They love the taste of toothpaste! I have to admit I don't brush his teeth often enough and I when I do, I just use our toothpaste, but petsmart has half an aisle devoted to this and they'd be willing to sell you the brushes and paste and everything else you need.
Here's an article I wrote a while back that explains what I do and use. ----> 42 Shiny Whites
I never use human toothpaste. The fluoride in people’s toothpaste can cause an upset stomach in dogs and sores around their mouth as they do not rinse or spit it out after brushing. Stay away from dog toothpaste with sugar in it’s ingredients. The added sugar is not really good for dogs.