Ankylosis of teeth


Molar I reinclusion
Dental ankylosis
Secondary retention of permanent molars
Abnormal fusion of dental cementum with alveolar bone


A rare genetic disorder where the teeth fuse to the bone which can prevent them from erupting.


  • Congenital absence of teeth
  • Congenital absence of many teeth
  • Abnormal dental position
  • Abnormal tooth enamel
  • Dental caries
  • Reduced number of teeth


Ankylosis of deciduous teeth ("submerged teeth") may rarely occur. The most commonly affected tooth is the mandibular (lower) second deciduous molar. Partial root resorption first occurs and then the tooth fuses to the bone. This prevents normal exfoliation of the deciduous tooth and typically causes impaction of the permanent successor tooth. As growth of the alveolar bone continues and the adjacent permanent teeth erupt, the ankylosed deciduous tooth appears to submerge into the bone, although in reality it has not changed position. Treatment is by extraction of the involved tooth, to prevent malocclusion, periodontal disturbance or dental caries.


  • NIH