Ankylosed tooth

What is dental ankylosis?       

Histologically, the replacement of the periodontal ligament by calcified tissue can be observed, attaching the tooth directly to the bone, stopping or preventing tooth eruption.

In order to understand more fully what dental ankylosis is, it is necessary to know the following points:

  1. The teeth are not directly attached to the bone. The bone simply supports them, creating an armor around the tooth root.
  2. Some fibers, called periodontal ligament fibers, are actually responsible for the union between the bone and the tooth. These prevent teeth from moving out of place just by touching or chewing.
  3. The periodontal ligament also provides cushioning during movements, such as occlusion and chewing, becoming a kind of mattress that prevents direct friction between two hard components – the bone and the teeth – preventing the problems this can cause.
  4. Sometimes the periodontal ligament layer disappears, totally or partially, in some teeth. This produces a direct fusion between the components of the tooth and the bone, creating a weld that makes their anatomical separation almost impossible.

What happens is that finally, the jaw bone fuses with the cement or dentin, the substances that form the root of the tooth. This can prevent proper eruption and tooth movement.

Ankylosis can occur in one or more teeth, both in the permanent and temporary dentition, where it occurs most frequently (in a ratio of approximately 1 to 10). It is especially damaging to the mandibular molars.

What is dental occlusion?

In dentistry, the relationship formed when the upper and lower teeth come into contact, such as when you bite, is called occlusion. Occluding the action of bringing both jaws together. The relationship can be good or bad; in the latter case, it is called dental malocclusion.

During occlusion, it is expected that all the teeth of the upper jaw will come into contact with one or more partners of the lower jaw or opposing arch. When a tooth, during occlusion, fails to have any contact with at least some of the opposite arch, this tooth is said to be in infraocclusion or sub-eruption, and it generally looks smaller than the others.

It can happen that a tooth looks longer than its neighboring teeth. In this case, it will be said that the tooth is in over occlusion or that it is overerupted.

Here are the most common local factors:

  • A congenital defect or disturbance in the metabolism of the periodontal membrane.
  • Excessive force during chewing.
  • Tooth clenching or bruxism.
  • A metabolic abnormality in the bone, especially the jaw
  • An infection that affects the tooth and/or jawbone
  • The constant pressure of the tongue on the affected teeth
  • The formation of a space between the periodontal ligament and the tooth
  • Trauma to the alveolar bone or periodontal ligament
  • It has also been related on occasions to the early loss or congenital absence of the milk tooth that precedes the permanent one, creating a bone bridge difficult to overcome by the permanent one during its eruption.

Signs and symptoms of a dentoalveolar ankylosis

The main symptoms of dental ankylosis are:

  • A tooth with ankylosis is generally below the occlusal plane – shorter than its peers – as if it had not yet finished emerging.
  • The teeth in their natural state have an almost imperceptible degree of mobility; an ankylated tooth totally lacks some type of mobility.
  • There is the retention of a deciduous tooth, despite having long exceeded the time it should have remained in the mouth.
  • Misalignment – or crooked teeth – of the affected jaw teeth may be seen.
  • In some cases, the under-eruption of a tooth will produce an over-eruption — the tooth will appear longer than its neighbors — of its partner in the opposing jaw.

What are the consequences of a dental ankylosis?

When dental ankylosis is not discovered and treated in time, it can trigger other associated problems, especially for the eruption and normal development of the jaws. Some of these problems are:

  • Loss of diameter of the dental arch.
  • The inclination of contiguous teeth.
  • Loss of space.
  • The affected tooth does not enter into occlusion or contact with the teeth of the opposing arch.
  • Malocclusions especially crowded teeth and a localized open bite.
  • Chewing disorders.
  • If the submerged tooth is deciduous, there may be a retention of the permanent tooth within the jawbone.
  • Loss of the molar in retention and as well as that of the neighboring teeth if there is periodontal disease or cavities.
  • Deformation of the facial skeletal structure.
  • Relative mandibular prognathism.
  • Posterior open bite.
  • Deviation from the midline.
  • It can affect the vertical growth of the alveolar bone.
  • There is an increased risk of tooth decay and periodontal disease, as poorly positioned teeth make oral hygiene difficult.

