my girls also doesn't want to brush teeth.. then, we (i and my c6) need to do the show in front of her.. e.g. i brush c6 teeth, c6 brush mine, and i brush my daughter <-- sometimes she is ok.. but sometimes not.
Sometimes, I also need to use my finger to pretend the toothbrush and put the toothpaste on. THen, to brush her teeth. I don't know my daughter is afraid of toothbrush or toothpaste,, need to to a long time to train her...