Success and failures in Endodontics

Having thorough knowledge of the factors affecting success and failure in Endodontics helps to overcome some of the common mistakes in practice.

1. Guided by: Dr Hemant vagarali SUCCESS AND FAILURES IN ENDODONTICS presented by: Dr sahana umesh

2. CONTENTS Introduction Endodontic treatment outcome Evaluation of success of RCT Clinical Radiographic Histological Causes of endodontic failures Local factors affecting success or failure Infection Excessive haemorrhage Incomplete debridement 2

3. Iatrogenic errors Chemical irritants Systemic factors affecting success or failure Factors to be considered before retreatment Factors affecting prognosis of endodontic treatment Contraindications for endodontic retreatment Problems of endodontic retreatment Treatment options Conclusion References 3

4. INTRODUCTION Success is defined by goals established to be achieved, so the goal of endodontic treatment is to heal or prevent the disease. The definition of success of RCT is ambiguous : Stringent: Radiographic and clinical normalcy Lenient: Clinical normalcy In different studies success rate ranges from 54-95% for RCT. Non surgical retreatment showed a higher rate of success(83%) compared with endodontic surgery (71.8%) 4

5. Communication with patients can be improved by replacing the value-laden terms ‘‘success’’ and ‘‘failure’’ with neutral expressions: ‘‘chance of healing’’ ‘‘risk of inflammation’’ Avoid the terms ‘‘success’’ and ‘‘failure’’ in defining the outcome of endodontic treatment 5

6. ENDODONTIC TReATMENT OUTCOME Aim of endodontic treatment is to prevent or cure apical periodontitis Healed: Both clinical and radiographic presentations are normal Healing: It is a dynamic process, reduced radiolucency combined with normal clinical presentation Not healed: No change or increase in radiolucency, clinical signs may or may not be present or vice versa. 4 year follow up Immediate post op 3 years 6 years 6

7. Dynamics of healing: The potential of teeth to remain free of apical periodontitis after nonsurgical endodontic treatment is 93–98%. The signs of healing are evident within the first year after treatment in nearly 90% of the cases Rud et al. introduced a classification for outcome assessment after apical surgery that referred to healing: Complete Incomplete Uncertain Unsatisfactory 7

8. Suggested Clinical Approaches Healed: Advised to monitor coronal restorations periodically. Healing: Regular clinical and radiographic check-ups (every 6 months to 1 year). During this period, it is imperative to monitor the coronal restoration to ensure coronal seal and prevent possible fractures. Not healed: Advised to undergo non-surgical or surgical retreatment or extraction. The decision is based on local and general factors 8

9. EVALUATION OF SUCCESS OF RCT 9

10. Assessment of radiographic healing 10

11. Radiographic considerations Who is reading the radiograph? Who performed the treatment? Angulations, exposure and processing settings Time of recall Physical and emotional condition of the operator Patient-clinician relationship 11

12. Treatment outcome studies Ingle & Beveridge undergraduate students at the University of Washington were capable of obtaining 95% success When a carefully followed course of therapy is instituted; little opportunity to deviate from predetermined patterns of therapy- results are strongly in favor of success Strindberg reported on degree of success, criteria: the point to which the canal was filled whether past the radiographic apex, exactly to it, or short of it. All types, responded with success more than 90% of the time, teeth filled slightly short of the apex had the highest ratio of success. 12

13. Washington study To evaluate endodontically treated teeth to determine their rate of success, rate of failure, causes of failure Analysis of the failures in pilot study led to modifications in technique & treatment Improvements in treatment are reflected in the improvement in success, which increased to 94.45% from a former success rate of 91.10% 95% of all endodontically treated teeth were successful 13

14. Even with the limited number of patients in the pilot study, the causes of failure became apparent. Clinical techniques were then changed in an effort to overcome failure  Patients were recalled for follow-up at 6 months, 1 year, 2 years, and 5 years 14

15. Radiographs were carefully evaluated for improvement or lack of improvement Success group: Decided periradicular improvement & those with continuing periradicular health Failures: Teeth that initially demonstrated periradicular damage and that had not improved, as well as those that had deteriorated since treatment 15

