Bacteria in Plaque can release substance that irritate and inflame gum tissues. This condition is called Gingivitis. When Plaque is not removed, it hardens around the gum line and forms Tartar. The infection then spreads to the bone supporting the tooth and eventually, the tooth may fall out. This is called Periodontal disease or Pyorrhea. Gum diseases may also take the form of a gum boil which results from infected pulp. As pus collects, it works its way through the end of the root and into the jaw bone and pushes out the gum to resemble a boil.