endodontic mishaps or procedural errors are those unfortunate occurences that happen

endodontic mishaps or procedural errors are those unfortunate occurences that happen

1. ENDODONTIC MISHAPS PRESENTED BY : DR.RITIKA CHAUDHARY PG 2nd YEAR

2. INTRODUCTION : Endodontic mishaps or procedural accidents are those unfortunate occurrences that happen during treatment, some owing to inattention to detail, others totally unpredictable.

3. PROCEDURAL ERRORS : ACCESS RELATED Treating the wrong tooth Incomplete removal of caries Missed canals Access opening through full coverage restoration Access cavity perforations Canal Shaping and Cleaning Related Canal Blockage and ledge formation Deviation from normal canal anatomy Separation of Instruments Obstruction by previous obturating materials Obturation Related : Under filling of gutta-percha Over filling of gutta-percha Vertical root fracture OTHER PROCEDURAL ERRORS : Instrument aspiration and ingestion Irrigation Related Tissue Emphysema

4. A – TREATING A WRONG TOOTH : REASONS : Misdiagnosis Isolating the wrong tooth RECOGNITION : Realizing the mistake after rubber dam removal Persistence of symptoms

5. PREVENTION : It can be prevented by making a suitable mark on the radiograph and also on the tooth in question in the oral cavity before the application of rubber dam. Alternatively, initial access cavity into the enamel or dentino-enamel junction can be completed before the rubber dam application.

6. B – INCOMPLETE REMOVAL OF CARIES : Secondary caries under the existing restorations is one of the reasons for the need of endodontic therapy. It is recommended that an existing old restoration, especially involving occlusoproximal areas, should be removed in total and access cavity designed accordingly. All caries must be removed from a tooth receiving endodontic treatment.

7. C- MISSED CANALS : CAUSES : Lack of thorough knowledge of root canal anatomy, configuration and its variations. Inadequate access cavity preparation Incomplete deroofing of the pulp chamber MISSED CANALS CAN BE LOCATED BY : Taking radiographs Use of magnifying glasses or endomicroscopes Accurate access cavity preparation Use of dyes such as methylene blue Use of sodium hypochlorite : After thorough cleaning and shaping, pulp chamber is filled with sodium hypochlorite. If bubbles appear in, it indicates either there is residual tissue present in a missed canal or residual chelator in the prepared canal. This is called “ Champagne Test ”.

8. WHITE LINE TEST : In necrotic teeth, dentinal dust moves into orifices, fins and isthmus when performing ultrasonic procedure without water . This dust can form white dot / line that provides a visible road map. RED LINE TEST : In vital teeth , blood emanates from orifices, fin and isthmus area and serves to map and visually aid in identifying anatomy below the pulpal floor.

9. EXPLORER PRESSURE : It can help to identify a missed canal . Firm explorer pressure is used to punch through a thin layer of secondary dentin. PERIO PROBING : circumferentially probing the sulcus around the tooth is an important strategy for locating canal . Gives information as to emergence profile of clinical crown and orientation alignment of underlying root.

10. PIEZOELECTRIC ULTRASONICS : It provides a breakthrough for exploring and identifying missed canals. Ultrasonic systems importantly eliminate the bulky head of the conventional handpiece that frequently obstructs vision .the working ends of specific ultrasonic instruments are 10 times smaller than round burs and their abrasive coatings allow them to precisely prepare away dentin. MICROPENERS : are flexible stainless steel hand instruments . They have limited length cutting blades which ,in conjunction with their 0.04 and 0.06 tapers ,enhance tensile strength ,making it easier to locate , penetrate and perform initial canal enlargement procedures.

11. PREVENTION OF MISSED CANALS : Good radiographs taken at different horizontal angulations. Good illumination and magnification Adequate access cavity preparation Clinician should always look for an additional canal in every tooth being treated.

12. D – ACCESS OPENING THROUGH FULL COVERAGE RESTORATION :

13. E – ACCESS CAVITY PERFORATIONS : Perforation is defined as, the mechanical or pathological communication between the root canal system and the external tooth surface. If the access cavity perforation is : Above PDL attachment : Presence of leakage into the access cavity is often the first indication of accidental perforation. Into PDL : Bleeding into the access cavity is often the first indication of an accidental perforation.

14. CONFIRMATION : Place a small file through the opening and take a radiograph. Commonly used materials for perforation repair include : amalgam, calcium Hydroxide, super EBA, GIC, MTA and Biodentin .

15. PROGNOSIS : Prognosis depends on the following factors : Location of perforation. Length of the time the perforation is open to contamination. The ability to seal the perforation. Accessibility to the main canal.

16. PREVENTION : Thorough examination of diagnostic preoperative radiographs. Checking the long axis of the tooth and aligning the long axis of the access bur with the long access of the tooth. The presence, location and degree of calcification of the pulp chamber noted on the preoperative radiograph. A close attention to the principles of access cavity preparation : adequate size and correct location, both permitting direct access to the root canals.

