Thanks for your question, Ginger!
I use the Veterinary Oral Health Council's guidelines. This is a third party group that evaluates the claims made by manufacturer's regarding the efficacy of their treat, water additive or dog food in helping slow the progression of dental disease.
Here is the link:
http://www.vohc.org/VOHCAcceptedProductsTable_Dogs.pdf
However, keep in mind that a annual dental cleaning under full general anesthesia is recommended in most pets!
