I switched my ferrets to raw this year and have never seen such a change in teeth. Bode had some solid stuff that would not come off of his molars and a week with bones and it was GONE. His teeth are perfect, shiny white now. He is a two year old ferret and has teeth like a baby.
My other ferret has a lot of health issues and on raw his teeth are also sparkling clean. Less of a big deal since he is less than a year old still but I am proud.
These are bone in meals. Ferrets eat bones, it's kind of scary. But dang they have nice teeth. I don't know if dogs can eat small raw bones or not, I haven't done lots of research on that front yet. My ferrets can crunch clean through a drumstick in one bite. I bet adding bones, if they can eat them, would really keep teeth nice.