Greenies
       Greenies are a whole new thing. Big green dog biscuits, shaped vaguely like a toothbrush, Greenies are nutritionally a huge improvement over pig ears and the other things we let out dogs chew on. It takes a lot of serious chewing to work through a Greenie and they clean the teeth remarkably well. In an independent study, dogs on a normal diet plus one Greenie a day developed only an eighth as much tartar as dogs on a normal diet alone.

       The really amazing thing about Greenies is how much dogs like them. In an independent study, when offered a choice between greenies and rawhide chews, every single dog chose Greenies over rawhide chews. Dogs just love the darn things. The label lists a "natural flavor enhancer", which is probably what makes them taste so good, but nobody I've asked will admit to knowing what it is. Greenies get their color from chlorophyll, which neutralizes odors. Assuming that your dog's mouth is fundamentally healthy, Greenies will actually make his breath smell nice. Imagine that.