Periodontology: Definition, Functions, Structures and Diseases Associated with These Ligaments

It is a source of stem cells that maintains homeostasis and allows regeneration.

Also of several signaling factors essential for dental and bone tissue communication .

Function of the periodontium

The main functions of the periodontium include protecting teeth, nerves, and blood vessels against injury from mechanical forces; fixation of teeth to bone; and the transmission of occlusal forces and sensation to stimuli (such as temperature and pain).

Structures of the periodontium

The periodontium is made up of the supporting structures of the teeth , it is made up of four different types of tissue, the gingiva, the alveolar process, the cementum and the periodontal ligament.

These structures vary in their cellular composition, types and amounts of proteins, mineralization, degree of metabolic activity, and susceptibility to disease.

The gum

The gingiva is the tissue that covers the periodontium and offers immediate protection for the underlying tissues, as well as the additional attachment of the tooth.

The gum is the keratinized mucosa that surrounds the teeth. It forms a collar around each tooth, which varies in width from 1 to 9 mm.

The narrowest area of ​​the gingiva is generally located on the buccal surface from the mandibular canine to the first premolar region.

The widest area is often found on the lingual aspect of the last mandibular molar.

The gingiva is partly attached to the cementum of the tooth and partly to the alveolar process. The gingiva is made up of chewing mucosa.

The interdental gingiva is located between the teeth and usually fills the gaps between the teeth, working to divert food from these areas.

Between the anterior teeth, the gums are usually wedge-shaped, and in the posterior teeth they assume a saddle-shaped configuration.

Farther from the crowns, the gingival epithelium is strongly keratinized and attached to the underlying structures, including the hard palate called keratinized gingival tissue.

These tissues abruptly transform into a non-keratinized epithelium that covers the cheeks, the floor of the mouth, and the posterior pharynx and is called the alveolar mucosa.

The gingival crevice (a fist-like space between the gum and the teeth) is a blind cul-de-sac.

This area is limited laterally on the side of the tooth by a specialized epithelium called the sulcular epithelium.

The sulcular epithelium transitions into a tissue called the junctional epithelium that is positioned at the base of the crack.

In health, it is thought that through an active desquamation process of epithelial cells, the underlying tissues are protected from bacterial invasion.

The alveolar process

The alveolar process is made up of three different structures, the alveolar bone itself (lamina dura), the trabecular bone, and the compact bone.

The alveolar bone is attached to the teeth through the fibers of the periodontal ligament, which form the tooth socket.

The crest of the alveolar supporting bone, often seen on typical dental radiographs, is approximately 2 mm below the point where the enamel of the crown of the tooth meets the root cementum (the cementum-enamel junction).

The bone holds the tooth in place in the oral cavity. The configuration of the bone follows the shape of the tooth root.

The lamina dura is radiographically distinct and covered by compact bone.

The lamina dura serves to anchor the fibers of the periodontal ligament. Compact bone and lamina dura cover a complex pattern of trabecular bone.

The configuration of the bone corresponds to the course of the union of the teeth with cement and enamel.


The surface of the root is called the cementum. Cement is a thin cellular layer that covers the surface of the root and acts to protect the tooth from external injury.

Connective tissue junctions are present between the alveolar bone and the cementum.

The periodontal ligament

The periodontal ligament connects the cementum of each tooth with the surrounding alveolar bone in both the maxilla and the mandible in humans.

Because the periodontal ligament is visible radiographically, an increase in the width of the ligament may indicate disease.

Associated diseases

Among the most common dental diseases, periodontitis, the most prevalent disease in people over 30 years of age, destroys the periodontium irreversibly and permanently.

Currently, no effective regeneration measures are available for the destroyed periodontium, but tissue regeneration using stem cells
has been a promising candidate for the purpose of periodontal regeneration.

The periodontium includes the inversion and supporting tissues of the teeth, and consists of the fixation apparatus and the dentogingival unit.

The degeneration of the periodontium is likely to be accelerated in the presence of:

  • Specific intrinsic biological factors (i.e., the individual’s biotype), which may include a basal mandible discrepancy with malocclusion.
  • The agglomeration of the dental roots within the alveolar bone limited.
  • A forced mouth breathing pattern, and an inadequate amount of attached gingiva at the clinical interface of the crown of the teeth.
  • Active infection or inflammation of the periodontium.
  • Non-biological restorations at the dental-gingival interface.
  • The paraoclocclusal habits.
  • Oral toxins and poor oral hygiene.

When healthy, the tissue has a scalloped edge with a thin edge and is generally pink in color, although variations in color are evident between different races and ethnicities.

The free gingiva extends from the gingival margin to include the interdental papilla.

In good health, the interdental papillae fill the interproximal space and spread in contact with the two adjacent teeth.

On contact, there is a slight “drop” in the tissue below the contact, it is most prominent on the posterior teeth, both in the upper jaw and the mandible, where the contact is the widest.

The mucogingival line demarcates the attached gingiva. The attached gingiva, in a healthy state, is firm against the periosteum with the presence of stippling.

Due to the ease of visualization and the relationship to the more destructive disease process, changes in gingival tissues are used routinely to measure changes in gingival health.

Vascular supply

The periodontium is a complex organ, unique because it provides a portal to the systemic organism through the extensive vasculature of the gingival tissue, which covers the alveolar process.

Vascular supply is provided in the upper jaw by the superior alveolar artery, and the inferior alveolar artery provides supply in the mandible.

The branches of these arteries supply the highly vascular gingival tissue, bone, and supporting structures.

The maxillary vasculature comprises the terminal branches of the dental artery, the posterior alveolar artery, the infraorbital artery, and the greater palatal artery, which are terminal branches of the inferior alveolar artery and the posterior alveolar arteries.

The branches of the facial artery, the mental artery, the buccal artery, and the sublingual artery comprise the mandibular vasculature. These vessels provide a complex and interdependent vascular network.

Lymphatic drainage through the submandibular lymph nodes is performed in most periodontal tissues.

The submental lymph nodes and the cervical lymph nodes play a minor role in lymphatic drainage from the oral cavity.