Endodontic Failures and Mishaps


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A detailed presentation on Endodontic failures starting from the basics in case selection to final prosthesis. Good for Post Graduates and Under Graduates.

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  • For instance, under conditions of nitrogen starvation, the activation of the Ntr gene system enables bacteria that require ammonia as a nitrogen source to scavenge even small traces of ammonia. Under high concentration of ammonia, the Ntr gene system is uncoupled.Some facultative bacteria may activate the Arc system (aerobic respiration regulatory), composed of the arcA and arcB genes, under conditions of low concentrations of molecular oxygen. As a consequence, metabolic pathways are activated, which permit the utilization of alternate terminal electron acceptors for respiratory metabolism so that a shift can occur from aerobic to anaerobic metabolism.
  • Endodontic Failures and Mishaps

    1. 1. Dr. Abhishek John Samuel III yr MDS Dept of Conservative Dentisty & Endodontics SRDC
    2. 2. Schilder’s Objectives of RCT  1. The root canal preparation should develop a continuously tapering cone  2. Decreasing cross sectional diameters at every point apically and increasing at each point as the access cavity is approached  3. In multiple planes which introduces the concept of ‘flow’  4. Do not transport the foramen  5. The apical opening should be kept as small as practical in all cases.
    3. 3. Objectives of RCT  SUCCESS IS DEFINED BY THE GOALS ESTABLISHED TO BE ACHIEVED  The ultimate goal of Endodontic treatment is to maintain or restore 1. the health of periapical tissues and 2. the tooth.  The treatment of teeth with irreversibly inflamed pulps is essentially prophylactic.  But in cases or infected necrotic pulp – established infection – apical periodontitis.  In such cases focus is on – 1) Prevention of introduction of new microorganisms  2) Elimination of those colonizing the root canal.
    4. 4. The virtual and REAL goal!  Given the complex anatomy of the RCS,  Even with the multitude of instruments and materials available  Fulfilling 100% of the goals is virtually impossible.  Therefor the Realistic Goal is to reduce bacterial populations to a level below that necessary to induce or sustain periapical disease.  Accomplish this by an Evidence- based antibacterial protocol  Clinician’s Aim!
    5. 5.  Root canal treatment usually fails when treatment falls short of acceptable standards (Seltzer et al. 1963, Engström et al. 1964, Sjögren 1996, Sundqvist et al.1998)  Persistence of microbial infection in the root canal system and/or the periradicular area (Nair et al. 1990a, Lin et al. 1992).
    6. 6. Desirable End point  The apical constriction is the narrowest point of the apical root canal - the ideal apical end point for RC obturation.  Apex locators, in reality detect a point somewhere between the apical constriction and the major apical foramen  The radiographic apex is the most apical point of the root as seen on a radiograph. This does not necessarily form the apical foramen.
    7. 7.  There are some cases in which the treatment has followed the highest technical standards and yet failure results. Scientific evidence indicates that some factors may be associated with the unsatisfactory outcome of well-treated cases.  They include 1. microbial factors, (comprising extraradicular and/or intraradicular infections)  And 2.intrinsic or extrinsic nonmicrobial factors. (Nair et al. 1990a, Nair et al. 1990b, Lin et al. 1992, Nair et al. 1993, Sjögren 1996, Nair et al. 1999)
    8. 8.  Sundqvist (1976) confirmed the important role of bacteria in periradicular lesions in a study using human teeth, in which bacteria were only found in root canals of pulpless teeth with periradicular bone destruction. [similar to Kakehashi et al. (1965)]  How high the risk of reinfection will be - dependent on the quality of the root filling and the coronal seal (Saunders & Saunders 1994)
    9. 9.  Studies have demonstrated that part of the root canal space often remains untouched during chemomechanical preparation, regardless of the technique and instruments employed (Lin et al. 1991, Siqueira et al. 1997).  A radiograph of a seemingly well-treated root canal does not necessarily ensure the complete cleanliness and/or filling of the root canal system (Kersten et al. 1987)
    10. 10.  If the root canal filling fails to provide a complete seal, seepage of tissue fluids can provide substrate for bacterial growth. (Sundqvist & Figdor 1998, Lopes & Siqueira 1999)  the occurrence of viable microbial cells - in treated teeth with a persistent periradicular lesion indicates that microorganisms derive nutrition, presumably from tissue fluid which can seep into the root canal space (Sjögren 1996, Sundqvist et al. 1998, Molander et al. 1998)
