Liquid dental additives?

I use pet kiss dental liquid in my cats drinking water fountain, does anyone try this or can you recommend something similar? thanks

Personally, I don't think liquid additives do anything. A cat isn't going to drink enough water from a bowl or fountain for the additive to have any effect. It's better to brush the cat's teeth to remove food particles and plaque or give a large dental treat like the CET ones.

We asked our vet about this recently and she said the only additive she knows of that is backed up by research is Healthy Mouth.
http://www.healthymouth.com/Articles.asp?ID=253

This is in addition to regular brushing to remove the loosened plaque.