--- title: "Ankylosed Teeth and Orthodontics UK | When a Tooth Cannot Move" url: https://virtualconsultant.online/guides/ankylosed-teeth-orthodontics-uk description: "Ankylosis fuses a tooth directly to bone, making orthodontic movement impossible. UK 2026 guide covers infraocclusion, percussion testing, decoronation." updated: 2026-09-07T00:00:00Z publisher: Virtual Consultant Online --- Ankylosis Infraocclusion Tooth Movement # Ankylosed Teeth and Orthodontics: When a Tooth Cannot Be Moved An ankylosed tooth has fused directly to the surrounding bone — there is no periodontal ligament left to transmit orthodontic force, so standard brace or aligner treatment cannot move it. This guide explains how ankylosis develops, how it is diagnosed, what infraocclusion looks like in children, and which treatment options — decoronation, extraction, or implant planning — are appropriate at different stages. [Start Photo Assessment](https://virtualconsultant.online/evaluations/quote) [Compare Costs](https://virtualconsultant.online/costs) ## What ankylosis is Ankylosis describes the pathological fusion of the cementum or dentine of a tooth root directly to the surrounding alveolar bone. Normally, teeth are suspended in their sockets by the periodontal ligament (PDL) — a fibrous connective tissue that acts as a shock absorber and provides the biological mechanism for orthodontic tooth movement. In ankylosis, the PDL is partially or completely obliterated and replaced by a direct bone-to-tooth union. Without a functional PDL, the tooth behaves as if it is rigidly embedded in the jaw rather than suspended within it. The tooth cannot respond to orthodontic force in the usual way, and applying force to an ankylosed tooth risks damaging adjacent teeth and bone rather than moving the ankylosed tooth itself. ## How ankylosis develops Ankylosis most commonly follows trauma to the tooth or supporting structures. A tooth that has been luxated, avulsed and replanted, or subjected to a significant blow can undergo replacement resorption — a process where the immune system gradually replaces root cementum and eventually root dentine with alveolar bone. Infection, periapical pathology, and dentoalveolar surgery can also disrupt the PDL and initiate ankylosis. In some patients, particularly children, primary (deciduous) molars undergo idiopathic ankylosis with no identifiable cause, resulting in infraocclusion as the surrounding jaw continues to grow downward while the ankylosed tooth remains at its original height. A genetic predisposition has been identified in some families with multiple affected primary molars. ## How ankylosis is detected Three methods are used in combination to diagnose ankylosis. The percussion test is the simplest: when tapped with a dental instrument, an ankylosed tooth produces a dull, solid, high-pitched sound quite different from the hollow, lower resonance of a normally suspended tooth. This test is clinically reliable but requires an experienced clinician for accurate interpretation. Radiographic assessment using a periapical or panoramic radiograph shows loss of the PDL space in the affected region, though early or partial ankylosis can be difficult to detect radiographically. Cone beam computed tomography (CBCT) provides a three-dimensional view of the PDL and is the most sensitive imaging method for confirming the extent of bone-tooth fusion, particularly when treatment planning decisions depend on an accurate diagnosis. Infraocclusion — where the tooth sits below the occlusal plane — is a reliable clinical indicator of long-standing ankylosis in growing patients. ## Infraocclusion in children and its consequences Infraocclusion refers to the submerging appearance of an ankylosed deciduous molar as the jaws grow and adjacent teeth erupt to a higher occlusal level while the ankylosed tooth stays put. In mild cases, infraocclusion causes only a minor step in the dental arch. In severe cases, the ankylosed molar can become deeply buried beneath the gum and bone, with the adjacent permanent teeth tipping significantly over it. The consequences include: blocked eruption or ectopic displacement of the underlying second premolar, tipping of adjacent first permanent molars, loss of arch length as adjacent teeth drift, bone deficiency on the affected side of the arch, and in extreme cases, the ankylosed tooth becoming entirely submerged. The rate of submergence is related to the rate of jaw growth — it is fastest during the pubertal growth spurt and in patients with rapid vertical facial development. ## Why ankylosed teeth cannot be moved orthodontically Orthodontic tooth movement depends on the piezoelectric and biological response of the PDL to sustained mechanical force. Pressure on the PDL stimulates osteoclastic resorption on the compression side, while tension on the PDL stimulates osteoblastic