Teeth brushing?!

Annabel • "For this child I have prayed..." 🛐✝

My son is 17 months old. Still drinks from a bottle but also drinks from a straw. He hates supply cups I'm afraid. Still has a bottle at night. Trying to brush his teeth is a nightmare. Not because he doesn't want me to, but because he wants to do it himself with the brush. Should I just use a finger brush to start with? He will probably bite me lol but I'm not sure how to get his teeth brushed. He only has 7 teeth and he has 2 more coming in right now. How do i get him to brush his teeth?