I use Proden Plaqueoff - this stuff really works over time - BUT should not be used if the hound has thyroid issues.
http://www.entirelypets.com/plaqueoff180.html?gclid=CNu0vNLj76ACFQadnAodAk5QDQ
Also, Wendy gets raw, meaty bones 2-3 times a week. These include - lamb shanks, turkey necks, beef marrow and knuckle bones, turkey wings - whatever is available and the price is right. Of course, she gets her "spa day" once a week when we do grooming -nails,ears,teeth.
I brush her teeth with doggie toothpaste and I use a piece of old hosiery instead of a toothbrush to gently scrub her teeth and gums.