ENDODONTIC MISHAPS .AND RE-TREATMENTpptx

Endodontic mishaps presentation shared for education purpose

1. Endodontic mishaps Guided by- Dr. Ramchandra Kabir Dr. Anita kale Dr. Amol Badgire Dr. Pravin Dhore Dr. Abhishek Badade Dr. Madhuri Agrawal Dr. Ajit shinde Dr. Madhura Sarje Presented by- Dr. Priyanka Kombade

2. Contents Introduction Definition Classification According to Ingle and Bakland Walton & Torabinejad Leif Tronstad Guttmann Access related Instrumentation related Obturation related Miscellaneous Conclusion References

3. INTRODUCTION Technological advancements in Dentistry have vastly improved the quality of care provided to the population. But due to their technique sensitivity, some of these procedures carry a higher risk for procedural errors and complications. These procedural errors were termed as “mishap” by Torabinejad (1990). Like other disciplines of dentistry ,an operator may encounter unwanted circumstances during endodontic procedures.

4. DEFINITION Endodontic mishaps or procedural accidents are those unfortunate occurrences that happens during treatment, some owing to inattention to details and others totally unpredictable. Unwanted or unforeseen circumstances during root canal therapy that can affect the prognosis. -Ingle 6 th -Walton & Torabinejad

5. Recognition of a mishaps is the first step in its management. It may be by radiograph or clinical observation or as a result of a patients complain. CORRECTION of mishap may be accomplished in one of the several ways depending on the type and extent of procedural accident. Re-valuation of the prognosis of the tooth involved in an endodontic mishaps is necessary and important. Patient should be informed about procedural accidents.

6. When an accident occurs during root canal treatment The patient should be informed about Torabinejad

7. Proper medicolegal documentation is mandatory. Informed consent.

8. Classification

9. According to Ingle and Bakland

10. Instrumentation related Ledge formation Cervical canal perforations Midroot perforations Apical perforations Separated instruments and foreign objects Canal blockage

11. Over- or under-extended root canal fillings Nerve paresthesia Vertical root fractures Post space perforation Irrigant related Tissue emphysema Instrument aspiration and ingestion Obturation related Miscellaneous

12. According to Walton & Torabinejad (5th Edition) a)Perforations during access preparation b)Accidents during cleaning and shaping Ledge formation Creating an artificial canal Root perforations Separated instruments Other Accidents

13. c) Accidents during obturation Underfilling Overfilling Vertical root fracture d) Accidents during post space preparation

14. 3) According to Leif Tronstad (Clinical Endodontics) Incomplete Analgesia Access cavity Perforations from the pulp chamber Root Perforations Apical perforations Lateral perforation Post-perforations

15. Obliterated root canal Fracture of an instrument Adverse reactions to medicaments Local tissue irritation Neurotoxic reactions Allergic reactions Overfilling of the root canal Vertical root fractures

16. According to James Gutmann, problem solving in Endodontics 5th edition Problem solving in Diagnosis of odontogenic pain Technique in making radiographic images and interpretation Differential diagnosis of bony defects resulting from pulpal and periodontal pathosis In the diagnosis of treatment failure , nonodontogenic pain In tooth isolation, access openings, and identification of orifice locations In working length determination Clinical techniques in enlarging and shaping root canal In cleaning and disinfecting the root canal system Challenges in root canal obturation

17. ACCESS RELATED MISHAPS

18. TREATING THE WRONG TOOTH Treating the tooth without any pulpal disease is considered as a mishap . - Treating the wrong tooth falls under the category of inattention on the part of the dentist. - Misdiagnosis.

19. Recognition Recognized by re evaluating the patient who continues to have symptoms after treatment. Other times the error may be detected after the rubber dam has been removed. Correction Includes appropriate treatment of both teeth one incorrectly opened and the one with the original pulpal problem. It is not prudent to hide such an error from the patient.

20. Prevention Mistakes in diagnosis can be avoided by, obtaining at least three good pieces of evidence supporting the diagnosis. Radiograph showing a tooth with an caries reached pulp / apical lesion. Lack of response to electric pulp testing. Draining sinus tract leading to the tooth apex proved radiographically with a GP point inserted in the tract. Torabinejad 5th

21. Wrong tooth claims resulting from patients perception of error, with related to patients own opinion or the opinion of a subsequent treating dentist, can be defended competently only with complete and accurate dental records . Marking a tooth with a felt tip pen will prevent placing rubber dam incorrectly, avoiding treating the wrong tooth.

22. MISSED CANAL Canals can also be missed because of a lack of knowledge about root canal anatomy or failure to adequately search for additional canals. Missed canals hold tissue and at times bacteria and related irritants that inevitably contribute to clinical symptoms and lesions of endodontic origin.

23. CAUSES Anatomical -some root canals are not readily apparent or easily accessible. Dentist related Lack of knowledge Failure to adequately search for additional canals Failure to remove cervical ledge

24. Anatomic familiarity is essential before preparing the access cavity or retreating a tooth. During treatment, an instrument or filling material may be noticed to be other than exactly centered in the root, indicating that another canal is present. Naocl can be used detect canals –Champagne bubble test Recognition

25. A significant % of failures are related to missed canals. So the clinician must be thorough with normal anatomy and variations in canal anatomy Common variations are.. Maxillary central incisors - one or more extra canal. Maxillary first bicuspids - may be 3 rooted having MB, DB and palatal canals. Maxillary second bicuspids - deep canal divisions or multiple apical portals of exit. Maxillary 1 st molar – MB2,MB3 Mandibular incisors- lingual canal 45% of time. Mandibular premolars - frequently hold complex root canal systems. Mandibular- 1 st and 2 nd - 2 canals in distal root,middle mesial canal C – shaped canal in molars

26. Canal Anatomy:

27. Canal anatomy of mandibular teeth

28. Radiographs analysis is critical when evaluating a failure. Well angulated periapical film taken with cone directed straight on, mesioblique and distoblique reveals 3-D morphology of the tooth. Computerized digital radiography significantly enhances radiographic diagnostics in identifying hidden calcified or untreated canals.

