It might be the protein levels in the food are too high. Phosphorous is a mineral that “tags along” with protein – i.e., the higher the protein levels in a feed, the higher the phos. will be. And if that is the case, it could be affecting the dog’s kidney function, which is a major cause of inexplicably bad teeth in young dogs.
Some dogs do naturally have a tendency to build up tartar, but there is plenty that can be done with diet to prevent it. Try a lower protein feed or one that specifically has been formulated for dental health. Several years ago, I had to put an older dog on Science Diet Oral Care, because at 2yrs old, her teeth were practically rotting out of her mouth after whelping a litter. Still don’t know the underlying cause for it, but I gave her the kibble pieces as treats, and it did help. I don’t care for the SD brand and wouldn’t recommend it, but there are certainly other brands that do make similar foods.
And just as an aside, in a bad case, the “bumpy” Nylabones and rawhides might also be of some help.
