Greetings Nota,
While I can't answer your question about dental problems, as I have no first hand experience with it. I can tell you absolutely that Diabetes is no more of a death sentence for a cat than it is for a person. It is managed exactly the same way, diet, insulin, and blood glucose testing at home before each and every shot. In fact it is so easy to manage that not only did I adopt one cat because he was a diabetic, I have adopted two. Maxwell & Musette, now since before adopting my two lovely diabetics I already had 10 non-diabetics...yes TEN! I really didn't have to go out of my way to adopt a special needs animal of any type, but I sure wouldn't trade in my sugarcats now.
Diabetes is one of those things that is best managed at home, in partnership with your vet. The three keys is first learning to test blood sugar at home, we use the exact same meters as a human diabetic does, we simply prick the edge of our cat's ear, like a human does their finger tip. Next comes diet, a diabetic cat, like a human diabetic needs to be on a low carbohydrate diet. Most of us feed canned pate style catfood. Not sure what brands you have available in Greece, but here in the US and in my house we use Friskies, 9-lives and Wal-mart's house brand Special Kitty. I know many here use Fancy Feast as well. Basically anything that doesn't say "In Gravy" and is either pate or loaf style. But if Mafalda is use to eating dry food you will want to be home testing before changing diet as just removing the high carb food that dry is, can dramatically reduce blood glucose. Lastly, although sometimes started before the diet change, is insulin. Which is just two tiny shots given under the skin twice a day, 12 hours apart.
And the best part is that now that you have found us, we can help you with every step of the process, short of actually prescribing the insulin. When you can or when you know, let us know what insulin your vet has prescribed and at what dose, as that will allow us to help you better. For now, read all the stickies (starred posts at the top of the page) and ask any questions you might have.
Oh yeah remember to just Breathe, and Welcome to the Family!
Mel, Maxwell, Musette & The Fur Gang