There are two important aspects to feline gum disease which come to my mind…(a) gum disease is fairly common, almost universal – one of the top 10 most common cat health problems (probably) and (b) it it easy to overlook it because cats don’t complain and it is quite tricky to get a good look into the mouth of a cat and particularly where gum disease is most likely to be: at the back of the upper jaw on the outside.
From personal experience this is exactly the same place where humans have bleeding gums (and I address that issue briefly below as well).
The signs of bad mouth disease (which effectively is gum disease + teeth problems) is drooling and a reluctance to eat but, an easy way to check is to:
Run a cotton bud around the gum line. I’d focus on the back of the mouth, upper jaw. When the cotton bud is removed it should be clear of blood. If not, it is time for vet visit.
I think this is a good tip because it is not that difficult to surreptitiously run a cotton bud along the outside gum line of a cat (but it must be at the back). I don’t expect a person to have more than about five seconds to do this before their cat tells them to stop (politely I hope). But it is workable.
The alternative is to pull back the lips and skin of the mouth which cover the gums at the back and a cat will dislike this more and in any case, as a test, it is less conclusive.
Now..about humans. If you have bleeding gums when you brush your teeth it will be because of the gums at the back of the mouth on the outside and on the upper jaw which are inflamed because you are not getting to that area.
I’d recommend a battery driven tooth brush because they can get into smaller areas more effectively and focus on the back upper outside and inside of the gums. The same goes for lower jaw but to a lesser extent.
This should be followed up with a good commercial mouth wash. There are lots of them.
You won’t have bleeding gums anymore. Dentists don’t usually tell you this because they want you to have bad gums and teeth.