Ankylosis (Dental)
Pronunciation: ang-kih-LOH-sis
Fusion of the tooth root cementum and/or dentine directly to the surrounding alveolar bone, with loss of the intervening periodontal ligament space, visible radiographically as obliteration of the PDL space.
Full Definition
Dental ankylosis occurs when the normal periodontal ligament is replaced by a direct bony union between the root and the alveolar bone, most commonly following dental trauma, particularly replantation or intrusion injuries. Radiographically, it is identified by the absence or interruption of the normal radiolucent periodontal ligament space, though early ankylosis may be radiographically undetectable. Clinically, an ankylosed tooth produces a high, metallic percussion note. In growing patients, ankylosis leads to infraocclusion (submergence) of the affected tooth as the surrounding alveolar bone continues to develop. Editors should take care not to confuse 'ankylosis' with 'fusion,' which describes the union of two adjacent teeth.
Usage
Usage note: In the context of dental trauma, ankylosis and replacement resorption describe a continuous pathological process; ankylosis is the initial finding, replacement resorption the radiographic consequence over time. Clarify the stage when editing trauma case reports.
In Context
- "Follow-up periapical radiographs taken 12 months post-replantation showed obliteration of the periodontal ligament space, consistent with ankylosis." — Dental trauma follow-up report
- "Infraocclusion of the lower left first primary molar was attributed to ankylosis, confirmed radiographically by the absence of the PDL space." — Paediatric dental case note