I have done different things with Alex to get him to brush his teeth.  We started brushing before he even had teeth, just to get him used to the pattern and the feel.

Now I help him brush his teeth after meals (if we are home) but at least in the morning and before bed.   By help him I mean I do it for him enough to sing a song or two just to make sure they are getting cleaned.  After I do that, I let him brush them too, while I am brushing my own teeth.

I like this pattern because he is getting a since of independance, but they are still getting cleaned.  Also, he likes to sing songs and to brush our teeth together.

If you are having a hard time with your toddler wanting to brush their teeth try this out and see how it works for you.