Root resorption


Resorption is the loss of dental hard tissue (cementum and dentine), as a result of odontoclastic action.

External root resorption:

  • Surface resorption: localized small injury to the periodontal ligament due to trauma. Small extent of resorption, shelf limiting with new cementum formed.
  • External inflammatory root resorption: Bowl shaped areas of resorption of both cementum and dentine, accompanied by inflammation of the adjacent periodontal tissue. It is always related to the presence of infected necrotic pulp in the root canal.
  • Pressure resorption: Periodontal ligament and cement stay intact. Caused by different kind of pressure (orthodontic treatment, impacted teeth, tumors). When pressure is removed then resorption stops.
  • External cervical invasive root resorption: Resorptive process below the epithelial attachment of the tooth at the cervical region. Radiographic appearance varies from asymmetrically radiolucency with irregular margins to mottled appearance due to fibro-osseous nature of the lesion. Pulp tissue plays no role in the etiology. Possible predisposing factors: orthodontics, trauma, bleaching, bruxism, surgical procedures.
  • Internal root resorption:

    • It is a pathologic phenomenon characterized by the loss of dentine as a result of clastic cells action and represents expansion of the canal with or without perforation. It occurs in conditions of pulpal inflammation.



Internal root resorption in 26.

External root-resorption caused by impacted premolar. Images showing intimate relationship between the premolar and molar. Severe root resorption in the molar and destruction of the buccal cortex.

Cervical external resorption in tooth 11.

Different cases of internal root resorption.

Different cases of external root resorption.

Central incisor showing external root resorption caused by impacted canine.

Root resorption associated with orthodontic treatment.