I've been using Healthy Mouth for over a year now and so far my vet says that all their teeth look really good. I took Riley to a specialty vet dentist who recommended it (along with brushing of course) after she pulled a few of Riley's teeth. I don't know if that was a side effect from her daily steroid use or what. I got the same size jug you got and even filling two bowls of water daily for four dogs, it still lasts forever.
The veterinary dentist also recommended some soft rawhide chews for dogs which also reduce prevent tartar,plaque and gingivitis and have the VOHC seal. They're sold by Tartar Shield and my dogs love them.
I started brushing Fletcher's teeth the day after I brought him home at 12 weeks. I use Petzlife, a regular tooth brush and the finger toothbrushes. Fletcher too thinks it a treat and a game. I'll admit some nights his teeth are better brushed than others, but I still think its the best way to go. Mr. Monster also likes to "help" I have learned to keep a little stock of his own tooth brushes in the house because he is always putting Fletcher's toothpaste in HIS tooth brush!!!! So while I'm brushing Fletcher teeth his favorite playmate is waving around an Elmo tooth brush with the "treat" on it too. We laugh a lot but it gets done.