Toddler teeth

Right now, the most challenging thing with Penny is brushing her teeth. The pediatrician said that we have to try to brush her molars (she has 3 and a half), but she won't open her mouth enough for me to get to them with the toothbrush. So, I use a finger toothbrush and she bites my finger...really hard! It is a struggle every time. The next strategy we will try is a reward system. You could call it positive reinforcement or a bribe. whatever works, right?