Watch out for most of the water additives - a few contain xyloitil, which is toxic to dogs. They claim it's safe in small amounts but I don't like them.
The only water additive proven to work and approved by the VOHC is HealthyMouth - they have a gel and a water additive. Both have had clinical trials.
I like Petzlife, even though it has some alchohol in it as an ingredient, I don't feel it's enough to harm much of anything.
I also use CET toothpaste and CET chews. I don't really like Greenies, Dentastix, etc. And yup, bully sticks, Himalayan chews, etc, will help keep teeth clean.