29. The diagnostic reliability of the radiograph after root canal filling H. W. Kersten P. R. Wesselink, S. K. Thoden van velzen International Endodontic Journal In teeth where complete endodontic treatment has been performed,obturation materials are seen radiographically as centered regardless of the selected angle. Conversely ,if obturation materials appear positiones asymetrically within the long axis of the root ,a missed canal should be suspected.

30. Vision is enhanced with Magnification glasses Trans-illuminating devices Dental operating microscopes

31. Missed canals due to inadequate access

32. Piezoelectric ultrasonic in conjunction with the innovative new ultrasonic instruments provide a breakthrough for exploring and identifying missed canals.

33. Tests used in Locating Canals Champagne bubble test - Sodium hypochlorite can aid in the diagnosis of missed or hidden canals by means of the effervescence test. Use of dyes Iodine in potassium iodide, ophthalmic dye (e.g. 1% fluorescein sodium (rose bengal) or 1% methylene blue will act as a 'roadmap' for identifying overlooked canals and fractures. DG 16 Explorer and micro-openers - locating canal and determining angle of root canal orifice

34. Micro openers Dyes like methylene blue ( canal blue – Dentsply)

35. Endodontics: Use of Ophthalmic Dyes in Root Canal Location In order to locate the mesiolingual (MB2) canal, the pulp chamber was flooded with fluorescein sodium. After suctioning the excess, a blue curing light was used to fluoresce the pulp tissue in the chamber including the isthmus between the MB and MB2 canal. The MB2 canal was readily located by the uptake of the dye that emitted bright green fluorescence.

36. Transillumination Red line test Blood, like a dye, maps and aids in the visual identification of the underlying anatomy. A red dot , which is thought to be an offshoot or accessory canal within a canal. White line test Dentinal dust collects into any accessible anatomical area when doing ultrasonic procedures in necrotic teeth without using water. This dust can appear as a white dot or a white line inside a hidden orifice. Magnification is required while performing the red and white line tests, as they can be deceiving at times.

37. Law of centrality : floor of the pulp chamber is always located in the center of the tooth at the level of the CEJ . Law of concentricity : The walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the CEJ . JOE Vol. 30,No.1, Jan 2004 Laws of access opening by Kransner and Rankow

38. Law of the CEJ: Distance from external surface of clinical crown to the wall of pulp chamber is same throughout the tooth circumference at the level of CEJ. The CEJ is the most consistent repeatable land-mark for locating the position of the pulp chamber Law of Color Change: The color of the pulp-chamber floor is always darker than the walls.

39. Law of Symmetry 1: Except for the maxillary molars, the orifices of the canals are equidistant from a line drawn in a mesial-distal direction through the center of the pulp chamber floor Law of Symmetry 2: Except for the maxillary molars, the orifices of the canals lie on a line perpendicular to a line drawn in a mesial-distal direction through the center of the pulp chamber floor

40. Law of Orifice Location 1: The orifices of the root canals are always located at the junction of the walls and the floor. Law of Orifice Location 2: at the vertices of the floor-wall junction. Law of orifice location 3: at the terminus of the root developmental fusion lines.

41. PROBLEM: Unable to observe the pulp chamber floor due to excessive bleeding, inadequate removal of pulp chamber roof, due to restorative materials impinging onto the pulp chamber Cause • This is usually caused by pulp tissue either in the chamber or in the canals Remedy Enlarge the access by removing the pulp chamber roof without touching the chamber floor Place hemostatic agents in the chamber • Use a barbed broach to remove the tissue

42. PROBLEM: Calcification/pulp stones Cause • Degenerating pulp Remedy • Following the complete removal of the pulp chamber roof and cessation of bleeding, a large smooth round bur (#6) can be used to smooth the pulp chamber floor to remove the calcification and delineate the floor-wall junction clearly

43. PROBLEM: Unable to observe the pulp chamber floor due to inadequate light Cause • Access too small • Presence of crowns or restorative materials • Lack of smooth surfaces of walls or pulp chamber floor (usually caused by too small round burs) Remedy • Enlarge access until floor-wall junction can be seen • Remove restorative materials Use accessory light (LED headlight or surgical operating microscope) • Smooth all irregularities on walls and pulp chamber floor with round burs

44. PROBLEM: Floor perforation Cause • Premature attempt to identify orifices • Failing to measure occlusal-furcal distance • Improper identification of the floor-wall junction • Inadequate access Remedy • Remove entire pulp chamber roof before identifying orifice location • Observe floor-wall junction 360 degrees around • Set bur at length less than occluso-furcal distance • Direct accessing bur towards center of the CEJ perimeter

45. PROBLEM: Lateral chamber wall perforation Cause • Failing to mentally image the CEJ • Improper angle of access entry • Using occlusal anatomy to begin access penetration Remedy • Remove entire pulp chamber roof before identifying orifice location • Observe floor-wall junction 360 degrees around • Direct accessing bur towards center of the CEJ perimeter • Choose initial penetrating access point based on CEJ imaged perimeter

46. FAILURE TO EXCAVATE CARIES OR FAULTY RESTORATIONS Removal of all compromised tooth structure before actual pulpal access ensures that sound, restorable tooth structure remains and that an uncontaminated environment is established for aseptic root canal treatment. Failure to remove caries will lead to problems like Salivary and bacterial contamination of the canal system and peri radicular tissues during and between treatments. Inadequate assessment of the restorative needs of the tooth. Loosening and packing of alloy or composite particles in the canals. Fracture of tooth structure between treatment with loss of measurement reference points or loss of tooth.