    11. 11.  Regulatory mechanisms – nutrient deprivation.  Predetermined genes – transcription activated under stress!  Ntr Gene (N2)  ArcAB Gene (O2)  Catabolite repressor (Gl)
    12. 12.  Anaerobic bacteria corresponded to 51% of the isolates. Enterococcus faecalis was found in 29% of the cases. - Möller (1966)  Sundqvist et al. (1998) observed a mean of 1.3 bacterial species per canal and 42% of the recovered strains were anaerobic bacteria. E. faecalis was detected in 38% of the infected root canals
    13. 13. Introduction:  In different studies success rate ranges from 54 percent to 95 percent.  The definition of success in RCT is ambiguous - stringent : radiographic and clinical normalcy - lenient : only clinical normalcy
    14. 14. Endodontic treatment outcome  Healed: both clinical and radiographic presentations are normal  Healing: it’s a dynamic process, reduced radiolucency combined with normal clinical presentation  Disease: No change or increase in radiolucency, clinical signs may or may not be present or vice versa
    15. 15. Question?  “How successful is endodontic therapy?” a study was undertaken at the University of Washington School of Dentistry.  91 to 95% of all endodontic treatments have a successful outcome.  Retreatment gives a 50 % chance to a tooth deemed to be a failure.
    16. 16. Sjogren’s study on Success vs. Failures  Sjögren and his associates from Sweden - study of 356 endodontic patients, re-examined 8 to 10 years later, reported a 96% success rate if  - the teeth had vital pulps prior to treatment.  The success rate dropped to 86% if the pulps were necrotic with periradicular lesions.  They dropped still lower to 62% if the teeth had been re- treated.  They concluded by stating that “teeth with pulp necrosis and periradicular lesions and those with periradicular lesions undergoing re-treatment constitute major therapeutic problems…
    17. 17. Failures are broadly categorised under - Apical Percolation 63.47% 1. Operative Errors 15% of the failures (root perforation, 9.61%; broken instrument, 0.96%; and canal grossly overfilled, 3.85%; 2. Faulty case selection 22.12% 3.
    18. 18. Evaluation of success  Success or failures following endodontic therapy could be evaluated from combination of clinical, histopathological and radio graphical criteria.
    19. 19. Clinical evaluation for success  No tenderness to percussion or palpation  Normal tooth mobility  No evidence of subjective discomfort  Tooth having normal form, function and aesthetics  No sign of infection or swelling  No sinus tract or integrated periodontal disease  Minimal to no scarring or discoloration
    20. 20. Radiographic evaluation for success  Normal or slightly thickened periodontal ligament space  Reduction or elimination of previous rarefaction  No evidence of resorption  Normal lamina dura  A dense three dimensional obturation of canal space
    21. 21. Histological evaluation for success  Absence of inflammation  Regeneration of periodontal ligament fibers  Presence of osseous repair  Repair of cementum  Absence of resorption  Repair of previously resorbed areas  Procedure has been successful clinically, yet histologically pulp lesion may present (seltzer et al – 1963)  It should not assumed that following endodontic treatment periapical lesion always resolves.
    22. 22. TREATMENT IS CONSIDERED FAILED IF.  1) Treated tooth is symptomatic or has an abnormal appearance.  2) Soft tissue response abnormally to manual examination. A Radiographic examination of the tooth is usually suggested for the same.
    23. 23. RADIOGRAPHIC The criteria for failure are  1) Development of radiographic rarefaction of periapical area after completion endodontic treatment.  2) in cases, where none has been present before treatment appearance of radiographic rarefaction of periapical area after endodontic treatment.  3) The increase in size of area of rarefaction after completion of root canal treatment. (Bender et al, 1964 ,Luebike et al 1964 ,Seltzer et al 1963 )
    24. 24. Factors affecting success or failure of endodontic therapy in every case  Diagnosis and the treatment planning  Radiographic interpretation  Anatomy of the tooth and root canal system  Debridement of the root canal space
    25. 25. 1) Incorrect diagnosis  It can be result of misdiagnosis, poor case selection, & poor prognosis.  Incorrect diagnosis usually results from a misinterpretation or lack of information, either clinical or radiographic.  Errors in case selection are not so easily overcome as operative error  A careful medical history is essential.
