we have an 18 month old. I have always been paranoid about his teeth rotting because of all the milk he drinks. This may be unfounded, but nevertheless, I'll tell you what we've done. OUr dentist friend recommended using a damp washcloth at night and just wiping off all teeth surfaces. Well, that worked until he thought it was funny to bite the @#$&! out of me, so we started giving him his own toothbrush. WE use the earth's best organic toothpaste. He loves the toothpaste, so he loves to put the toothbrush in his mouth to suck the toothpaste off. Maybe if you let your son taste the toothpaste without the brush first and then show him how to use it later that could at least get the brush in his mouth. WE let him try brushing himself first and then if he doesn't do that great of a job, we "help" him out. Sometimes its a fight, but lately, he has been opening his mouth wide for us to help him brush. I think he just gave up on the fighting and realized it wasn't that big of a deal. (or maybe he has just been too tired lately).Well, I had no intention of writing that much, but oh well. Good luck, its kind of a struggle!!