Periodontal ligaments

Our teeth have numerous supporting structures, without which their functioning will be rendered useless. And one of the crucial supporting structures of our teeth is the periodontal ligaments.



It is an essential structure because of its numerous functions but do you know how the Periodontal ligament plays a crucial role?

Let’s take a look!

What are periodontal ligaments?

Generally, Periodontal Ligaments or PDL are mistaken as the gum tissues and the bone that holds your teeth in the right place. But, it is a soft tissue that caters to uniting or bridging between your teeth and the bone. The short form of periodontal ligament is PDL, and PDL goes into the bone that surrounds each tooth and the outer root surface layer, which is the cementum.

What is the function of periodontal ligaments?

The periodontal ligaments have four primary functions.

  1. Supporting

    The periodontal ligament is that part of the periodontium that enables the teeth to remain linked to the surrounding alveolar bone via the cementum. The fibers of PDL are also responsible for transmitting and absorbing the forces that are present or generated between the teeth and the alveolar bone.

  2. Providing Nutrition

    The periodontal ligaments guarantee the vitality of the surrounding cells because they are highly anastomose. The three blood vessels carry the nutrients, including gingival, apical, and perforating vessels.

  3. Sensory functions

    The periodontal ligaments are heavily innervated, including nociception, recess, and mechanoreception. Therefore, it is also the reason that activates the sensory functions in our teeth.

  4. Remodeling functions

    The PDL comprises the progenitor cells that are responsible and are available for differentiating into osteoblasts. These cells are considered functional in the alveolar bone’s physiological maintenance and repair functions.

What other role does the Periodontal Ligament (PDL) play?

The periodontal ligament enables the tooth to operate under the force of chewing and absorbs the excess force from clenching and grinding. Additionally, the ligament is involved in tooth movement and contributes to tooth eruption.

The PDL is also responsible for orthodontic tooth movement. If the tooth were linked directly to the bone, it would operate similarly to a dental implant and be immobile. Since the tooth is kept in place by the periodontal ligament and not a direct bone-to-tooth interaction, it may often be retrieved without extensive jawbone removal.

Additionally, the periodontal ligament enables the tooth to adjust to stresses caused by tooth grinding (also known as bruxism) or other jaw-clenching behaviors. The ligament might swell, allowing the tooth to become dislodged. Once excessive stresses are eliminated on the tooth, the PDL will mend, and tooth movement will diminish.

Health issues regarding Periodontal Ligaments

One of the leading reasons for the loss of PDL is advanced gum disease, also called periodontitis. In this disease, the gum tissue starts receding from the teeth, which results in the formation of pockets. It is caused due to the accumulation of bacteria in the pockets that further causes an infection. If the condition is left untreated, it causes the destruction of the bones, tissues, and ligaments in your mouth.

Structure of Periodontal Ligaments

The PDL consists of 70% water, and its width is generally 0.15 to 0.38mm in its thinnest part. Its high water content is why it can offer the teeth sturdy support and strength.

Now let’s take a detailed look at its structure!

  • Alveolodental ligament

The Alveolodental ligament is the primary principal fibers group containing the five different fiber subgroups. The subgroups are the alveolar crest, horizontal, oblique, apical, and inter radicular on multirooted teeth.

  • Transseptal fibers

The Transseptal fibers (H) are the extensions over the alveolar bone crest and are present in the cementum of the adjacent teeth. Teher, they form an interdental ligament. The fibers carry out the function of keeping the teeth aligned.

  • Loose connective tissue

Loose connective tissue consists of fibers, extracellular matrix, cells, nerves, and blood vessels. Here, the cells consist of fibroblast, defense cells, and undifferentiated mesenchymal cells.

  • Cell Rest of Malassez

The Cell Rest of Malassez are groups of epithelial cells placed in the matured PDL after the Hertwig epithelial root sheath disintegrates during the rot formation process.

  • Oxytalan fibers

The Oxytalan fibers are a unique structure in the PDL and are elastic. It gets into the cementum and runs in two directions.

Oral Health Implications

Advanced gum diseases might trigger bone damage and periodontal ligament loss (periodontitis). When a patient suffers from periodontitis, the gum tissue pulls away from the teeth, forming pockets.

The disease-causing bacteria gather in these pockets, creating an infection that, if left untreated, affects the bones, ligaments, and tissues in the mouth and may result in tooth loss. Once the PDL is destroyed, the adjacent bone is no longer connected to the tooth and cannot thus give support.

The periodontal ligament is prone to periodontal inflammation and does not regenerate readily in locations where it has been removed. If a patient’s severe periodontal disease has destroyed the jawbone, a bone transplant might not be successful if the periodontal ligament is not restored simultaneously.

Dr. Michael

Dr. Michael

MSc Implantology, Bonn University, Germany