You can use dental treats and chews, also some types of chew toys. I give my dogs greenies, one a day under supervision, and they have access to nylabones that they love to chew on. My seven and a half boy's teeth look great, better than some one year old dogs' teeth I've seen. Some stuff is great for the teeth and bad for other parts, like the string toys or rawhide. Some people give raw bones, but they can wear down the teeth as well, and potentially cause a GI infection if you're not carefull. There's a liquid that you can put in the water, but I haven't tried it or know anyone who's tried it long term. You can also get other types of tooth brushes, ones that go on the end of your finger for example. I also saw pills and powders that are supposed to break down the tartal and keep the teeth clean, no experience with those either.