Reviewed by Dr. Manish Pandey, BDS, Dental Surgeon
Tooth ankylosis happens when part of a tooth root becomes fused directly to the surrounding jawbone and the normal periodontal-ligament space is lost. The tooth may look “sunken” or shorter than nearby teeth, especially while a child is growing. Early assessment matters because an ankylosed tooth can affect eruption, spacing, bite development and future treatment choices.
What is tooth ankylosis?
Normally, a thin periodontal ligament separates the tooth root from its socket and allows tiny physiologic movement. In dental ankylosis, cementum on the root joins directly to alveolar bone. The affected tooth cannot erupt normally with the rest of the dentition. In a growing child, neighboring teeth and bone continue developing while the ankylosed tooth remains at the same level, creating infraocclusion.
What are the signs of an ankylosed tooth?
The most noticeable sign is a tooth that sits below the biting level of adjacent teeth. Other possible findings include:
- little or no normal tooth mobility;
- a different, often sharper or more solid sound when the dentist gently taps the tooth;
- tilting of neighboring teeth or loss of space;
- delayed eruption of the permanent successor;
- an uneven bite; or
- after trauma to a permanent tooth, progressive replacement resorption.
An ankylosed tooth is not always painful. Absence of pain does not mean it should be ignored.
Why does tooth ankylosis happen?
The exact cause is not always identifiable. In primary teeth it may arise without a clear event. Family tendency, local inflammation or previous injury may contribute. In permanent teeth, ankylosis is particularly associated with significant trauma to the periodontal ligament, including severe intrusion or replantation after a tooth has been knocked out.
How is tooth ankylosis diagnosed?
A dentist combines the history, clinical examination and dental radiographs. The tooth’s height, mobility and percussion sound are compared with adjacent teeth. An X-ray may show interruption of the periodontal-ligament space, external root resorption or bone replacing root structure, although early or small ankylosed areas may not be obvious on a two-dimensional image.
Other causes of delayed eruption or a “submerged” tooth must be considered, including a physical obstruction, an abnormal eruption path and primary failure of eruption. Diagnosis should therefore not be made from a photograph alone.
Does every ankylosed tooth need removal?
No. Management depends on whether the tooth is primary or permanent, the child’s growth stage, the degree and progression of infraocclusion, the presence of a permanent successor, available space and the overall orthodontic plan.
Ankylosed primary tooth
A mildly affected primary molar may sometimes be monitored if it is not blocking eruption or causing neighboring teeth to tip. When it interferes with eruption, produces increasing infraocclusion or threatens arch space, extraction and space management may be considered. See our guide to a space maintainer for children for related information.
Ankylosed permanent tooth
Options are individualized and may involve restorative build-up for minor height differences, orthodontic and surgical approaches, decoronation in selected growing patients, extraction, or later prosthetic replacement. No home remedy can separate a tooth fused to bone. Complex cases often need coordinated planning by a dentist, orthodontist and oral surgeon.
What happens if an ankylosed tooth is left untreated?
Some stable cases can be observed safely, but progressive ankylosis may lead to loss of arch space, tipping of adjacent teeth, bite disturbance and a vertical bone defect. After trauma to a permanent tooth, replacement resorption can gradually replace root structure with bone. The rate varies, so regular clinical and radiographic review is important.
When should you see a dentist?
Book an examination if a child’s tooth appears lower than neighboring teeth, a baby molar has not loosened when expected, a permanent tooth is delayed, or a previously injured tooth changes position or color. Seek urgent dental care after a knocked-out permanent tooth or major intrusion injury. Do not attempt to loosen, pull or repeatedly tap a suspected ankylosed tooth yourself.
Frequently asked questions
Can an ankylosed tooth move with braces?
Because the root is fused to bone, conventional orthodontic force alone usually cannot move a truly ankylosed tooth. A specialist must confirm the diagnosis and assess other treatment options.
Can tooth ankylosis be seen on an X-ray?
Radiographs can show loss of periodontal-ligament space or replacement resorption, but early or limited ankylosis may be difficult to see. Clinical findings remain important.
Is an ankylosed baby tooth dangerous?
It is not usually an emergency, but it can interfere with eruption and spacing. Timely dental monitoring helps determine whether observation or treatment is appropriate.
Will an ankylosed tooth fall out naturally?
Some ankylosed primary teeth may exfoliate, but others remain submerged or obstruct the permanent successor. Permanent ankylosed teeth generally do not resolve on their own.
Key takeaway
A tooth that looks submerged, fails to erupt or follows significant trauma deserves professional evaluation. Early diagnosis allows treatment to be timed around growth, eruption and long-term bone preservation.
Dental disclaimer: This article provides general educational information and cannot diagnose or replace an examination by a dentist. Treatment for tooth ankylosis must be individualized after clinical and radiographic assessment.
References
- American Academy of Pediatric Dentistry: Management of the Developing Dentition and Occlusion
- NCBI MeSH: Tooth Ankylosis
- Campbell KM, Casas MJ, Kenny DJ. Ankylosis of traumatized permanent incisors
AI-generated illustration for educational purposes only.