16. 2- Year Recall Analysis 1229/ 3678: recall rate of 33.41% Before improvements instituted: 91.10% success rate— 104 failures of 1,067 cases After these improvements were instituted, the success rate rose to 94.45%—9 failures of 162 cases. 16

17. Criticism against the Washington study Only a radiographic study. Histologic evaluation is a much more accurate method of determining if inflammation remains at the apex than radiologic evidence B ut biopsy: impractical in patients 26% of the teeth with no radiolucencies showed chronic inflammation histologically - Walton Since histologic evaluation is impractical: comfort and function & the radiographic findings were considered in the Washington study 17

18. Temple university study 95.2% success rate at the end of 1 year with 458 canals filled by the gutta-percha Vital inflamed pulps: more success (98.2%) than teeth with nonvital pulps (93.1%) Less success with short-filled canals (71.1%) than with flush-filled or overfilled canals (100%) 18

19. Sjogren et al. from sweden Remarkable study of 356 endodontic patients, re-examined 8 to 10 years later 96% success rate if the teeth had vital pulps prior to treatment 86% if the pulps were necrotic & the teeth had periradicular lesions 62% if the teeth had been re-treated Direct correlation between success & the point of termination of the root filling 19

20. Outcome definition as uncertain, questionable, doubtful or improved Originally introduced to imply uncertainty of the outcome & also to define improved outcomes Strictly: cases that could not be assessed because of insufficient radiographic information and thus were not included in either the successful or unsuccessful outcome categories Same terms describe cases with a decrease in size of the radiolucencies & considered either as a successful or as an uncertain outcome for nonsurgical treatment & apical surgery This modified classification lowered the failure rate in comparison with the strict classification 20

21. Causes of endodontic failures 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 Asepsis of treatment regimen Quality and extent of apical seal Quality of post endodontic restoration Systemic health of the patient Skill of the operator 21

22. Pulpal status Periodontal status Size of periapical radiolucency  Canal anatomy like degree of canal calcification, presence of accessory or lateral canals, resorption, degree of curvature of canal Crown and root fracture Iatrogenic errors Occlusal discrepancies Extent and quality of the obturation Quality of the post endodontic restoration Time of post-treatment evaluation Factors affecting success or failure of a particular case : 22

23. Local factors affecting success or failure 23

24. According to Rhodes JS Endodontic failure comprises: Biological failings (infection) Cysts Root fracture Incorrect diagnosis and primary treatment Foreign body reactions Healing with scar Neuropathic problems Economic constraints 24

25. Infection Commonest reason for failure: microbial infection Infected tissues and necrotic pulp are main irritants to periapical tissues Host-parasite relationship, virulence of microorganisms and ability of infected tissues to heal in the presence of microorganisms are the main factors which influence the repair of the periapical tissues 25

26. If apical seal or coronal restorations are not optimal reinfection of root canal can occur Microorganisms & their byproducts- isolated from the RC system & the external surface of the root have been reported in failed cases Microbes persisted following a previous attempt at RCT or gained access through coronal microleakage 26

27. Causes of Persistent periapical periodontitis MICROBIAL CAUSES Intra-radicular Infection Extra-radicular Infection NON MICROBIAL CAUSES Cystic apical periodontitis Cholesterol crystals Foreign bodies Gutta percha Other plant materials/ foreign materials 27

28. The apical portion of the root canal system can contain bacteria & necrotic tissue substrate even following chemomechanical preparation If the resultant microbial ecosystem is amenable to bacterial survival, a lesion may not heal 28 Intra-radicular Infection

29. The radiographic appearance of a RC filling does not give an indication of biological status A satisfactory radiographic result could be failing biologically Bacterial regulatory systems: survive periods of starvation or nutrient depletion Bacteria may not be completely eliminated after thorough cleaning, shaping & disinfection Moreover, when obturation is postponed, bacteria may be able to recolonize in the canal 29

30. No preparation technique can totally eliminate the intracanal irritants, & a “critical amount” can sustain periradicular inflammation Gutta-percha root canal fillings do not resist salivary contamination-“long term prognosis of treatment seems to correlate directly with the quality of the coronal seal.” Irritants: infected dentin chips, is packed at the apex or pushed through the apex Periapical tissue could become colonized: By periodontal contamination the virulence of the resistant bacteria Extrusion by overaggressive instrument action 30

