Dental ankylosis is a rare disorder characterized by the fusion of the tooth to the bone, preventing both eruption and orthodontic movement. The prevalence is unknown. The periodontal ligament is obliterated by a 'bony bridge' and the tooth root is fused to the alveolar bone. Dental ankylosis can affect both primary and permanent teeth, may occur at any time during eruption and can lead to submergence. Permanent molars are less frequently affected than deciduous molars. Varying numbers of teeth may be affected. After eruption, it halts any adaptive changes. In a growing child, an ankylosed tooth appears to 'submerge' as adjacent unaffected teeth and alveolar bone continue their normal pattern of growth occlusally. The disorder may result in loss of the retained molar and neighboring teeth due to caries and periodontal disease, and in deformation of the facial skeleton (reduction in the height of the lower face, relative mandibular prognathism, posterior open bite). The major characteristic of a secondarily retained molar is infraocclusion that may result in malocclusion. Occasionally, dental ankylosis may be associated with fifth finger clinodactyly. Etiology remains uncertain but a genetic predisposition to ankylosis with autosomal dominant inheritance has been suggested. Familial occurrence has been shown in several families. Trauma, inflammation or infection may play a causative role. Clinical examination and X-ray are the main diagnostic methods for detecting ankylosis. The recommended management includes removing the ankylosed tooth to ensure development and eruption of the permanent teeth, and surgery to expose, protect, or reposition the emerging tooth.
Last update: January 2008