cat with renal disease suddenly lost most of his teeth

He's 9 and was tentatively diagnosed with renal disease about a month and a half ago. His blood levels were normal, but he has small kidneys, had blood in his urine, and has been steadily losing weight and my vet felt that was enough for a diagnosis. He's currently on Hills K/D kibble that we soak and heat and give to him mushed up. He wont touch the tinned type. He was in to the vet three weeks ago and she pointed out a tooth that had some redness around it, but all others looked fine. The next appointment a week later he had lost the tooth with swelling and several small ones up front. We had to go back again last week and another tooth was gone. That last appointment was on the 13th. Today he wasn't eating and I checked his mouth and all of his back teeth are gone, both the tops and bottoms. Two of his front canines are greyish. The vet says tooth loss in elderly cats is normal. But, so many so fast?  His gums are naturally dark colored, but seem a little pale. We called the vet to ask about bringing him in, but they said to call back tomorrow if he doesn't eat.

I personally have never heard of dental disease going this fast.  Both of my kitties have dental issues, one very prone to gingivitis the other has had teeth removed for FORL.  They are 11, one has had 5 teeth pulled the other one 2, and their teeth didn't go bad this fast.  I would be concerned as to the cause.  

I, too, think this could be a cause for concern.  I have a 14 and a half year old kidney cat, and she has ALL her teeth!  She has never had any teeth issues in her life.  I have had other kidney cats, and only one ever had any dental issues, and that was BEFORE he had kidney problems.  (he had to have 4 teeth pulled years before he developed kidney disease, and after that, just the occasional cleaning).

My guess is, something else is going on. 

Sorry I haven't responded, we had to discontinue our internet to try to pay for more vet care. But, I'm back temporarily.

All in all he lost most of his teeth. He has two canines in the very front left, there is one molar in the back that I thought was gone, but is still hanging on, and a spattering of his tiny front teeth. He still wasn't eating and about two weeks ago he went in for a body xray where the only thing noted was a thickening of his intestinal lining and typical calcifying of some cartilage of his ribs and an old injury in his hip that resulted in part of the ball of one femur being absorbed into his body. She checked his mouth again and everything looked fine to her and she just shrugged off the tooth loss. He didn't have a fever and there was no noted swelling.

Yesterday we finally had enough to pay for an ultrasound and the results of that were swollen lymph nodes in his stomach and odd intestine movement. I don't know what the technical name for the movement is called, my boyfriend took the call, and couldn't remember and the vet didn't call me back before closing yesterday. Anyway, they scheduled exploratory surgery for this morning, in about five hours.