I don't want her to get gum infections or other problems, but I rarely have to do that now. I let her brush her teeth on her own in the morning, and I brush them at night after she's had "her turn". I bought Tinkerbell toothpaste (it's pink, and she loves Tinkerbell) and a let her pick out the color of toothbrush (or character). I've used the count to 10 method- where I brush as I'm counting to ten, and when I get to ten I stop. That way she can see an end to it, and if she clamps down on the toothbrush I stop counting. Now she asks me to count! I've also used the "sugar monsters"! I told her that I had to get all the sugar monsters that were running around in her mouth. (Oh, I see one way back there- Oh, I got it! Oh, there's a pink one!) She thinks this is fun- and even calls out colors of the monsters now. It works for me- and trust me, my daughter used to absolutely refuse to open her mouth for me. A little creativity was all I needed! Good luck!