31. Organisms survive in periradicular lesions: - Actinomyces Peptostreptococcus Propionibacterium Prevotella Porphyromonas Staphylococcus Pseudomonas aeruginosa Barnett , stated ‘Pseudomonas refractory periradicular infection could be “cured” only by heavy doses of metronidazole following the failure of re-treatment and apicoectomy 31

32. Bacterial infection: the major cause of persistent periapical inflammation following RCT Technical failings that may predispose RC system to inadequate disinfection: Poor aseptic technique Inability to prepare the canal to length Missed canals Procedural errors Poor obturation Poor restoration and coronal microleakage Resistant bacteria. 32

33. Poor aseptic techniques The majority of RCT is carried out without a rubber dam BENEFITS prevention of microbial contamination the safe use of sodium hypochlorite airway protection retraction of the soft tissues unimpeded vision, which is useful with magnification quicker & more pleasant treatment reduction of microbial aerosol allows the operative field to be dried. 33

34. Failure to achieve patency during preparation: inadequate penetration Persistent infection & endodontic failure Apical 3 mm of a RC- the highest percentage of lateral canals & deltas If mechanical preparation & consequently irrigant penetration: 2–3 mm short of the constriction, the hypothetical length of canal that has not been disinfected could be as great as 6–7 mm Inability to Prepare to length 34

35. Missed canals Aberrant or unusual anatomy: considered in retreatment cases If a root-filled tooth appears satisfactory from a radiographic perspective but is still symptomatic, a missed canal could be suspected The clinician must be aware of normal root canal anatomy before re-entering a RC treated tooth and be prepared for added complexity in retreatment cases 35

36. Poor coronal restoration Coronal restoration: prevent ingress of bacteria into the internal environment & assists in providing a total seal Good RCT with good coronal restoration achieves the best outcome leaking restorations & recurrent caries may compromise the effectiveness of cleaning and shaping: Microleakage Important to achieve an effective seal with a rubber dam to prevent salivary contamination & reinfection during root canal preparation 36

37. Resistant bacteria The microbiological flora in failing root-treated teeth: different from that of an untreated canal Infected untreated canals: mixed infection in which Gram-negative anaerobic rods predominate Failed root-treated canals may only have 1–2 species of generally Gram-positive bacteria 37

38. Microbial flora of rc treated teeth Predominantly Gram-positive cocci, rods & filaments Species belonging to the genera Actinomyces, Enterococcus & Propionibacterium Enterococcus faecalis : it is rarely found in infected but untreated root canals Resistant to most of the intracanal medicaments & can tolerate a pH up to 11.5 Grow as mono infection in treated canals in the absence of synergistic support from other bacteria But its presence: not universal 38

39. E.Faecalis Sundqvist et al : Enterococcus faecalis- 38% of failing canals Increased proportions of E. faecalis in teeth lacking adequate seal during treatment E. faecalis enters the canal during treatment. Strains of E. faecalis have shown resistance: Ca(OH) 2 Yeast-like : Candida species- resistant to the most commonly deployed ICM 39

40. Characteristics of E.faecalis Gram positive cocci: singly, in pairs or as short chains Facultative anaerobes, possessing the ability to grow in the presence or absence of oxygen Enterococci can grow at 100ºC and 450ºC at pH 9.6 in 6.5% NaCl broth and survive at 600ºC for 30 minutes (Sherman, 1937) Survival in root canal infections, where nutrients are scarce & there are limited means of escape from root canal medicaments 23 enterococci species & they are divided into 5 groups based on their interaction with mannitol, sorbose & arginine 40

41. Survival of E.faecalis E. faecalis is less dependent upon virulence factors It has the ability to survive & persist as a pathogen in root canals of teeth ( Rocas et al. 2000) Antibiotic resistance genes is from other microbes or by spontaneous mutation (Mundy et al. 2000) Presence of serine protease & collagen binding protein help in the invasion of E.faecalis into the dentinal tubules (Hubble et al. 2003) 41

42. Alkaline tolerance due to cell wall associated proton pump: resistant to the antimicrobial effect of Ca(OH) 2 ( Fabricus et al.1982; Tansiverdi et al. 1997) Forms biofilm that helps it resist destruction: 1000 times more resistance to phagocytosis, antibodies & antimicrobials than (Chavez De Paz Le et al. 2003) 42