47. DAMAGE TO EXISTING RESTORATION Endodontic treatment of a tooth with existing porcelain crown is challenging. The crown may sometimes chip, even with the most careful approach: while preparing access cavity. Placing a rubber dam directly on the margin of a porcelain crown. While removing the provisionally cemented new porcelain crown. Correction Minor porcelain chips can at times be repaired by bonding composite resin to the crown.

48. Prevention Removing provisionally cemented crown that can help prevent both crazing of the porcelain. Prevent damage to the margin. Prevent aspiration of the crown by the patient.

49. CROWN FRACTURES Crown fracture of the teeth undergoing root canal therapy The tooth with pre-existent infraction becomes a true pain when the patient chews on the tooth weakened additionally by an access preparation. Recognition Observation – After removal of existing restoration by access preparation. Fracture crown may be mobile.

50. Treatment Extraction of the fracture fragment, if it is of a “chisel type “in which only the cusp or part of the crown is involved. Crown with infraction should be supported with a circumferential bands or temporary crowns during endodontic treatment. Prognosis Prognosis is less favorable and unpredictable. Crown inflation may spread to the root leading to vertical fracture.

51. Prevention: Reduction of the occlusion before working length is established. This also reduces discomfort following endodontic treatment. Bands and temporary crowns.

52. PERFORATIONS Perforations are procedural accidents that can adversely affect the outcome of endodontic therapy. Sinai et al -found the prognosis for a tooth with a perforation depends on The location of the perforation. How long the perforation is exposed to contamination.( duration ) The feasibility of sealing perforation

53. Access cavity perforation The prime objective of an access cavity is to provide an unobstructed or straight line pathway to the apical foramen. Accidents such as excess removal of tooth structure or perforation may occur during attempts to locate canals. Perforation of crown can occur peripherally through sides either of the crown or through the floor of the chamber into the furcation.

54. Furcation perforations are 2 types Direct Stripping Direct perforation occurs during search of canal orifice. It is more of a punched out defect into the furcation with a bur therefore, it is accessible and may be small and have walls. Stripping perforation involves the furcation side of the root surface resulting from excessive flaring with files or drills. The sequalae is inflammation followed by development of pockets.

55. Causes Lack of attention to the degree of axial inclination of a tooth in relation to adjacent teeth or to alveolar bone may result in either gouging or perforation of the crown or the root at various levels. Failure to direct the bur parallel to the long axis of a tooth will cause gouging or perforation. Failure to check the orientation of the access opening during preparation may also result in perforation.

56. Coronal Perforations at or Above the Bone Level Causes… Failure to recognize crown root angulations During removal of caries & restorative materials During the process of locating and widening the canal orifice or inappropriate use of GG drills.

57. Perforations in the Furcation or Below the Bone Level using a surgical-length bur and failing to realize the narrow pulp chamber Misidentification of canals Failure to recognize crown root orientation

58. Recognition Signs of Perforations Sudden pain during the working length determination even after local anesthesia was adequate during access preparation. Sudden appearance of hemorrhage when crown is perforated into the periodontal ligament. Burning pain or a bad taste during irrigation with sodium hypochlorite when access cavity perforation is above the periodontal attachment.

59. Correction or Treatment Perforations above the alveolar crest This is repaired intracoronally without need for surgical intervention. MTA OR BIODENTIN can be used to seal the perforations during endodontic treatment. Perforations into PDL whether laterally or into furcation should be done as soon as possible to minimize the injury to the supporting tissue of tooth. The 2 types of furcation perforation are treated differently and the prognosis varies: Punched out defect should be repaired immediately with MTA or if proper conditions exist (dryness) BIODENTIN Stripping perforation is inaccessible and requires more elaborate approach. It is treated either surgically or non-surgically.

60. Considerations influencing perforation repair Variables must be considered individually and collectively to properly guide treatment Level Location Size Time Others. Periodontal conditions Esthetics Vision Materials used- Haemostatics Barrier materials – Resorbable barriers & Non resorbable barriers Restoratives

61. Haemostatics A dry field is necessary to enhance vision & to improve skills of the clinician Ca(OH)2 – commonly used, passively syringed into the canal .. kept for 4- 5 mts.. flushed with NaOcl. prolonged bleeding – given as interappoinment dressing Others.. Collagen Freeze dried bone MTA Ferric sulphate is the best haemostatic, but leaves coagulum which promotes bacterial growth

62. Barrier Materials Barriers help to produce a "dry- field'' and also provide an internal matrix or "back stop" to condense restorative materials against. In general, barriers can be divided into resorbable & non resorbable, Barrier should conform to anatomy of the furcation or root surface involved

63. The materials commonly used include, Amalgam, super EBA resin cement, Composite bonded restoratives, Calcium phosphate cement and MTA Other biomimetic materials

64. Labial perforation. (A) Preoperative radiograph; (B) labial perforation; (C) glass ionomer repair following placement of a barrier; (D) postoperative radiograph.

65. Surgical Treatment:- Surgery requires more complex restorative procedures and more demanding oral hygiene from the patient. Surgical alternatives are Hemisection, Bicuspidization, Root amputation Intentional replantation. Teeth with divergent roots and bone levels that allow preparation of adequate crown margins are suitable for either hemisection or bicuspidization.

