I'd be surprised if the teeth went from being no problem to a serious
health concern that quick.

The biggest issue I've seen is build up of plaque on the teeth, and
gum disease.

Both of these can be seen by looking at the sides of the teeth.

Ideally, a thorough dental cleaning/scraping would tell you more, but
often times that involves sedating the ferret.

If he has other health problems, you probably don't want that
additional stress right now.

Certainly ask your vet about it next time you take him in, and use a
good toothpaste (my vet recommends "C.E.T." toothpaste, which you can
get at any vet, as it's commonly used for dogs/cats.)

Kevin

[Posted in FML 5739]