What is periodontitis?: Dr Ros O' Leary, Periodontist
The main difference between gingivitis and periodontitis, is that gingivitis only affects the gums and it is completely reversible. It affects all people - if you don't clean your teeth properly, and you have plaque and tartar on your teeth, you will get inflammation of your gums.
Periodontitis is a more serious disease. It also causes you to have inflammation of your gums, but it also causes you to lose the bone from around your teeth, and bone loss due to gum disease is irreversible. Once it is gone you will never ever get it back again. So if it continues, you can lose your teeth.
It is partially down to your genetic susceptibility. So some people are much more susceptible to the disease than others. It is exacerbated by smoking, people who have diabetes, other medical conditions - so it is a much more general problem, and and it is much more difficult to treat.