Tooth brushing

My son loooves brushing his teeth.

And I have been brushing his teeth long before he reached 1 year. Must have been the time he got 4 teeth already. His first brush is a yellow thing with soft rubber bristles specially designed for less-than-a-year old babies. After his first birthday, I bought him the next-stage brush with very real bristles (but still soft).

But brushing his teeth those days had been easier because he was just contented to stay still and to let me do all the brushing. I couldn't say this now.

'Course, he still loves brushing his teeth. But the thing is, he wants to do it all by himself! And he always wants me to give him a free grasp of the brush to do his thing! Fine, he knows how to hold his brush and he has somehow learned to make the brushing motions but I am just not sure if he can really clean his teeth (I do not trust him this, not yet).

I have tried getting him another brush (with real bristles too) just so he will have something to hold while I brush his teeth. But few days ago, he refused to be contented with that too. He wants the brush. That green brush that I use to brush his teeth. And it gets me oh-so frustrated (with me wanting to finish the task as fast as I can). And even more frustrated because I know it gets him frustrated, too (wanting to do it on his own).