It's probably called Periodontal Disease. At least that's what it is called in humans. I wouldn't imagine it would be called anything different in cats. I used to work for a dentist and I saw a lot of nasty stuff there. There is no cure for this disease...that's probably why they are pulling all of his teeth. With humans you go thru a series of cleanings to control the disease (not a normal teeth cleaning either) that is painful and then regular visits after to make sure that the disease is controlled.

I hope that Spike is better real soon.