
Definitely a large raw knuckle bone is the best teeth cleaner. I adopted a really old dog some years back, and his teeth were filthy and covered in tartar. My vet commented on it when I took him in for a check up. There was no question of a dental because of his age.
He was treated to a large marrowbone regularly, as were my other dogs and I thought nothing of it/ When I took him back to the vets for something else and he looked in his mouth, he couldn't believe how clean his teeth were. All the tartar had gone and his gums were looking healthy. He never had a days problem with his teeth.
Plaque off is good for some dogs too. My youngest GSD, despite having bones can get dirty teeth, and I just use Plaque off for a couple of weeks, and they are sparkling white again.