    26. 26. 3) Anatomical Variations.  According to Ostrander (1958) such factors as presence of excessively curved canal, excessive root mineralization , impenetrable accessory canal & canal bifurcation near root open may result in endodontic treatment failures.  Problems in cleaning and shaping & incomplete filling of root canals
    27. 27. 4) Poor debridement.  Untreated or inadequate debridement of root canals has a definite relationship to the failure of endodontic treatment (Grossman 1972).  Debridement of root canal reduces the microbial flora, but apparently does not eliminate it (Ingle 1965).
    28. 28. Incomplete debridement of the root canal system  Main objective of root canal therapy→complete elimination of the microorganisms and their byproducts  Poor debridement → residual microorganisms, byproducts and tissue debris → recolonize
    29. 29.  When instrument has been confine to root canal & presumably instrument root have damage the apical pulp stump , chances for repair are enhanced (Strindberg 1956).  Strindberg (1956) found that, even teeth with non-vital pulp. There was lower frequency of failure when canal could not be reamed through apex as compared to these where instrumentation was carried out to or beyond the apex.  Grahnen &Hansson (1961) & Frosteu (1963) even found that failure frequency was greatest in single noted teeth when the canal is apparently easiest to file & ream.  During endodontic treatment, various medications are used as dressing in root canal. Their functions are presumably to eliminate or reduce microbial flora, prevent or lessen pain, reduce inflammation or stimulate repair.  Torreck (1961), Schilder and Amesterdam (1956) have demonstrated irritating potential of many root canal medicament.
    30. 30. Chemical Irritants  Intracanal medicaments and irrigating solution →extruded in the periapical tissues→the prognosis of endodontic treatment ↓  One should take care while Using medicaments to avoid their periapical extrusion
    31. 31. A B C D E F
    32. 32. Factors affecting success or failure of endodontic therapy in every case  Quality and extent of apical seal  Quality of post endodontic restoration (coronal seal, resistance and retention)  Systemic health of the patient  Skill of the operator
    33. 33. Characteristics of Post Systems
    34. 34. Factors affecting success or failure of a particular case  Pulpal and Periodontal status  Size of periapical radiolucency  Canal anatomy  Crown and root fracture Contd.-
    35. 35. Factors affecting success or failure of a particular case  Iatrogenic errors  Extent and quality of the obturation  Quality of the post endodontic restoration  Time of post treatment evaluation
    36. 36. Local Factors causing endodontic failures  Infection  Incomplete debridement of the root canal system  Excessive hemorrhage  Chemical irritants  Iatrogenic errors
    37. 37. Infection  infected and necrotic pulp tissue→main irritant to the periapical tissues  The host parasite relationship、virulence of microorganisms , ability of infected tissues to heal→influence the repair of the periapical tissues  Endo success →debridement
    38. 38. Latest study  Oral Microbiology and Immunology  Volume 19, Issue 2, pages 71–76, April 2004
    39. 39. Micro-organisms Signs & Symptoms (JSR Vol 2(2) – July 2009)- Vivek Rana, Susheel Mansoor  E. faecalis - Previous pain, Tenderness on percussion, odour, wet canal & periapical radiolucency.  F. nucleatum - Tenderness on percussion & mobility.  P. gingivalis - Previous pain, spontaneous pain, Tenderness on percussion, mobility & periapical radiolucency.  T.denticola - Previous pain, Tenderness on percussion, mobility, odour, swelling & periapical radiolucency.  Parvimonas micra- Spontaneous pain, mobility & periapical radiolucency.  Tannerella forsythensis - Spontaneous pain, Tenderness on percussion, mobility, wet canal & periapical radiolucency.  Streptococcus sp. - Previous pain & periapical radiolucency
    40. 40. Excessive hemorrhage  Extirpation of pulp and instrumentation beyond periapical tissues  Local accumulation of the blood→mild inflammation  Extravasated blood cells and fluid:foreign body nidus for bacterial growth
    41. 41. Over instrumentation  Instrumentation beyond apical foramen→PDL and alveolar bone trauma→the prognosis of endodontic treatment ↓
    42. 42. Shortcomings that promote loss of WL  Failure to irrigate frequently and copiously with a tissue dissolving irrigant.  Failure to recapitulate  Failure to radiographically verify the working length.  Malpositioned instrument stops  Failure to record and use stable reference points.  Skipping instrument sizes
    43. 43. Iatrogenic errors  Separated instruments—  Caused by improper or overuse of  instruments and forcing them in curved canals  Prognosis :no much affected in vital pulps poor in necrotic tissue.
