How does the periodontium work?

The periodontium keeps our teeth firmly in place in the mouth. It is made up of four parts:

  • Tooth sockets (dental alveoli)
  • Periodontal ligament
  • Cementum
  • Gums (gingiva)

The holes in the jaws that contain the roots of the teeth are called tooth sockets, or dental alveoli. The jaws and the walls of the tooth sockets are made up of bone tissue. This part of the periodontium is not usually visible. 

Illustration: Periodontium - as described in the articlePeriodontium

The teeth are connected with the walls of the tooth sockets and anchored in the jaws by the periodontal ligament and the cementum. The ligament is made up of connective tissue and contains collagen fibers. These fibers are especially strong so that the teeth can withstand the great pressure put on them while we chew. The teeth can also move slightly in the ligament to compensate for the pressure exerted by chewing. In contrast, dental implants are firmly attached to the jawbone and are not able to move. In addition to connective tissue and collagen fibers, the ligament contains blood vessels and nerves: the blood vessels supply the ligament with nutrients, while the nerves are responsible for controlling the amount of force used while chewing.

The actual tooth has an outer layer of cementum around its root. The cementum is mostly made up of minerals, but also contains collagen fibers. It is very tightly connected to the ligament, binding the root of the tooth to the rest of the periodontium. The outer layer of the tooth gradually changes from cementum to dental enamel near the neck of the tooth.

The gums (gingiva) cover and protect the ligament and the neck of the tooth, and are usually the only visible part of the periodontium. The gums fit tightly around the teeth like a collar. They turn slightly inward where they meet the teeth, forming a narrow groove.

The gum tissue can easily become inflamed, causing it to slightly detach from the neck of the tooth. The groove between the tooth and the gum can then deepen to form what is referred to as a pocket. Bacteria rapidly build up in these pockets. Inflammation of the gums (gingivitis) can be visible as bleeding gums, but often does not cause any symptoms. Sometimes gingivitis can lead to periodontitis, an inflammation of the periodontium that attacks the gums as well as the bone of the jaw. Advanced periodontitis can cause teeth to become loose and fall out, or require them to be removed.