There are two main causes for a cat litter box problem. One is behavioral, and the other is physical. Before assuming it's a behavioral problem, you should always bring your cat to the vet so that you can rule out any physical causes. As you read this, keep in mind that your cat will form an association with her experiences, either good or bad. So, if your cat has a bad experience in the litter box, she may associate negative feelings with it. If those feelings are strong enough, perhaps due to repeated bad experiences, she may refuse to use the box at some point.
No matter the breed, cats can get a lot of teeth and gum problems. These sort of diseases are not harmless or isolated at all, eventually leading to serious systemic problems for your cat. The figures have shown that over 70% of all cats older than two years are suffering from some form of dental disease.
A chronic condition occurring in cats that causes extreme gingivitis and tooth loss is Plasmacytic-Lymphocytic Stomatitis. This disease is usually a result of another disease. It has been found in cats with Feline Leukemia and Feline Immunodeficiency. The symptoms are salivating excessively, trouble eating, and a really foul odor in their mouth. Naturally this soreness in their mouth causes them not to eat and they lose weight rapidly.