    44. 44. Iatrogenic errors  Canal blockage and ledge formation—  Accumulation of dentin chips or tissue debris prevent the instruments to reach its full working length  Ledge formation—straight instruments in curved canals  These lead to bacteria & debris remaining endo failure
    45. 45. Management of debris blockade  Stiff file (15 or above)  Curved in apical 1 to 3 mm at a 30 to 45- degree bend  Rotated till catch obtained  Then in and out winding!
    46. 46. Iatrogenic errors  Perforations—  Lack of knowledge of anatomy of the tooth, attention, misdirection of the instruments  Prognosis:location, time, perforation seal and size  Poor prognosis  remaining infected tissue
    47. 47. Iatrogenic errors Incompletely filled teeth—  Teeth filled more than 2mm short of apex Several studies shown:  poor prognosis—underfillings with necrotic pulps Overfilling of root canals—  Overfilling extending ≧2mm beyond  radiographic apex  Continuous irritation of the periapical  tissues endo failure
    48. 48.  According to Crump (1979), it is not necessary to treat overfill unless clinical symptoms develop. Causes of overfilling:  1. Failure in determine the exact location of the apical foramen.  2. An absence of apical stop or constriction in mature teeth.  2. Incorrect selecting of master cone.  3. Open apices.
    49. 49. Iatrogenic errors Root fractures—  Partial or complete fractures of roots  Prognosis of teeth:vertical root is poor than horizontal fractures Traumatic occlusion –  Cause endo failures because of its effect on periodontium  Missed Canals
    50. 50. Benefits of the Crown Down!
    51. 51. Systemic factors causing endodontic failures  Nutritional deficiencies  Diabetes mellitus  Renal failure  Blood dyscrasias  Hormonal imbalance  Autoimmune disorders  Opportunistic infections  Aging  Long term steroid therapy
    52. 52. Treatment options to be discussed?  Non- surgical root canal re -treatment. (secondary root canal treatment)  Surgical root canal treatment (using endodontic conventional / microsurgical techniques)  Leave alone  Extraction
    53. 53. 7
    54. 54. Case Selection  External root resorption  Coexistent periodontal periradicular lesion  Developing apical cyst, adjacent pulpless tooth  Accessory canal unfilled  Constant trauma  Perforation of the nasal floor. Non-clinical factors  Hysterical  Abusive  Non-compliant  Poor oral hygiene
    55. 55.  Strindberg L Z (1956): - endodontic failure is about six decade old story started by Strindberg by his comprehensive study and has made attempt to answer the basic questions about the success and failure of endodontic treatment.  Jokinen et al (1978), Morse et al (1983) & Pekruhn (1986) - conducted study to assess the success and failure rate of endodontic treatment. Success rate ranged from 53% - 65%.  Grossman et al(1965): - conducted study of 1229 cases treated by student & practitioner , success rate was 91.5% while failure was 8.5%.Divided the causes of endodontic failure in four category i.e. poor diagnosis ,poor prognosis , technical difficulties & careless treatment(197  Torpe, Transtad & Maltzdo: - Described the contribution of overextended access preparation leads to excess reduction of dentin leads to weaking of tooth.  Seltzer s,Sinai & Agust D(1970) : Irritating effect or the micro leakage of materials used` for repair of perforations causes endodontic lesion to develop and subsequent failure of treatment.
    56. 56.  Grossman LI (1972) : Objective of endodontic treatment is complete removal of potential irritant from root canal space , control of infections , shaping of the canal and removal of organic debris is considered as critical requirement of endodontic therapy to do successfully.  Crumps (1979): Has listed several alternatives for differential diagnosis of endodontic failures i.e. perforation, obturation, overfilled, root canal missed, periodontal disease , another tooth and trauma.Szajkiss and Fagger M (1983) : - said that more rigid the criteria of operator in case selection, greater the chances of success, where as treatment of all cases without case selection criteria increases the chances of failures.  Ingle (1985) : - Described causes of endodontic failures into three main groups. Apical perforation, operative errors and errors in case selection.  Kaffe I and Saint Louis (1987) : - Describes that incorrect diagnosis resulted from a misinterpretation or lack of information either clinical or radiographic leads to endodontic treatment in wrong tooth and causes subsequent failures of endodontic treatment
    57. 57. Thank You!