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Endo note 14 root resorption


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Endo note 14 root resorption

  1. 1. RESORPTION OF TEETH9/7/2009 Endo 14 1
  2. 2. Dental hard tissues are resorbed by multinucleate cells called ODONTOCLASTS or DENTINOCLASTS.They are considered to be same type as osteoclasts because they possess the same ultra structure and histochemical characteristics.However, dentinoclasts or odontoclasts may contain fewer nuclei than osteoclasts. 9/7/2009 Endo 14 2
  3. 3. Classification:1. Physiological2. Pathologicala) External root resorption a.1) Resorption due to trauma-surface , inflammatory and replacement resorption a.2) Resorption due to pulp or apical pathology a.3) Resorption due to pressureb) Internal root resorptionc) Idiopathic root resorptionRecently, a clinical oriented classification has been developed 9/7/2009 Endo 14 3
  4. 4. This new classification is based on two requirements, namely- *injury to protective tissues: chemically or mechanically *stimulation: by infection or pressureInjury is related to non mineralized tissue covering the external surface of the root-ie., pre cementum or internal surface of the root canal-ie., pre dentine. 9/7/2009 Endo 14 4
  5. 5. Injury:Mechanical- dental trauma, surgical procedures, excessive pressure from tumours or impacted teethChemical-bleaching with 30% H2O2Following injury denuded mineralized tissue become colonized by multinucleated cells which initiate the resorption process.However, without stimulation, resorption process end spontaneously and reparative changes occur.Therefore, continuation of the resorption process depend on continuous stimulation by either pressure or infection 9/7/2009 Endo 14 5
  6. 6. Present classification is based on different stimulation factors.It is clinically oriented as the resorption process can be reversed by removing the stimulation factor.Classification1. Pulpal infection root resorption2. Periodontal infection root resorption3. Orthodontic pressure ,, ,,4. Impacted tooth/tumour ,, ,,5. Ankylotic root resorption9/7/2009 Endo 14 6
  7. 7. Pulpal infection root resorption*most common stimulation factor*following injury to pre cementum or pre dentine inflammatory process within peri radicular or pulpal tissue initiate external or internal resorption*radiolucency is observed in the external root surface of dentine & bone, or in the internal root canal dentinal wall9/7/2009 Endo 14 7
  8. 8. Treatment:Internal resorption- pulptectomy: to remove granulation tissue/ blood supply of resorbing cellsExternal resorption- pulptectomy: critical to remove bacterial stimulation from dentinal tubules using calcium hydroxide. 9/7/2009 Endo 14 8
  9. 9. Periodontal infection root resorption*external root resorption may occur apical to the epithelial attachment, followed by bacterial stimulation originating from periodontal sulcus.*injury may be caused by dental trauma, bleaching agents, orthodontic treatment or periodontal procedures*bacteria penetrate the patent dentinal tubules coronal to epithelial attachment and exist apical to ,, ,, .9/7/2009 Endo 14 9
  10. 10. *radiologically, seen as a single resorption lacuna (radiolucency) at the crestal bone level.*treatment: As long term bacterial removal from the periodontal sulcus is not practical, effective therapy is to expose the resorptive lacunae orthodontically or surgically to remove granulation tissue followed by restoration with composite. Endodontic therapy is only necessary if the resorption process extend in to pulp.9/7/2009 Endo 14 10
  11. 11. Orthodontic pressure resorption*pressure applied to roots during tooth movement can cause apical root resorption. Continuous pressure stimulate resorbing cells of the apical third of the root, leading to shortening of the root.*teeth are usually vital if undue pressure is not applied*located at apical one third of the root, but no signs of radiolucency can be observed.9/7/2009 Endo 14 11
  12. 12. *treatment: removal of the pressure source is usually sufficient. Operative procedures are not necessary. 9/7/2009 Endo 14 12
  13. 13. Impacted tooth/ tumour pressure resorption*impacted tooth pressure resorption can be observed during eruption of the permanent dentition Max 3….Max2, Man 3….Man 2.*tumours impinging on the tooth roots can cause pressure resorption. Tumours that produce resorption are slow growing lesions as ameloblastoma, giant cell tumours ect.,* usually, asymptomatic with vital pulps9/7/2009 Endo 14 13
  14. 14. *radiologically, resorption area is located adjacent to the stimulation factor. Radiolucencies are not observed as infection is not involved. The site is filled with stimulation factor.*treatment:surgery to remove the stimulation factor9/7/2009 Endo 14 14
  15. 15. Ankylotic root resorption*in severe traumatic injuries eg intrusive luxation or avulsion injury to the tooth surface may be large so that healing with cementum is not possible and the bone comes in contact with root surface without periodontal ligament. This is known as dento-alveolar ankylosis.*Although, there is no stimulation factor and the process proceeds as a result of direct bone attachment to dentine, the term ankylotic resorption is used.9/7/2009 Endo 14 15
  16. 16. *radiologically, the resorption lacunae are filled with bone and the periodontal ligament space is missing. No radiolucent area is observed.*treatment: as there is no stimulation to remove, no predictable treatment is available.Best approach is to minimize periodontal ligament damage.9/7/2009 Endo 14 16
  17. 17. Invasive cervical resorptionRelatively uncommon form of external root resorption.Characterized by cervical location and invasive nature, resorptive process can lead to loss of tooth structureEtiology is poorly understood, however, intracoronal bleaching, orthodontic tooth movement, trauma ect., are considered as predisposing factors. 9/7/2009 Endo 14 17
  18. 18. • ClassificationClass 1: small invasive resorptive lesion near the cervical area with shallow penetration in to dentineClass 2: well defined invasive resorptive area that has penetrated close to coronal pulp but shows no extension in to radicular pulp.Class 3: deeper invasion of both coronal and coronal third of radicular dentine by resorptive processClass 4: large resorptive focus that has extended beyond coronal third of root 9/7/2009 Endo 14 18
  19. 19. Osteoclast*derived from monocyte macrophage haemopoietic lineage.*cell responsible for bone resorption*multinucleated cell containing 4-20 nuclei*usually found in Howship’s lacunae*ultrastructure: contain numerous golgi complexes around each nucleus and mitochondria and transport vesicles loaded with lysosomal enzymes*most characteristic feature is the presence of the ruffled border and the sealing attachment 9/7/2009 Endo 14 19
  20. 20. *osteoclasts synthesize and secrete tartarate resistant acid phosphatase and cathepsin Kinto the extracellular bone resorbing compartment. In addition, cells also secrete MMP 9 & 13 which stimulate pre-osteoclast migration and bone matrix digestion.*attachment of osteoclast to bone surface is essential for bone resorption and involves integrins.*thereafter, avb3 binding activates cytoskeletal reorganization within the cell including cell spreading and polorization. 9/7/2009 Endo 14 20
  21. 21. stem cell PU1 Osteoclast progenitor OPG/RANKL Differentiationmacrophage RANK Fusion Polarization Activation 9/7/2009 Endo 14 21