66. Prevention Thorough examination of diagnostic preoperative radiograph is paramount step . Aligning the long axis of access bur with the long axis of tooth. The presence ,location and degree of calcification of the pulp chamber should be noted on preoperative radiograph. Knowledge of tooth anatomy is essential for performing root canal therapy.

67. INSTRUMENTATION RELATED

68. Loss of working length During cleaning and shaping = common procedural error. NOTED = during master apical file OR during selection of master cone radiograph Causes = Rapid increase in file size Accumulation of dentinal debris Variations in reference point Lack of attention in malpositioned teeth

69. Prevention Use of sound and reproducible reference points Precurve all instruments for use in curved canals Always maintain the original angulation of radiograph Copious irrigation and recapitulation Use of sequential file size

70. LEDGE FORMATION “A ledge is an artificially created irregularity on the surface of the root canal wall that prevents the placement of instruments to the apex of an otherwise patent canal”

71. Etiology (1) Not extending the access cavity sufficiently prevents adequate access to the apical part of the root canal (2) Complete loss of control of the instrument if the endodontic treatment is attempted via a proximal surface cavity or through a proximal restoration (3) Incorrect assessment of the root canal direction (4) Erroneous root canal length determination (5) Forcing and driving the instrument into the canal (6) Using a noncurved stainless steel instrument that is too large for a curved canal (7) Failing to use the instruments in sequential order Jafarzadeh and Abbott , JOE 2015

72. (8) Rotating the file at the working length (that is, overuse of a reaming action) (9) Inadequate irrigation and/or lubrication during instrumentation (10) Over-relying on chelating agents (11) Attempting to retrieve broken instruments (12) Removing root filling materials during endodontic retreatment (13) rapid attempt to prepare calcified root canals (14) Inadvertently packing debris in the apical portion of the canal during instrumentation (that is, creating an apical blockage) Jafarzadeh and Abbott , JOE 2015

73. Recognition: Ledge formation is suspected when instrument can no longer be inserted into the canal to full working length. Loss of normal tactile sensation of the tip of the instrument binding in the canal. A radiograph shows change in estimated working length

74. Correction of ledge Small file, No. 8 or 10, with a distinct curve at the tip The curved tip should be pointed toward the wall opposite the ledge (“tear-shaped” stop) “Watch-winding” motion often helps advance the instrument Whenever resistance is met the file is slightly retracted ,rotated and advanced again until it bypasses the ledge. A radiograph should confirm working length

75. The following tips are followed while completing the canal preparation. Use of lubricant Frequent irrigation Short file strokes Press the instrument against the canal wall

76. Prevention To overcome the problem of stripping caused by students. University of South California developed a technique termed as anticurvature filing, stressing the importance of maintaining mesial pressure on the enlarging instruments to avoid the delicate danger zone of the distal wall. Accurate interpretation of diagnostic radiographs should be completed before the first instrument is placed in the canal. The radiograph should be examined for curvatures, length and initial size.

77. Curvatures: Severe coronal curvature predisposes the apical canal to ledging. Length: Longer canals are more prone to ledging than shorter canals Initial size: Canals of smaller diameter are more easily ledged than larger-diameter canal.

78. Prognosis : Failure of root canal treatment associated with ledging depends on - The amount of debris left in the uninstrumented unfilled portion of the canal.

79. ROOT PERFORATIONS: Roots may be perforated at different levels during cleaning and shaping. Radicular perforations can be identified CERVICAL. APICAL PERFORATIONS MIDDLE.

80. Perforations in all locations are caused by 2 main errors:- Creating a ledge in the canal wall during initial instrumentation and perforating through the side of the root at the point of canal obstruction or root curvature. Using too large or too long an instrument and either perforating directly through the apical foramen or wearing a hole in the lateral surface of the root by over instrumentation (canal stripping).

81. Treatment Sequence When there is a perforation The canal is open but has not been optimally shaped Perforation defect should be repaired before proceeding with definite endodontic treatment. However any given perforated canal should be optimally enlarged and prepared to improve access to the defect, to increase visualization, and to minimize post-repair instrumentation.

82. Restoratives Restoratives should be Nonresorbable Biocompatible Esthetically pleasing Provide complete seal The choice of the restorative repair material is based on the technical access to the defect, the ability to control moisture & the esthetic consideration.

83. Prevention Thorough examination of diagnostic pre-operative radiographs . A thorough knowledge of tooth anatomy, specifically pulp anatomy is essential for prevention of perforation.

84. Perforations can be avoided by preparing adequate access.

85. Cervical Canal Perforations: The cervical portion of the canal is most often perforated during the process of locating and widening the canal orifice or inappropriate use of Gates-Glidden burs.

86. Recognition Recognized by the sudden appearance of blood, which comes from the PL space. Rinsing and blotting may allow direct visualization of the perforation. If the perforation is not visible directly a small file can be kept in the area that has been exposed and radiograph taken.

87. Magnification with loups, endoscope or a microscope. The electronic apex locators can also be used to locate the perforations.

88. Prognosis:- Prognosis is considered to be reduced in this type of perforations and surgical correction is necessary if a lesion or symptoms develop. Prevention Reviewing each tooth’s morphology prior to entering its pulp space. Radiographically verifying one’s position in the tooth can turn one back on tract before it is too late.

89. Mid Root Perforations: Lateral perforations at mid root level tend to occur mostly in curved canal either as a result of perforating when a ledge has formed during initial instrumentation or stripping. Strip perforations The cervical portion of the instrument straightens the canal in multirooted teeth, leading eventually to communication with the furcation. In the danger zone there is less tooth structure compared with the more peripheral portion (safety zone) or the root dentin.

90. Recognition Sudden appearance of hemorrhage in a previously dry canal. Sudden complaint by the patient. Paper points placed in canal can confirm presence of location of perforation. Apex locators. Optical microscopes can be used for visualization.

