Root Resorption


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Clinical Endodontics
Fifth Year

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Root Resorption

  2. 2. • Root resorption is a condition associated with either a physiologic or a pathologic process resulting in a loss of dentin, cementum and/or bone • It may be initiated in the periodontium and affect initially the external surfaces of the tooth (external resorption) or it may start within the pulp space affecting primarily the internal dentin surfaces (internal resorption).
  3. 3. • With the exception of minor, transient surface resorption, loss of tooth structure is irreversible. • Treatment, when successful, can only arrest the process and when less successful, slow down resorption. • If not diagnosed and treated, that can lead to tooth extraction.
  4. 4. Etiology of Root resorptions PHYSIOLOGIC PATHOLOGIC LOCAL CAUSES: SYSTEMIC Dental trauma Pagets disease PA pathology Herpes Zoster infection Cysts Hormonal imbalance: Tumours Hyperparathyroidism Excessive Mechanical Hypophosphataemia, forces Hypothyroidism, Impacted teeth Hypopituitarism Intracoronal Bleaching Hyperpituitarism IDIOPATHIC
  5. 5. • The etiology of root resorption requires two phases: Injury and Stimulation • The injury is similar to several types of root resorption • Injury is related to the non-mineralized tissues covering the external surface of the root, the precementum, or internal surface of the root canal, the predentin.
  6. 6. • Internal resorption • External resorption :  Surface  Inflammatory  Replacement resorption • Invasive resorption • Pressure resorption • Idiopathic resorption
  7. 7. A clinical-related classification of root resorption that will assist in diagnosis and treatment of the pathological process. Pulpal infection root resorption Periodontal infection root resorption Orthodontic pressure root resorption Impacted tooth or tumor pressure root resorption Ankylotic root resorption
  8. 8. INTERNAL RESORPTION: • Internal resorption is relatively rare in occurrence • It is caused by trauma  Transient variety involves only loss of odontoblasts and predentin and therefore is shallow. It is self limiting and is repaired presumably with new hard tissue.  Progressive internal resorption continues from the point where dentin is exposed after the loss of odontoblasts and predentin. .
  9. 9.  The stimulus for resorption is often provided by infected, necrotic pulp tissue coronal to the resorptive lesion.  The resorptive process requires vital tissue, hence although clinically the pulp space coronal to the resorptive defect may have necrotic tissue, the rest, including the area of resorption , may contain vital tissue
  10. 10. • Resorption usually occurs till the necrotic process overtakes the vital tissue in the remainder of the pulp space, thus depriving the tissue of needed blood supply, at which time the internal resorptive process ceases. • Recognition is both clinically as well as by radiographic means. • Clinical finding – Pink spot. If the resorption involves the crown , a pink area may show through the enamel • No specific symptoms such as pain
  11. 11. P I N K S P O T
  12. 12. Radiographs – OUTLINE OF LESION: Sharply outlined appearance (than in external resorption). OUTLINE OF ROOT CANAL: Outline of the root canal is lost. CHANGE IN ANGULATION: Radiographs taken from different angles tend to show the resorptive lesion in the central location.
  13. 13. Treatment: root canal therapy
  14. 14. EXTERNAL ROOT RESORPTION: Surface resorption: • It is associated with trauma to teeth in which the injury damages cementum and cementoblasts. • The traumatic event maybe avulsion, luxation, orthodontic forces or periodontal infections. • Maybe transient or progressive. • Surface resorption is not detected radiographically and can be observed only histologically
  15. 15. Inflammatory resorption: can be of pulpal or periodontal origin Four factors that contribute to the development of IERR. • Inury to the PDL: Most frequently this occurs when the ligament is torn, such as in avulsions and luxations • Initiation of surface resorption: damage to the root surface leads to the surface resorption of cementum. For the process to continue, the surface resorption must expose the subjacent dentinal tubules.
  16. 16. • Communication with the necrotic pulp tissue or an inflammatory zone favouring bacteria: if the traumatic event has resulted in significant reduction or complete destruction of pulpal blood flow → necrosis → infection. • Patency of dentinal tubules: larger the diameter of the tubules the more rapid is the resorption
  17. 17. • Diagnosis • History of trauma: maybe recent or may have been several years earlier. • The onset and pace of resorption depends on the pulpal condition and the patency of the communicating dentinal tubules. • Clinical findings: based on the results of examination procedures such as percussion, palpation, mobility evaluation and periodontal probing.. in most cases the pulp is either necrotic or irreversibly involved. Sensitivity to percussion may be due to the periradicular inflammation; surrounding alveolar bone maybe sensitive to palpation because of osteitis
  18. 18. • Radiographic evidence will demonstrate loss of both tooth structure and adjacent alveolar bone. • Not so sharply outlined appearance (than in internal resorption). • Outline of the root canal is seen. • Radiographs taken from different angles tend to move the resorptive lesion
  19. 19. Treatment: • Removal or reduction of the source of infection • It has been recommended to include a calcium hydroxide phase to the root canal treatment to enhance the outcome