17. CANAL BLOCKAGE AND LEDGE FORMATION : CANAL BLOCKAGE : Blockage of canal is basically because of apical pushing of dentinal debris which has been removed during shaping and cleaning of the root canal. PREVENTION : Use of small sized instruments first Use the instruments in sequential order Always pre curve stainless steel hand instruments Use reference points and stable silicon stoppers on instruments while cleaning and shaping. Use copious amounts of irrigants. Recapitulate repeatedly Dispose of used instruments, when there are visible signs of wear on the instrument.

18. 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. It is a deviation from the original canal curvature without communication with the periodontal ligament, resulting in a procedural error termed as “Ledge Formation or Ledging”.

19. ETIOLOGY : Not extending the access cavity sufficiently to allow adequate access to the apical part of root canal. Complete loss of control of the instrument if the endodontic treatment is attempted via a proximal surface cavity or through a proximal restoration. Incorrect assessment of the root canal curvature. Erroneous root canal length determination. Forcing and driving the instrument into the canal. Using a noncurved stainless steel instrument that is too large for a curved canal. Failing to use the instruments in sequential order. Rotating the file at the working length (that is, overuse of a reaming action)

20. Inadequate irrigation and/or lubrication during instrumentation. Over-relying on chelating agents. Attempting to retrieve broken instruments. Attempting to prepare calcified root canals. Inadvertently packing debris in the apical portion of the canal during instrumentation (that is, creating an apical blockage).

21. RECOGNITION : Root canal 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 at the apex. When in doubt radiograph of the tooth with the instrument in place is taken to provide additional information.

22. CORRECTION : The use of a small file, No. 10 or 15, with a distinct curve at the tip can be used to explore the canal to the apex. Tear-drop shaped silicone instrument stopper and watch winding motion are valuable. Use a lubricant, irrigate frequently to remove dentin chips, maintain a curve on the file tip, and using short file strokes, press the instrument against the canal wall where the ledge is located.

23. PREVENTION : Accurate interpretation of diagnostic radiographs should be completed before the first instrument is placed in the canal. Finally, precurving instruments and not “forcing” them is a sure preventive measure. Using instruments with noncutting tips and nickel-titanium files. Patency of the canal should be maintained throughout the cleaning and shaping procedure. Work sequentially increasing sizes of instruments without jumping to large numbers.

24. DEVIATION FROM NORMAL CANAL ANATOMY : ZIPPING & ELBOW FORMATION : ZIPPING : It is defined as apical transportation of a curved canal caused due to improper shaping technique. ETIOLOGY : It is commonly seen in curved canals. Failure to precurve the files. Forcing the instrument in curved canal. Use of large stiff instrument to bore out the canal.

25. PREVENTION : Precurve the initial small sized instruments. Use incremental filling technique. Use flexible files Never rotate the instruments in curved canal. When a file is rotated in the curved canal at the apical area, a biomechanical defect results in the form of elbow. In this case, the apical foramen will tend to become a tear drop shape or elliptical and be transported from the curve of the canal. The wide apical portion of the elliptical is known as the zip while the narrow coronal portion is the elbow . Elbow prevents optimal compaction in the apical portion and obturation ends at the elbow.

26. PERFORATIONS Perforation is defined as the mechanical and or pathological communication between the root canal system and the external tooth surface. ETIOLOGY : caries resorptive defects mechanical or iatrogenic events ROOT CANAL PERFORATION : Cervical Midroot Apical Perforations

27. CERVICAL CANAL PERFORATION : CAUSE : process of locating and widening the canal orifice or inappropriate use of Gates Glidden. RECOGNITION : Often begins with sudden appearance of blood. Magnification with either loupes an endoscopes or microscope is very useful. It may be necessary to place a small file and take a radiograph of the tooth.

28. CORRECTION : hemostatics to control bleeding MATERIALS USED : calcium hydroxide , collagen , calcium sulfate , MTA Calcium sulfate barrier along with composite restorations is generally used , where esthetics is a concern. Super EBA have been used when esthetics not an issue. Presently MTA is rapidly becoming the barrier /restorative of choice for repairing non esthetic coronal one –third defects .

29. MIDROOT PERFORATIONS : Occur mostly in curved canals , either as a result of perforating when a ledge has formed during initial instrumentation or along the inside curvature of the root . RECOGNITION : Stripping : is a lateral perforation caused by over instrumentation through a thin wall in the root and is most likely to happen on the inside, or concave ,wall of a curved canal , such as the distal wall of the mesial roots in the mandibular first molars .

