It is an inflammatory disease affecting the gums and the bone supporting the teeth. It is  caused by the presence  of anaerobic bacteria in the bacterial plaque which are able to live and multiply in the absence of oxygen. Genetic predisposition (familiarity) and lifestyles (inadequate plaque removal, smoking) play a very important role in the most acute forms. The initial phase of the disease (gingivitis) is reversible by removing the bacterial plaque by appropriate oral hygiene measures carried out at home and by the dentist. If not treated, the proliferation of the bacteria continues below the gums resulting in the irreversible loss of the surrounding bone that keeps the tooth in place and the formation of gum pockets. Here the bacteria, in the form of plaque and tartar along the surface of the roots, proliferate undisturbed, increasing the pockets depth as bone loss progresses.