43. Eradication of E.faecalis Sodium hypochlorite effective against existence as a biofilm ( Distel et al., 2002) MTAD ( Abdullah M et al,2005) Erythromycin mixed with Ca(OH) 2 against monoinfections of enterococci ( Shabahang and Torabinejab , 2003) Chlorhexidine better antimicrobial action against E. faecalis ( Basrani et al., 2002) Activity of sealers: Roth 811 greatest antimicrobial activity against E.faecalis Nanometric bioactive glass 45s5, the killing efficacy was higher ( Waltimo et al., 2007) 43

44. Cystic apical periodontitis The recorded incidence of cysts among apical periodontitis lesions varies from 6% to 55% Apical periodontitis cannot be differentially diagnosed into cystic and non-cystic lesions based on radiographs alone Reported incidence of periapical cysts is probably due to the difference in the interpretation of the sections 52% of the lesions were found to be epithelialized but only 15% were actually periapical cysts 44

45. cysts D/D: greater than 1 cm in diameter with well-defined margins Radicular cysts are categorized as: 45

46. Cracked teeth and fractures Careful assessment of the tooth: operating microscope or loupes, an indicator dye- evaluate the degree of severity before embarking on RC retreatment Treatment: Severity of the crack Exposed to the oral cavity: a crack contains bacteria, reinfection of the root-filled canal/ inflammation alongside the fracture line in the PDL 46

47. Endodontic failures can occur by partial or complete fractures of the roots. Prognosis of teeth with vertical root fracture is poorer than horizontal fractures. 47

48. Cracks across the pulpal floor: become infected with bacteria & are therefore more difficult for the clinician to manage Teeth requiring endodontic treatment: may benefit from the placement of a band to prevent fracture Following RCT a full coverage crown or cusp coverage restoration is to protect the tooth from subsequent fracture 48

49. Incomplete debridement of the root canal system Presence of infected and necrotic pulp tissue in root canal acts as the main irritant to the periapical tissue. Thorough debridement of the root canal system is required for removal of these irritants. The poor debridement can lead to residual micro-organisms, their byproducts and tissue debris which further recolonize and contribute to endodontic failure. 49

50. Excessive haemorrhage Extirpation of pulp and instrumentation beyond periapical tissues lead to excessive hemorrhage. Mild inflammation is produced because of local accumulation of the blood. The extravasated blood cells and fluids must be resorbed because otherwise they act as foreign body. Extravasated blood acts as nidus for bacterial growth especially in the presence of infection. 50

51. Chemical irritants Chemical irritants in form of intracanal medicaments, and irrigating solution decrease the prognosis of endodontic therapy if they get extruded in the periapical tissues. 51

52. Iatrogenic Errors Instrument Separation: Cause: Improper / over use of instruments forcing them in curved canals. Separated instruments impair the mechanical instrumentation of infected root canals apical to instrument, which contribute to endodontic failure. Prognosis : Not much affected – Vital pulps Poor – necrosed tooth 52

53. Canal blockage and ledge formation Canal blockage and ledging Incomplete cleaning and shaping of the canals. Because of working short of the canal terminus, bacteria and tissue debris may remain in non-­instrumented area contributing to endodontic failure. 53

54. Perforation: Mechanical communication between root canal system and the periodontium Cause: Lack of knowledge of the anatomy of the tooth, misdirection of the instruments Prognosis : location , time, perforation seal and size of the perforation 54

55. Incompletely filled canals Cause: Incomplete instrumentation or ledge formation, blockage of canal, and improper measurements of working length Several studies have shown that incomplete obturation of more than 2mm short of apex tend to have poor prognosis 55

56. Overfilling of root canals Causes: Failure in determining the apical foramen. Absence of apical stop and constriction in mature teeth Incorrect selection of master cone Open apices Overfilling of the root canals may cause endodontic failure because of continuous irritation of the periapical tissues. 56

57. Anatomic factors Presence of overly curved canals, calcifications, numerous lateral and accessory canals, bifurcations, aberrant canal anatomy like C or S shaped canals may pose problems in adequate cleaning and shaping 57