  20. 20. • Calcium hydroxide for 6-24 months is the intracanal medicament of choice for the treatment of ERR • Calcium hydroxide  has strong anti-bacterial effect  also increases the pH of dentin →inhibits the activity of osteoclastic acid hydrolases in the periodontal tissues and activates the alkaline phosphatases
  21. 21. Replacement resorption / Ankylotic root resorption : • When tooth structure is replaced with bone that fuses with dentin, it is termed replacement resorption. • It occurs frequently as a result of complications following avulsions in which the PDL dries and loses its vitality • Ankylosis may be transient or progressive.
  22. 22. Transient type : • Less than 20% of the root surface becomes ankylosed. In such cases reversal may occur, resulting in re-establishment of a PDL connection. Progressive type : • The tooth structure is gradually resorbed and replaced with bone. • Histologically there is a direct fusion between the bone and dentin.
  23. 23. Clinically several problems are noted :  Infra-occlusion  Incomplete alveolar process development ( if the patient is young)  Prevention of, normal mesial drift.
  24. 24. Diagnosis: Clinical -: Lack of mobility and high pitched metallic sound when percussed.In such cases more than 20% of bone has been ankylosed. If less than 20%, then it cannot be reliably detected clinically. Radiographic: loss of PDL space with replacement by bone in association with an uneven contour of the root
  25. 25. Treatment: • There is currently no treatment for replacement resorption. • Limiting the damage to the PDL is the most important factor in avoiding the development of ankylosis. • It maybe possible to slow down the resorptive process by treating the root surface with a fluoride and / tetracycline solution prior to replantation • Functional stimulation and flexible rather than rigid splinting of the tooth during the healing phase has been shown to reduce the area of ankylosis
  26. 26. INVASIVE RESORPTION: A type of resorption that involves the cervical area of the tooth . commonly called Invasive cervical resorption. “ Late external resorption” : as this resorption may not become clinically evident until years after the original injury. Other terminologies used are • Odontoclastoma • Peripheral cervical resorption • Cervical external resorption • Extra canal invasive resorption • Supraosseous Extra canal invasive resorption
  27. 27. • Invasive cervical resorption is initiated from the cells in the periodontal ligament and is characterized by the ingrowth into the cervical area of the tooth by fibro-vascular tissue which slowly resorbs enamel, cementum and dentin • A likely pre-requisite is the deficiency in the normally protective Cementum-cementoid layer / Precementum, either due to congenital absence or due to damage caused by physical or chemical trauma
  28. 28. • Initially the resorptive tissue is devoid of inflammatory cells indicating a non-bacterial etiology. Secondary bacterial invasion at a later stage will elicit a normal inflammatory response in the associated periodontal or pulpal tissue. • The pulp is usually protected until late in the process by a thin layer of dentine and Predentin
  29. 29. Causes: trauma, orthodontic tooth movement, dento alveolar surgery, secondary bone grafting of alveolar clefts, Periodontal treatment, intracoronal bleaching of teeth, and in some cases idiopathic
  30. 30. Diagnosis: • Clinically a pink spot maybe observed cervically . • The resorptive lacunae can be probed through the gingival sulcus and maybe observed to extend coronally under the enamel. • The exposed dentin is hard(unlike carious) and the lacunae contains vascular tissue
  31. 31. • Class 1: a small invasive resorptive lesion near the cervical area with shallow penetration into dentin • Class2: a well defined lesion that has penetrated close to the coronal pulp chamber but shows little or no extension into radicular dentin • Class 3: a deeper invasion into coronal dentin and also extending at least to the coronal 3rd of the root • Class 4: a large lesion that has extended beyond the coronal third of the root canal, and may involve almost half the root
  32. 32. • Radiographs : • Lesion may have smooth or a rough outline. Because the adjacent bone is often involved the resorption may often give appearance of an infrabony pocket. • The root canal outline is intact. • The appearance varies from an irregular moth-eaten appearance to a more regular radiolucency which may resemble caries
  33. 33. • Successful treatment relies upon the complete removal or inactivation of the resorptive tissue. This is difficult to obtain in more advanced lesions. • In most cases, surgery is necessary to gain access to the resorptive defect and often may cause loss of bone and periodontal attachment.
  34. 34. • Topical application of a 90% aqueous solution of trichloracetic acid, curettage and sealing of the defect has proved successful in most cases. • Large defects associated with advanced stages of this condition have a poor prognosis. • Replacement resorption or ankylosis occurs following extensive necrosis of the periodontal ligament with formation of bone onto a denuded area of the root surface
  35. 35. PRESSURE RESORPTION: • Various pressures can lead to resorption. Some examples include orthodontic forces, excessive occlusal forces, pressure from impacted or supernumerary teeth and pressure from tumors and cysts.. • Two factors are associated with pressure resorption:  pulp is usually not involved, at least not initially  resorption tends to be arrested when the cause is removed.
  36. 36. IDIOPATHIC RESORPTION: When no etiologic factor can be identified, root resorption has been classified as idiopathic