What are the types of dentoalveolar ankylosis that exist?

According to its degree of severity, dental ankylosis can be classified as follows:

  • Mild ankylosis: the tooth is a maximum of 2 millimeters below its peers or in infraocclusion.
  • Moderate ankylosis: the tooth is in infraeruption, but there is some type of contact with the neighboring teeth.
  • Severe ankylosis: In general, the tooth with this type of ankylosis does not erupt and is hidden within the jawbone or does not have proximal contact with its partners.

How can ankylosis be treated?

For the proper treatment of ankylosis, two important steps must be followed:

  1. Making a diagnosis
  2. Establishing a good treatment plan

Diagnosis of ankylosis

Conducting a proper diagnosis is vital to ensure timely treatment to prevent unintended consequences, in this case, dentoalveolar ankylosis. For the diagnosis, the dentist will resort to a clinical evaluation. It is based on symptoms and observation such that a radiographic study will show the relationship between the tooth, the periodontal ligament, and the root surface.

Treatment of dentoalveolar ankylosis

Orthopedics Is a specialization within dentistry that focuses not only on studying and correcting the growth problems of the oral structure, but also of the facial bone structure.

Orthodontics is the branch of dentistry that deals with problems of the teeth and jaw. Orthodontic dental care includes the use of such devices as braces (braces) to straighten teeth and correct problems with the bite.


It is not known with certainty why dentoalveolar ankylosis is generated, but several theories about the causes of this alteration have been mentioned. One states that any discontinuity in the periodontal ligament can predispose one to the development of ankylosis. It has also been associated with an injury to the bone or periodontal ligament due to trauma, which leads to degenerative processes that produce a union of the tooth to the bone.

The presence of localized infections, chemical irritation, congenital defects of the periodontal membrane, excessive chewing pressure, and abnormal pressure of the tongue on alveolar ridges or erupting teeth have also been associated as possible etiological factors of ankylosis.

It has been observed that this alteration can cause harmful effects on the development of the dentition and therefore a timely diagnosis and effective treatment plan are essential to prevent deviations of the eruption and functional alterations of the oral cavity.

The diagnosis of ankylosis must be made clinically and radiographically. It should be noted that radiographic evaluation is one of the most important diagnostic methods in patients with ankylated teeth since, in panoramic and periapical radiographs, the main signs of this anomaly can be observed, such as the loss of the periodontal ligament space or absence of continuity in the area where ankylosis has occurred. 

Similarly, fewer radiopaque roots are seen and the surrounding bone is difficult to distinguish. When dentoalveolar ankylosis occurs early, it tends to have a greater impact on dental occlusion. Over time, the infraocclusion increases as the physiological dentoalveolar development of the ankylated tooth stops, and the alveolar process of the adjacent teeth continues its normal vertical growth; Therefore, the earlier this alteration occurs, the greater the degree of infraocclusion.

Early treatment is aimed at intercepting any condition that may influence the growth pattern, tooth development, and eruption. Timely intervention of ankylated teeth is indicated to prevent or control the occlusal and eruptive disturbances previously described.

The follow-up should be carried out by means of biannual clinical and radiographic examinations, where the physiological root resorption, the degree of infraocclusion and the development of the successor permanent tooth should be evaluated.

Contact us Ankylosed tooth

If you have any questions about this or other topics, you can contact us at Channel Island Family Dental as well as our Facebook page. We look forward to your visit and will make a timely diagnosis. Our dentists in Oxnard, Santa Paula, Ventura, Newbury Park, and Port Hueneme will be able to guide you towards the best treatment to take care of your health and return your best smile.

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