30. Stripping is easily detected by the sudden appearance of haemorrhage in a previously dry canal or by a sudden complaint of the patient . CORRECTION : access to midroot perforation is the most often difficult and repair is not predictable . Repair of strip perforations has been attempted both surgically and nonsurgically .

31. APICAL PERFORATION : Cause : straight canal : inaccurate working length and instrumenting beyond apex Curved canal : ledging , apical transportation RECOGNITION : The pt suddenly complains of pain during treatment. The canal becomes flooded with hemorrhage. The tactile resistance of the confines of the canal space is lost.

32. CORRECTION : Re-establish the tooth length short of the original length and then enlarge the canal , with larger instruments, to that length. PROGNOSIS : With successful repair, apical perforations have less adverse effect on prognosis than more coronal perforations .

33. SEPARATION OF INSTRUMENTS : Files and Reamers – most commonly involved CAUSES : Using a stressed instrument Placing exaggerated bends Forcing a file before canal has been opened sufficiently Inadequate access Anatomy of the canal Instrument is advanced into the canal until it binds, and efforts to remove it Manufacturing defects

34. RECOGNITION : Loss of working length Shortened instrument Radiographic confirmation TREATMENT PLAN : Instrument retrieval Bypassing the instrument and making it part of the obturation Surgical intervention

35. RETRIEVAL TECHNIQUES : Checking for the mobility of the instrument, if lying loosely in the coronial third : Using microscopes, K files or H files are placed between the instrument and the dentinal wall, to bypass the obstacle. NaOCI and urea peroxide- Effervescence Or Bubbling Effect makes the instrument to float. Grasping the file – Micro Needle Forceps, Steiglitz or a Hemostat.

36. RETRIEVAL TECHNIQUES : Wedged instruments in Coronal Third MASSERAN KIT : The masseran kit works on the principle of drilling a trepan around the separated instrument to loosen it and then pick up with an endo extractor. STEPS : Enlarge the canal orifice using the round bur. Gain a straight line access to the fractured instrument, using gates glidden drill. Move end cutting trepan bur slowly in anti clockwise direction so as to free 4mm of the fragment. Take extractor and slide it over free end of the fragment. Firmly hold the extractor in place and rotate the screw head until the fragment is gripped. Once gripped tightly, move extractor in anti clockwise direction for removal of all cutting canal instruments and in clockwise direction for removing filling instruments.

37. EXTRACTORS : the concept behind the Masserann technique has been further developed and new extractors have been introduced The Endo –Extractor system has 3 extractors of different sizes and colors (red 80, yellow 50 and white 30). Each extracter has its corresponding trephine bur that prepares a groove around the separated instrument .the Cancellier Extractor kit contains 4 extractors with outside diameter of 0.50, 0.60, 0.70 and 0.80 mm.The Instrument Removal System contains 3 extractors. The black extractor has an outside diameter of 1mm and is used in the coronal one –third of larger root canals .The red and yellow extractors are used in the narrower canals.

38. CANAL FINDER SYSTEM The Original Canal Finder Se system consisted of a handpiece and especially designed files. The system produces a vertical movement with maximum amplitude of 1-2 mm that decreases when the speed increases . It effectively assists in bypassing a fragment ,but caution should be exercised not to perforate the root or apically extrude the fragment. The flutes of the file can mechanically engage with the separated fragment, and with the vertical vibration, the fragment can be loosened or even retrieved.

39. ULTRASONIC INSTRUMENTS : Different sizes and angles of ultrasonic tips are available for this purpose. Eg : ProUltra Endo : 1,2,3 ; ProUltra Endo : 6,7,8 The tip is placed on the staging platform between the exposed end of the file and the canal wall. Precisely removes dentin and progressively exposes the coronal aspect of the fractured file. Vibration applies unscrewing force to the file that will aid in loosening the file. Occasionally they will appear to jump out of the canal.

40. If little care is taken and excessive pressure on the ultrasonic tip is applied, the vibration ,may push the fragment apically or the ultrasonic tip may fracture, leading to a more complicated scenario. Also, to prevent separation of the ultrasonic tip, it is important to avoid unnecessary stress by only activating it when in contact with root tissue(Yoshitsugu Terauchi, personal communication, September 2011) K-type files can be alternatives or ultrasonic tips. the activated file should be of a tip size that enables trephination of dentin around the fragment.

41. However, files that are too small should not be used because they are themselves prone to separation. Also, a spreader can be modified to a less tapered and smaller tip-sized instrument that can be activated to trephine deeply around a fragment. Success rates for fragment removal by using ultrasonics in clinical trials have ranged from 67% by Nagai et al to 88% and 95% recently by Cuje et al and Fu et al, respectively.

