Ankylosis of traumatized permanent incisors: pathogenesis and current approaches to diagnosis and management

Ankylosis is a known complication of replanted or severely intruded permanent incisors and can be diagnosed by the characteristic sound emitted when the tooth is tapped. The ankylosed incisor demonstrates a lack of physiologic mobility and, later, radiographic evidence of replacement resorption. If the patient is pre-adolescent or adolescent at the time of trauma, infraocclusion relative to adjacent teeth will become apparent during jaw growth. Despite considerable knowledge about the pathogenesis of ankylosis garnered from animal studies and observation of human replanted teeth, there is no known treatment to arrest this condition. Management techniques and rehabilitation options for addressing ankylosis and its consequences are supported by little evidence, do not appear to be widely adopted and do not offer any proven long-term benefit. Avulsion and severe intrusion of permanent incisors are rare injuries. Should the decision be made to intervene by replantation or reduction of the intrusion, the clinician must be prepared to diagnose ankylosis, identify its negative consequences and develop treatment plans accordingly.