91. Correction These defects are ovoid in shape and typically represent relatively large surface area to seal. Middle one-third perforations have the same technical consideration as coronal one-third perforations except the defect is located deeper and further away from the access cavity.

92. Apical Perforations Perforation in the apical segment may be the result of file not negotiating a curved canal or not establishing accurate working length and instrumenting beyond the apical confines. A new portal of exit can be created if incorrect instrumentation is used when the apical third of the canal is curved. Blockage of the canal with dentin mud or forceful attempts to bypass a ledge can lead to this mishap Perforation of a curved root may be the result of “ledging” “apical transportation” or apical zipping.

93. Recognition Sudden complain of pain during treatment Canal becomes flooded with blood Loss of tactile resistance of the confines of the canal space. Apex locators can be used. A paper point inserted to the apex will confirm a suspected perforation. Extension of the largest file beyond the radiographic apex is also a sign.

94. Corrections Various treatment options are considered based on the location and width of the perforation. Iatral opening is considered like a new foramen, one is now dealing with 2 foramina, one natural and other iatral. Obturation of both of these foramina and of the main body of the canal requires the vertical compacting techniques with heat-softened GP. Often surgery is necessary if a lesion is present apically.

95. The canal is negotiated for the physiologic terminus. The file is gently worked to negotiate the physiologic pathway, establish patency and pave the way for the successively large instrument. The next sequentially large, precurved file is then inserted and carried apical to the perforation but not necessarily to length. Apical perforation can also occur in a perfectly straight canal if instrument used exceeds the correct working length. This destroys the resistance form of the root canal preparation at the CDJ making it difficult to control the apical extensions of the root canal filling.

96. The treatment includes re-establishing tooth length short of the original length and then enlarging the canal with larger instruments, to that length. Careful adaptation of the primary filling point, often blunted is imperative. Creating an apical barrier is another technique that can be used to prevent overextension during root canal filling. Materials used for developing such barriers include dentin chips, calcium hydroxide powder, proplast, hydroxyapatite and MTA.

97. Prevention Weine et al have recommended the use of a flared preparation to reduce the incidence of elbow formation in the apical portion of the canal. Apical transportation has been shown to be a common undesirable result from the instrumentation of curved canals.

98. Cimis et al reported that 46% of curved canal exhibited various degree of apical transportation after instrumentation. Briseuo and Sounabend evaluated the ability of endodontic instruments to remain in the central axis of the canal. The most difficult area to clean and to maintain canal shape was the apical area. They reported that all instruments tend to straighten curved canals resulting in elbow formation and transportation of the apex.

99. A number of instrumentation techniques and devices have been advocated for use in small, curved canal to decrease apical transportation. These include step back, crown down, balanced forces and sonic and ultrasonic techniques.

100. Separated instruments and foreign objects

101. During root canal preparation procedures, the potential for instrument breakage is always present. It may be a separated file, a sectioned silver point, a segment of Lentulo, a gates glidden drill, a portion of a carrier-based obturator or any other device obstructing the canal.

102. The potential to safely remove a broken instrument is guided by anatomy, including the diameter. length and curvature of the canal, and limited by root morphology, including the circumferential dimensions and thickness of dentin . depth of an external concavity.

103. In general If one-third of the overall length of an obstruction can be exposed, it can usually be removed. Instruments that lie in the straightway portions of the canal can typically be removed. Separated instruments that lie partially around canal curvatures, although more difficult can often times be removed if straight-line access can be established to their most coronal extents.

104. If the broken instrument segment is apical to the curvature of the canal and safe access cannot be accomplished then removal is usually not possible and in the presence of signs or symptoms, surgery or an extraction will be at times be required. The type of material comprising an obstruction is another important factor to be considered. E.g. stainless steel files tend to be easier to remove as they do not further fracture during the removal process.

105. Recognition Occurs when the confirmed working length is no longer attained. Radiographic evaluation

106. Coronal and Radicular Access: Before commencing with efforts to remove a broken instrument the clinician should thoughtfully observe different horizontally angulated pre-operative radiographs. Coronal access is the first step in the removal of broken instruments. High speed, friction grip, surgical length burs are selected to create straight line access to all canal orifices. Radicular access is the second step in removal of a broken instrument.

107. Silver points Three fine Hedstroem files are worked down alongside silver point. “split-tongue” excavator Loop of orthodontic wire

108. Steiglitz forceps before and after modification on a prosthetics lathe.

109. silver point flush with canal orifice being removed with ultrasonic aid. Use of Ultrasonics..

110. Instrument Retrieval systems Masserann kit ( MICROMEGA) Trephine- removes dentine Remover – rod in tube

111. ENDO EXTRACTOR

112. Ultrasonic Techniques

113. Removal by chemical method Agents like. Iodine trichloride, HNo 3, HCl, H 2 SO 4 , FeCl 3. → Intentional corrosion Diadvantage: Most of the instruments are stainless steel → No corrosion More harmful if the solution goes beyond apex.

114. Comparison of the Different Techniques to Remove Fractured Endodontic Instruments from Root Canal Systems Eur J Dent. 2009   Instrument removal attempts were undertaken on 63 straight and 30 curved canals containing a pre-fractured instrument using the ultrasonics under the visualization of an operating microscope or conventional methods. In straight canals, a Masseran Kit was additionally used

115. The overall success rate was found 93.3% with ultrasonics and 66.6% when only conventional methods were used in curved canals. In straight canals, also the success rate was the highest with ultrasonics (95.2%). This was followed by conventional method (80.9%) and the least by Masserann Kit (47.6%). When the success rate was investigated according to the location of the broken instruments, the lowest rate was found in the apical third of root canal.

