Gingivitis is the mildest form of periodontal disease where inflammation of the gums (gingiva) develops. Infection and inflammation spread from the gums to the ligaments and bone that support the teeth. Left untreated, loss of support causes the teeth to become loose and eventually fall out. 
Unhealthy teeth and gums have a greater impact on the body than just causing bad breath, pain, and infection. As the gums have a rich blood supply, bacteria is readily transported to other organs (such as the liver, kidneys etc.) in the body causing damage and even organ failure.
Dental disease: Gingivitis is caused by a build-up of plaque (bacteria and food debris). In the early stages, plaque forms on the teeth, if it isn’t removed, it hardens and becomes tartar (also known as calculus). Tartar is yellow in colour and is seen along the gumline, where it meets the teeth.
Plasmacytic-Lymphocytic Stomatitis (LPGS): This is a severe form of gingivitis-causing extreme pain. The cause is still unknown. It appears to be a hyperactive immune response. Feline calicivirus, FIV, and FeLV have all been implicated.
Treatment depends on how far advanced the gingivitis is. It may be possible to treat early gingivitis at home with regular dental cleaning.
Gingivitis which is more advanced requires regular dental cleaning (every 6 months) and extraction of diseased teeth.
Cats are expert at masking discomfort and pain and many pet owners may not notice that their cat has a problem. This is another important reason why regular, annual check-ups with the veterinarian are so important. Even if you believe your cat is in good health, a thorough physical may uncover a problem in the early stages. Gingivitis is reversible if if the necessary treatment is provided. Gingivitis is reversible if the cat receives prompt treatment. If it is left to progress to periodontal disease, the damage is irreversible.
Regular descaling by your veterinarian.
Diligent home dental care in the form of regular brushing of your cat’s teeth.