I think its a great idea. I read in a Yorkie book that a lot of older toy dogs die from tooth decay problems because their mouths are so small so teeth are more crowded than in a big dog. Also, the interaction is good for social health too. Being able to touch and brush your dogs teeth is a great thing! If you ever need to give your dog medicine, you will be glad that you did that!
I wish I would have started brushing Milo's teeth when he was a puppy, We are just starting to brush his teeth and he HATES it. And when we had to give him medicine, because we hadn't played with his teeth and mouth so he was like "What the hell are you doin mom" and he wasn't havn' it at all!