58. Periodontal considerations An endodontic failure may occur because of communication between the periodontal ligament and the root canal system. Recession of attachment apparatus may expose lateral canals to the oral fluids which can lead to reinfection of the root canal system because of percolation of fluids 58

59. Healing with scar Scar / fibrous healing is not normally failure Common following surgical endodontics: buccal & lingual plates have been perforated by an existing lesion Irregular resolution of the previous radiolucent area. 59

60. SYSTEMIC FACTORS AFFECTING success or failure Nutritional deficiencies Diabetes mellitus Renal failure Blood dyscrasias Hormonal imbalance Autoimmune disorders Opportunistic infections Aging Patients on long term steroid therapy 60

61. 61

62. Factors affecting prognosis of endodontic treatment Presence of any periapical radiolucency  Quality of the obturation Apical extension of the obturation material  Bacterial status of the canal Observation period Post endodontic coronal restoration  Iatrogenic complication 62

63. Before going for endodontic retreatment, following factors should be considered: When should treatment be considered, i.e. if patient is asymptomatic even if treatment is not proper, the retreatment should be postponed. Patient’s needs and expectations. Strategic importance of the tooth. Periodontal evaluation of the tooth. Other interdisciplinary evaluation. Chair time and cost. 63

64. Contraindications of endodontic retreatment Unfavorable root anatomy (shape, taper, remaining dentin thickness) Presence of untreatable root resorptions or perforations Presence of root or bifurcation caries Insufficient crown/root ratio 64

65. Problems commonly encountered during retreatment Unpredictable result Frustration Cost factor Time consuming 65

66. When is endodontics successful? 66

67. Methods to improve success in endodontics Use great care in case selection . Maintain an organized approach . Be certain of instrument position and procedure before progressing. Establish adequate cavity preparation of both the access cavity, which can be improved by modifications of the coronal preparation , and the radicular preparation, which can be improved by more thorough canal debridement—cleaning and shaping. 67

68. Determine the exact length of tooth to the foramen and be certain to operate only to the apical stop, about 0.5 to 1.0 mm from the external orifice of the foramen. Always use pre-curved, sharp instruments in curved canals Use periradicular surgery only in those cases for which surgery is definitely indicated 68

69. Always check the apical density of the completed root canal filling of the patient undergoing periradicular surgical treatment. If found wanting, the apical foramen is prepared and retro filled. Properly restore each treated pulpless tooth to prevent coronal fracture and microleakage . Practice endodontic techniques until the procedures become a routine. 69

70. Treatment options Non surgical endodontic retreatment Surgical endodontic treatment Leave alone Extraction 70

71. When to consider endodontic surgery? Failure of endodontic retreatment Non negotiable/presence of lateral canals Teeth with long, wide posts – Risk of tooth fracture with conventional retreatment Calcified or obstructed root canal in a symptomatic tooth Perforation that can’t be treated non surgically Combined endo-perio lesions 71

72. Factors affecting Outcome of surgical endodontics 72

73. Type of tooth to be treated Location of the tooth Age and sex of the patient Cause of pulpal injury  Number of appointment for root canal treatment Type of root canal obturating material Preoperative and postoperative pain. Occurrence of endodontic failures does not depend on: 73

74. conclusion The outcome data and potential prognostic factors should be considered during treatment options appraisal and planning Despite the fact that most important prognostic factors are beyond the control of clinicians, optimal outcomes for individual cases may still be achieved by performing the procedure to guideline standards If a root canal treatment subsequently fails, non-surgical and surgical retreatments are also more cost-effective than replacement with a prosthesis Ultimately, all sources of evidence must be assessed for biasing influences based on the expertise, treatment predilection, and funding sources 74

75. references Ingle’s Endodontics – 7 th edition Pathways of the pulp – Cohen – 10 th edition Grossman’s endodontic practice – 14 th edition Advanced Endodontics. Clinical Retreatment and Surgery. Rhodes JS Contemporary Endodontic Treatment. Endodontics. Colleagues for Excellence. Fall/ Winter 2003 Nair. P.N.R. On the causes of persistent apical periodontitis: a review. International Endodontic Journal, 39, 249–281, 2006 Orstavik D, Kerekes K, Eriksen HM. The periapical index: A scoring system for radiographic assessment of apical periodontitis. Endod Dent Traumatol 1986; 2: 20-34. 75