Thank you for your advice
I picked up some royal canin wet food and mixed some with his dry food.... he ate most of his bowl! Yayyyy!
I actually learned by working at a vet clinic in my high school years how to scale dogs teeth. My Lola who's almost 9 lets me and my other yorkie Jax let me too. I carefully with my utensils lightly take off the plaque. Both had bright white plaque free teeth. Every Sunday was my day I'd do it along with a nail trim.
So I'll keep the teaspoon wet food going and see what he does.