What Does Dental Plaque Look Like What Is The Hard Yellowish Hard Object Surrounding The Base Of My Yorkie's Tooth?

What is the hard yellowish hard object surrounding the base of my Yorkie's tooth? - what does dental plaque look like

I inherited a yorkshire 6 years. It seems that something in the bones and broke into pieces and glued a small piece of his tooth. I tried to gently, but he is busy. Now I think I see another molar on the back! Your mouth smells terrible, and it was treated for a severe infection in the mouth. I did not notice these things until recently. The veterinarian has obviously not seen anything good when it was tested. It is due next week, dental, and of course we then have an answer, but until then, everyone knows if this could be the motherboard?