Dental Ankylosis

Dentoalveolar ankylosis causes an abnormal eruption of the tooth due to a fusion of the root, more specifically the dental cementum, to the alveolar bone surrounding it. This is possible due to the local elimination of the periodontal ligament.

The exact etiology remains unknown, however there are many possible causes identified for ankylosis such as:

• Dental Trauma
• Metabolic disturbances
• Genetic tendencies
• Local deficiency in vertical bone growth

The fusion of the root to the surrounding alveolar bone has many effects on the tooth itself and to the teeth surrounding it such as:

• Root resorption of the ankylosed tooth and substitution by bone
• Progressive infraocclusion
• Inclination of the surrounding teeth
• Impaction or delay of eruption of permanent teeth (if the ankylosed tooth is deciduous)
• Midline shift to the ankylosed side
• Extrusion of the antagonist tooth
• Local malocclusion

It is important to diagnose dentoalveolar ankylosis as early as possible to minimize it’s impact on occlusion. The later the diagnosis, the more complicated the treatment and the more advanced the eruption deviations and malocclusion. It can be diagnosed both clinically and with radiographs. Clinically is can be identified by:

• An infraocclusion
• Percussion tests (high pitch percussion tone)
• Mobility testing
• A lack of response to orthodontic treatments

The incidence ranges from 1.5-9.9% in primary dentition.

It is 10 times more frequent in deciduous teeth.

It is 2 times more frequent in the mandible than the maxillary.

It is much more frequent in the molar region during deciduous and mixed dentition.

OMIM Orphanet