116. Prevention Prevention of separation mishaps can be partially accomplished by. Careful handling of instrument Stressed instrument may be recognized by the flutes which may appear “unwound”, when the spacing appears uneven between the cutting edges of a reamer or file, the instrument is stressed and should not be used. Instrument No.8 and 10 should be used only once.

117. This smaller instrument should not be forced or wedged into a canal; rather, they should be teased gently into place. An instrument that cannot be inserted to the desired depth should be removed and the tip modified slightly by bending before resuming the pathfinding process.

118. Use of canal lubricant. Sequential instrumentation, using the “quarter-turn” technique, and increasing file size only after the current working file fits loosely into the canal without binding. The gradual increase in file sizes, even to include the currently available half-sizes, and avoiding the risk to finish will go a long way toward preventing mishaps.

119. Various etiological factors seem to be associated with calcifications are caries, traumas and aging. Success in negotiating small or calcified canals is predicted on a proper access opening and identification of the canal orifice. The distance from the occlusal surface to the pulp chamber is measured from the preoperative radiograph. Calcified canals

120. Management of calcified Canals At this suspected point a fine instrument number 8 or 10 K- file, is placed into the orifice, and an effort is made to negotiate the canal. An alternative choice is to use instruments with reduced flutes, such as a canal pathfinder which can penetrate even highly calcified canals. EDTA, a chelating agent, is used as it removes the calcified deposition by demineralizing and softening the root canal dentine. C pilot files D finder

121. OBTURATION RELATED

122. Objectives Total debridement of the pulpal space. Development of fluid tight seal at the apical foramen. Total obliteration of root canal.

123. Mishap Encountered in Preparation to Obturate the Canal A) Failure to sit the master GP cone to full working length This is common problem in root canal obturation during lateral condensation.

124. 1) Breakage of the master cone during trial placement Hold the cone with a cotton forceps. Immerse the cone vertically in hot tap water (130 ° ) until the compressive force of the pliers indents the cone (1 to 2 sec). Remove the cone and immediately immerse it vertically in cold tap water (60 ° ) or in alcohol (70% isopropyl) for 5 to 10 seconds. Disinfect the cone as usual and insert it into the prepared canal.

125. B)Failures encountered during active obturation procedures i) Failure to place the condensing instrument to the prepared apical seat. Lack of proper canal shape and taper Use of condensing instruments that are too large . Use of a straight condensing instrument in a curved canal .

126. A) Overfilling of Canals or Overextension of the Obturating Material: Overfilling implies that root canal systems have been filled in three dimensions and a surplus of filling material extrudes beyond the confines of the canal. Overextended root filling is limited solely to the vertical dimension of the root canal filling material relative to the apical foramen. MISHAP IDENTIFIED DURING POSTOBTURATION EVALUATION

127. The major causes of placing the root canal filling material beyond the apical constriction in either overfilling or overextension Excessive instrumentation beyond the apical constriction, resulting in the lack of an apical dentin matrix. Unanticipated communicating resorptive defects anywhere in the canal system. Defects incorporated into the canal system during cleaning and shaping, such as zips, perforations, strips. Excessive condensation force. Excessive amounts of sealer. Use of too small a master cone.

128. Secondary causes of this problem include the following: Failure to coat the accessory cones with a thin layer of root canal sealer (lateral condensation) Failure to insert accessory cones to the full length of spreader penetration Use of accessory cones with very fine tips that curl up or kink on placement Use of too large a spreader (lateral condensation) or plugger (vertical condensation, thermoplasticized gutta-percha injection techniques) Use of a rapidly setting root canal sealer or an improperly mixed sealer that may set up too fast.

129. Guttapercha Removal GP is best removed → in a progressive manner → to prevent displacement of irritants periapically. There are various techniques available and on many occasions, a combination of various techniques should be used Heat removal Heat and instrument removal File & chemical removal Paper point & chemical removal Ultrasonic removal Rotary removal

130. Heat and Instrument Removal This method employs heat and H-files A heat instrument (plugger) is plunged into the GP and immediately withdrawn to heat-soften the material. A size 35, 40 or 45 H file is then selected and quickly, but gently, inserted into the thermo softened mass. When the GP cools, it will freeze on the flutes of the file. In poorly obturated canals, removing the file can, at times, eliminate the engaged GP in one motion.

131. Heat removal A power source with a specific heat carrier instruments such as 5004 Touch-N-Heat or System B has been used to thermo soften and remove "bites" of GP from Root canal systems. Limitation is cross sectional diameter of under prepared systems & Around pathways of curvature Technique is Activate the instrument till it is red hot ↓ plunge into coronal most aspect of Gp ↓ Deactivate as it cools ↓ Removal of an attached “ bite ” of Gp

132. File and Chemical Removal Used to remove GP best from small and curved canals. Chloroform was the reagent of choice. Others : xylene, eucalyptol, Halothane This sequential technique involves filling up pulp chamber with agent Selecting appropriate size K-file Gently “picking” in to GP Frequent irrigation with the agent creates a pilot hole Progressively continued till apical third

133. Ultrasonic Removal Presents a useful technology to rapidly eliminate GP. The energized instruments produce heat ↓ thermally softens the GP ↓ Specially designed ultrasonic instruments are carved into canals ↓ GP will float coronally into pulp chamber

134. Prevention Confirmation and adherence to canal working length throughout the instrumentation procedure. Taking a radiograph during initial phase of obturation.

