If you get a problem with plaque, plaque off seems to be recommended time and time again. I was talking to someone with a very old rottie at a dog show the other week, he was a rescue and his teeth were awful when he got him. He used plaque off, and said it took a few months to really start seeing results, but his teeth were lovely (I had a good look!).
My latest rescue, Dexter, has hideous teeth, I'm going to start him on plaque off soon, he really needs a dental at the vets but because he is a very fearful dog and has a needle phobia they don't want to stress him out that much for the time being. He would have to be heavily sedated before they could even get near him
I've got some raw duck necks ready for him, but as he is a resource guarder, it's going to need some serious management to let him and my other dog both have a bone without ructions!