Interesting

Periodontal disease associated with red complex bacteria in dogs

Involvement of red complex bacteria in periodontal disease in dogs is similar to that observed in humans. Only the concurrent presence of T. forsythia and P. gingivalis were correlated to periodontal disease in dogs in this study.

Effects of Edible Treats Containing Ascophyllum nodosum on the Oral Health of Dogs: A Double-Blind, Randomized, Placebo-Controlled Single-Center Study

This has easily reduced the plaque on my dog's teeth.  So I decided to see if it works in humans.  

Apparently it does.

A randomized controlled clinical study of the effect of daily intake of Ascophyllum nodosum alga on calculus, plaque, and gingivitis 

I think I might try it...