bone deposition on the tension side — the combination produces tooth movement through bone. An ankylosed tooth has no functional PDL. Applying orthodontic force to it does not produce the expected PDL response. Instead, force is transmitted directly to the bone, which can cause root resorption of the ankylosed tooth itself or tipping of adjacent teeth if the force is redirected. In rare clinical situations, very short-duration high-force techniques or surgical luxation have been used to attempt movement of partially ankylosed teeth, but these approaches are not predictable and are not standard practice. ## Treatment options — decoronation, extraction, monitoring The optimal treatment for an ankylosed deciduous molar with a present, erupting successor premolar is often monitoring until the premolar is ready to erupt, then extraction of the ankylosed molar timed carefully to allow the premolar to complete its eruption. Where infraocclusion is severe and causing significant arch disruption, extraction is preferred earlier. Decoronation is a surgical procedure in which the crown and most of the root are removed but the ankylosed root fragments are intentionally left in the bone. This preserves the alveolar bone volume — critically important in growing patients and in those being planned for a future implant — while eliminating the functional problems caused by the retained tooth. For ankylosed permanent teeth in adults, extraction followed by space closure orthodontically or space maintenance for a future implant are the two main pathways, chosen based on arch length, the adjacent teeth, and the patient's restorative needs. ## Implant planning after extraction of an ankylosed tooth When an ankylosed permanent tooth is extracted, the subsequent treatment depends heavily on whether adequate bone volume is preserved. Decoronation, when performed at the right developmental stage, has been shown to preserve significantly more alveolar bone than conventional extraction — a crucial consideration since dental implants require a minimum bone width and height. In young patients who have not yet finished growing, implant placement should be deferred until facial growth is substantially complete, which is typically around 18 to 20 years in females and up to 21 in males. Placing an implant in a growing jaw causes the implant to behave like an ankylosed tooth itself — it will fall progressively into infraocclusion as the jaw continues to grow. Orthodontic treatment is often required before implant placement to ensure the space is the correct width and the adjacent tooth roots are appropriately diverged to allow implant positioning. ## Managing spaces adjacent to ankylosed teeth Ankylosed teeth cause adjacent teeth to tip and drift, creating arch length discrepancies that must be corrected before definitive restoration. Orthodontic treatment is frequently needed to upright tipped molars, create or restore the correct space for a replacement tooth, and ensure root parallelism. In patients where the space has been lost significantly due to prolonged drift, space regaining is more complex and may involve distal movement of the drifted molar. Temporary anchorage devices (TADs) and skeletal anchorage are particularly useful in these situations because they allow movement of multiple teeth without requiring reciprocal anchorage from teeth that may already be compromised. A multidisciplinary treatment plan coordinating the orthodontist, oral surgeon, and restorative dentist is essential. ## NHS vs private treatment for ankylosis NHS treatment for ankylosed deciduous teeth and their orthodontic consequences is generally available for eligible patients under 18, particularly where the IOTN score reflects the severity of the arch disruption or the difficulty of premolar eruption. Surgical procedures including decoronation are available via NHS oral surgery referral. For adults with ankylosed permanent teeth requiring orthodontic space management and implant planning, NHS coverage depends on the specific clinical circumstances; complex restorative and implant work is often private. An orthodontic assessment with a specialist is the best starting point to understand the full treatment pathway and associated costs. ## Useful related pages [Dental Trauma and Orthodontics](https://virtualconsultant.online/guides/dental-trauma-orthodontics-uk) [Orthodontics Before Implants](https://virtualconsultant.online/guides/orthodontics-before-implants-uk) [CBCT vs OPG X-ray](https://virtualconsultant.online/guides/cbct-vs-opg-xray-uk) [Hypodontia and Orthodontics](https://virtualconsultant.online/guides/hypodontia-orthodontics-uk) [Orthodontics with Crowns and Implants](https://virtualconsultant.online/guides/orthodontics-with-crowns-implants-uk) This guide is for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist. ### Compare next steps [Orthodontist Near Me](https://virtualconsultant.online/locations/orthodontic-treatment-near-me) [Clear Aligners Near Me](https://virtualconsultant.online/treatments/clear-aligners-near-me) [Invisalign Near Me](https://virtualconsultant.online/locations/invisalign-provider-near-me) [Browse Locations](https://virtualconsultant.online/locations) ### Ready for a clearer starting point? Upload guided photos and receive an indication of likely treatment options and pricing before booking appointments. [Get an Online Quote](https://virtualconsultant.online/evaluations/quote) ### Frequently Asked Questions Can an ankylosed tooth ever be moved with braces or aligners? In most cases, no. The absence of a functional periodontal ligament means there is no biological mechanism through which orthodontic force can produce predictable tooth movement. Applying force to a fully ankylosed tooth is more likely to damage adjacent structures than to move the ankylosed tooth. Management therefore focuses on extraction, decoronation, or long-term monitoring rather than attempting movement. What is the difference between infraocclusion and a tooth that has not erupted yet? A tooth that has not yet erupted sits within the bone and has not penetrated the gum. Infraocclusion describes a tooth that has erupted and was once at or near the occlusal level but has become submerged as the jaw grew around it while the tooth — fused to the bone — remained stationary. Radiographically, an infra-occluded tooth is often at or below the bone crest, while an unerupted tooth sits within a follicle in the developing bone. Should an ankylosed baby molar always be extracted? Not always — the decision depends on the degree of infraocclusion, the presence and position of the successor premolar, and the patient's age. Mildly infra-occluded baby molars with an erupting successor and no significant arch disruption are often monitored rather than extracted immediately. Extraction timing is critical: too early may leave a space that closes before the premolar is ready to erupt; too late increases the risk of blocked eruption and significant arch disruption. What is decoronation and why is it done instead of extraction? Decoronation removes the crown and most of the root while leaving the ankylosed root fragments intentionally within the bone. The rationale is that leaving the root fragments in place stimulates the overlying bone to fill in over them, preserving the alveolar bone ridge rather than causing the bone deficiency that often follows conventional extraction. This is particularly important when an implant is planned in the future, as adequate bone volume is essential for successful implant placement. How long after extracting an ankylosed tooth can an implant be placed? In growing patients, implant placement should be deferred until facial growth is complete — typically age 18 to 21. Placing an implant too early in a growing jaw will result in the implant appearing to submerge as the adjacent jaw and teeth continue to grow. In adult patients with completed growth, implant placement can proceed once there is adequate bone volume, usually after any orthodontic space management is complete and the site has healed from extraction. Is ankylosis covered by the NHS? Management of ankylosed deciduous teeth in children — including monitoring, extraction, and decoronation — is available on the NHS where the patient meets IOTN criteria for orthodontic treatment. NHS oral surgery referral covers surgical procedures such as decoronation. For adults with ankylosed permanent teeth requiring space management orthodontics and implant restoration, the orthodontic element may be NHS-eligible in some cases, but implant placement is not routinely available on the NHS and will require private funding. A specialist orthodontist can advise on what is available through each pathway. Explore your options Quick links Not sure where to start? Use these quick links to explore orthodontic treatments, typical costs, and helpful guides that explain what different options involve. Whether you're researching braces or clear aligners, comparing pricing, or just getting a feel for what comes next, you can browse at your own pace and come back when you're ready to request a quote. 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Upload guided photos and get a tailored recommendation for your teeth and bite. [Start Photo Assessment](https://virtualconsultant.online/evaluations/quote) [Find an Orthodontist](https://virtualconsultant.online/locations) Citation details Title Ankylosed Teeth and Orthodontics UK | When a Tooth Cannot Move Publisher Virtual Consultant Online Published 2024-06-01 Updated 2026-09-07 URL [https://staging.virtualconsultant.online/guides/ankylosed-teeth-orthodontics-uk](https://staging.virtualconsultant.online/guides/ankylosed-teeth-orthodontics-uk)