Yay! Rocky's out of the anesthesia and alert. The vet had to pull the one tooth, and discovered that others had been "resorbed". As explained to me, this means that Rocky's immune system, for whatever reason, "went after" some of his teeth and weakened them to the point that they broke off. The gums closed over the base of the teeth, and they calcified into part of the jaw. I had certainly never ever heard of this before, but the vet assured me that it was quite common in older cats. Live and learn!
I will call the vet's office in a little while to see if Rocky can come home tonight. He has to go back in a couple of weeks to make sure he is continuing to gain weight. Here's hoping!