135. VERTICAL ROOT FRACTURE

136. VERTICAL ROOT FRACTURES Vertical root fractures, or VRFs, usually are characterized by an incomplete or complete fracture line that extends through the long axis of the root toward the apex. JADA VOL 134 2003

137. The cause of VRFs mainly is iatrogenic, resulting from dental treatment for example Excessive canal shaping Excessive pressure during compaction of gutta-percha Excessive width and length of a post space in relation to the tooth’s anatomy and morphology. Excessive pressure during placement of the dowel Trauma is the most likely cause of VRFs in vital teeth, typically occurring from physical trauma, clenching or bruxism, or occurring in teeth undergoing apexification. JADA 134:2003

138. Teeth with VRFs have Pain, swelling Presence of a sinus tract A deep, narrow, isolated periodontal pocket along one surface of the tooth. The most common radiographic findings Thickening of the PDL Vertical bone loss; Localized periradicular bone loss ( “halo”effect). If the demineralized area of bone loss (the halo) completely surrounds the root, this typically indicates that the root fragments are completely separated and a VRF has developed.

139. swelling Thickening of pdl space Halo effect Sinus track formation

140. Vertical root fracture can occur during different phase of treatment: Instrumentation Obturation Post placement

141. During obturation Lateral and vertical condensation technique Risk is high ,if to much pressure is exerted during compaction

142. During post placement If the force is applied apically during seating or cementation.

143. Tests

144. Overprepared root canal preparation

145. Correction Extaction of the involved teeth.(single root) Root resection (multirooted )

146. Prevention Endodontically treated teeth are more brittle. Overpreparing should be avoided because Overflaring results in unnecessary removal of dentine along the canal walls. Use of passive, less forceful obturation technique and seating of post.

147. SEDDONS CLASSIFICATION (endodontic topic 2005,12,52-70) Seddon’s classification is derived from the extent of nerve injury. NEUROTEMESIS. AXONTEMESIS. NERVE PARASETHESIA

148. NEUROTEMESIS Is the most severe nerve injury because conduction is completely disrupted resulting in the loss of anatomic integrity of endoneurium,perieurium and epineurium. Neurotemesis leads to anesthesia with a loss of feeling or sensation. Recovery is unlikely or limited.

149. Axomotemesis Is a less severe injury results in damage to the axons . It causes parasthesia ,an abnormal altered sensation,which shows some degree of sensory recovery after several month.

150. Causes Endodontic therapy do cause paraesthesia Overfilling/overextension. over instrumentation. Injury to inferior alveolar nerve.

151. Signs and symptoms Unilateral loss of sensitivity of lips and gums. Numbness Tingling sensation and dryness of the affected mucosa,often preceded by intense pain in affected area.

152. Massive overextension of sealer which causes nerve paresthesia

153. Inferior Alveolar Nerve Injury Caused by Thermoplastic Gutta-Percha Overextension ( J Can Dent Assoc 2004; 70(6):384–7) Surgical debridement of inferior alveolar nerve and decompression of nerve was done for the patient

154. Correction Correction of these iatral neuropathies is often through nonintervention and observation. Gatot (oral surgery 1986 ;62:704) Systemic prednisone (to shorten the course of condition) prevent secondary fibrosis and lessen the severity of sequelae.

155. Correction of inferior alveolar nerve injury Alveolar nerve injury are neuropraxias and thus resolve spontaneously within 6 months of time. “Wait and observe” approach should be followed.

156. POST SPACE PERFORATION A well-done root canal procedure can be destroyed in few seconds by a misdirected post space preparation. End cutting drills such as those used for the para-post system need careful attention to avoid lateral perforation; round burs can also be dangerous if care is not exercised in watching the direction of bur. MISCELLANEOUS

157. Recognition Sudden presence of blood in the canal. The presence of a sinus tract stoma or probing defects extending to the base of the post . Radiographic evidence (lateral radiolucency along the root.)

158. Correction Post removal Sealing the perforation Extaction of the tooth

159. Post-removal Factors influencing the successful post-removal Operator judgment, training, experience of operator Utilizing the best technologies and techniques Knowledge of anatomy of teeth (length, circumferential dimension, curvature of root, concavity of root if present). This information is best obtained by three well angulated radiographs. Post-type or cementing agent Availability of interocclusal space Existing restoration.

160. It is common to encounter endodontically treated teeth that contain posts These have to be removed.. When previous treatment is failing To improve design, mechanics and esthetics of a new restoration

161. Posts can be Parallel verses tapered Actively engaged versus non actively retained Metallic versus new nonmetallic compositions. Posts retained with classic cements (e.g. ZnPO4) can be generally removed when compared to GIC and Resin based cements. Indications for post removal Insufficient length of post diameter of post relative to root canal diameter Retention of post Root canal filling apically

162. Removal of fibre posts Fibre posts are constructed of carbon fibre, glass or quartz fibers in a composite matrix They are normally bonded into the root canal using dentine bonding agents. . difficult to remove. Fortunately, most of the posts that will need to be removed during root canal retreatment will have failed as a result of coronal microleakage and, therefore, the bond interface has often failed.

163. Removal of fiber post Round swan neck bur (DT205 LN bur ,dentsply maillefer) can be used to create a pilot channel down the centre of the post. Peeso drills and gates glidden .

164. Prognosis Prognosis of the teeth with with root perforation during post preparation depends on root size, location relative to epithelial attachment and accessibility for repair. Teeth with small root perforation that are located in apical region and are accessible for surgical repair have better prognosis. If the perforation is close to gingival sulcus ,the risk of periodontal pocket formation is high….prognosis is bad.

165. Prevention Good knowledge of root canal anatomy. Planning the post space preparation based on radiographic information regarding the location of the root and its direction in alveolar bone.

