What can i do to convince my 17 month old to brush his teeth?

Not much: A 17 month old is too young to brush his teeth by himself. He simply doesn't have the motor coordination to handle such a task. Sure, he can put the toothbrush in his mouth and move it around, but is he really brushing his teeth? Probably not. The best thing to do is to brush his teeth for him. Do it gently, so that he does not become scared of it.

Who's the boss?: At 17 months i don't think there is much thought as to who's the boss. Your child may be difficult but you can try to make it a game or trade off something that the kid likes for brushing. Pick your battles but this one shouldn't cause too much greif. Use your imagination.