166. One of the principal goal of root canal treatment is cleaning of root canal system prior to placement root canal filling .This is usually achieved by combination of mechanical instrumentation followed by medication appointments. Irrigation of root canal system in between instrumentation is mandatory to completely debris and clean the root canal . IRRIGANT RELATED MISHAPS

167. An unfortunate sequence of events is triggered after the solution is injected into the root canal system and forced into the periradicular tissue. The consequences of extruding concentrated NaOCl into the periradicular tissue during root canal irrigation are, a rapidly developing swelling and haematoma immediately. Later an extensive bruise and local necrosis of the oral mucosa will be seen.

168. Cause of hypochlorite accident Forcefully injecting the irrigant. Irrigating needle wedged into the root canal. Irrigating a tooth with a large foramen,apical resoption,immature apex.

169. Recognition Irrigant-related mishap will be readily apparent. The patient may immediately complain of severe pain, and swelling can be violent and alarming. The effects on the patient will of course depend on the type of solution used, the concentration and amount of exposure. The initial response stage may be characterized by swelling, pain, interstial hemorrhage and ecchymosis.

170. Treatment: Irrigation of the root canal immediately with saline to dilute the toxic irrigant. Antibiotics to prevent potential spread of infection related to tissue destruction. Analgesics for pain. Antihistamines can also be helpful in some cases. Ice packs initially, followed by warm saline soaks the following day to reduce the swellings.

171. The use of IM steroids, and, in more severe cases, hospitalization and surgical intervention with wound debridement, may be necessary. If NaOCl is injected inadvertently to maxillary sinus, immediate lavage of the sinus through the same root canal pathway of at least 30 ml of sterile water or saline should prevent damage of the sinus lining.

172. Treatment Hamalmelis virgianiana extract resolved the burn in 2 weeks. This plant extract has demonstrated anti inflammatory properties that promote healing of cutaneous injury by modulating cytokine function and keratinocyte or endothelial cell proliferation. H.virgianiana has a good scavenging property against free radicals ,such as those produced by NaOl.

173. Treatment Intra venous dexamethasone(8mg 3 times for 2 days) Intra venous amoxicillin (1.0mg 3 times a day) Diclofenac (50mg 3 times a day)

174. Prognosis Is favorable, but immediate treatment, proper management, and close observation are important. The long-term effects of irrigant injection into the tissue have included paresthesia, scarring and muscle weakness.

175. Prevention No attempt should be made to force the needle apically. The needle must not be wedged into the canal, and the solution should be delivered slowly and without pressure. Special endodontic irrigating needles such as the monoject endodontic needle with a modified tip and side orifice or the blunt-end will prevent this mishap.

176. The irrigating needle should be bent at the center to confine the tip of the needle to higher level in root canal. The needle never be placed so deeply into the canal that it binds the walls. Irrigation should be stopped if the needle jams or if there is any detectable resistance on pressing against the pluger of the syringe. The hub of the irrigating needle should be checked for tight fit to prevent inadvertent separation.

177. Instrument Aspiration and Ingestion Aspiration or ingestion of a foreign object is a complication that can occur during and dental procedure. Endodontic instruments, used in the absence of a rubber dam, can easily be aspirated or swallowed if inadvertently dropped in the mouth.

178. Thomsen et al. reported an unfortunate result of doing endodontic therapy without the use of rubber dam. The patient developed appendicitis from the ingested file and required surgery

179. Immediately after the mishap Fragment in duodenum

180. Recognition If an instrument aspiration or ingestion is apparent the patient must be taken immediately to a medical emergency facility for examination, which should include radiographs of chest and abdomen.

181. Correction In the dental operatory is limited to removal of objects that are readily accessible in the throat. High volume suction, particularly if fitted with a pharyngeal tip, can be useful in retrieving lost items. Hemostats and cotton pliers can also be used. Once aspiration has taken place, timely transport to a medical emergency facility is essential.

182. Prevention Can best be accomplished by strict adherence to the use of a rubber dam during all phases of endodontic therapy. If a rubber dam clamp is placed on the tooth to be treated before rubber dam placement, aspiration of a loosened clamp can be avoided by attaching floss to the clamp before placement.

183. Flare-up is described as the occurrence of pain, swelling or the combination of these during the course of root canal therapy, which results in unscheduled visits by patient. Definition- “An acute exacerbation of periradicular pathosis after initiation or in continuation of root canal treatment.” - American Association of Endodontics (AAE) Flare-ups may occur with the best of the therapy, but most flare-ups occur when improper treatment is rendered or when insufficient time is allowed for specific modalities in therapy Endodontic flare-up

184. ETIOLOGY polyetiologic phenomenon. Comprise mechanical, chemical and/or microbial injury to the pulp or periapical tissues resulting in the release of myriad of inflammatory mediators. Pain then occurs due to the direct stimulation of the nerve fibers by these mediators or edema resulting in an increase in the hydrostatic pressure with consequent compression of nerve endings

185. Management of flare-ups • Proper diagnosis. • Long acting local anesthesia. • Determination of proper working length. • Complete debridement. • Occlusal reduction. • Placement of intracanal medicament in case of multi-visit root canal treatment. • Medications. • Closed dressing. • Behavioral management.

186. CONCLUSION Our ethical obligation to protect patients from harm is met when we as a professional can provide advanced therapies in a controlled manner with patient welfare as an over-riding priority. A successful operator learns from the past experiences and applies them to future challenges. Mistakes are painful when they happen, but years later a collection of mistakes is what is called experience, which leads to SUCCESS. - Denis Waitley

187. References Pathways of pulp – Cohen 9 th Endodontics - Ingle 5 th edtn and 6th Endodontic therapy - Weine Endodontic Practice - Grossman 12 th Problems Solving in Endodontics – Guttman 4 th edtn. DCNA - 2004 www.google.com