42. FILE REMOVAL SYSTEMS : This system has been developed by Terauchi et al, and it is claimed that the amount of dentin removed is minimal. It involves 3 sequential steps that use specially designed instruments. In step 1,2 low-speed burs (28 mm long) are used. The Cutting Bur A, with a diameter of 0.5 mm and a pilot tip, is used to enlarge the root canal, The Cutting Bur B has a cylindrical-shaped tip and a 0.45 mm diameter, so it removes dentin around the coronal part of the fragment. Both burs are flexible, so they can be used in curved canals. They can loosen or even remove the fragment because they are used in a counterclockwise motion. If this fails; step 2 is attempted. In step 2, an ultrasonic tip (30 0.2 mm) is used to prepare a groove around the separated fragment(at least 0.7 mm deep).

43. This usually loosens the fragment or even removes it. Otherwise, step 3 is carried out. In step 3, to mechanically engage the fragment and pull it out of the root canal, a file removal device of 2 sections is used. One part consists of a head connected to a disposable tube (0.45 mm in diameter), with a loop made of NiTi wire (0.08 mm) projecting from it. The second part is a brass body equipped with a sliding handle on the side that holds the wire of the head attachment. When the handle is moved downward, it fastens the loop and vice versa. This system has been effective in laboratory studies and in some clinical cases of instruments separated in the apical part of the root canal when a relatively short retrieval time was reported. However, this system has not been introduced into the market yet.

44. SOFTENED GUTTA PERCHA : It is the simple technique to remove loose fragments located in the apical third of the root canal by using softened gutta-percha (GP) points. SS Hedstrom files #8, #10 and #15 are initially used to partially bypass the fragment and to check that it is loose. Then, the apical 2-3 mm of a size 40, 0.04 taper GP point, or different size and taper according to the canal accommodating the fragment, is dipped in chloroform for approximately 30 seconds. The softened GP is then inserted to the maximum extent into the canal and is allowed to harden for approximately 3 minutes. The GP point and the Hfragment can be then removed by using a delicate clockwise and counterclockwise pulling action. This Conservative technique may assist in removal of loose fragments that are not easily accessible while using other removal techniques.

45. LASER IRRADIATION : The Nd: YAG has been tested recently in laboratory studies for removal of separated instruments. It is claimed that minimum amounts if dentin are removed, reducing the risk of root fracture. In addition, fragments can be removed in a relatively short time (less than 5 minutes) in 2 ways : the laser melts the dentin around the fragment and then H-files are used to bypass and then remove it, and the fragments are melted by the laser. However, there are several concerns with this concept: the probability of root perforation in curved root canals or thin roots, and the temperature rise on the external root surface (up to 27C), with the potential of periodontal tissue damage.

46. Also, heat generated within the root canal can carbonize or even burn dentin, which in turn may disturb the close contact or bond between the filling materials and root canal walls. Although promising results indicate that many of these concerns can be circumvented, vaporizatiob of the separated instrument has yet to be achieved, as was hoped many years ago.

47. BYPASSING THE SEPARATED INSTRUMENT : The ultimate goal of management of separated instruments is not only to retrieve the fragment but also to preserve the integrity of the tooth. With the associated complications, bypassing a fragment located deep in the root canal or beyond the root canal curvature, if possible, may be the appropriate treatment option. Thus, bypassing the separated instrument has been categorized as a successful approach.

48. However, it is possible that a false channel parallel to the original root canal can be created when a clinician attempts to bypass the fragment, which in turn can lead to a roof perforation. Therefore, bypassing is best carried out under high magnification by using hand files and radiographic checks to avoid such complications. Also, ledge formations, secondary separation of instruments, pushing the fragment apically, and complete fragment extrusion are complications that should be anticipated and managed. In addition, it provides enough space to introduce instruments such as ultrasonic tips alongside the fragment.

49. PROGNOSIS : Depends On : Timing of separation Status of pulp tissue Position of separated instrument Ability to retrieve or bypass the instrument

50. PREVENTION : Examine new instruments – defects Careful handling Stressed instrument – DISCARD Adequate knowledge of physical characteristics of the instruments used. Instruments No 6,8 and 10 should be examined carefully to check for signs of stress and should be used only once. Use of canal lubricants Follow sequential instrumentation Major concern with NiTi instruments, tend to fracture without warning.

51. OBSTRUCTION FROM PREVIOUS OBTURATING MATERIALS : When treatment of a previously endodontically treated tooth becomes necessary, the filling material must be removed or bypassed. GUTTA- PERCHA : Gutta-percha and sealer can be removed by the application of : Mechanical force in the form of instrumentation Heat to sear and soften the gutta-percha Solvents Ultrasonics Combinations of the above

52. SILVER CONE : A silver cone is not removed as easily as a gutta-percha cone unless the butt end of the silver cone extends into the pulp chamber. In such cases, the butt end of the silver cone is vibrated with an ultrasonic scaler to break the cementing media. The cone is then grasped with a pair of narrow-beaked (Stieglitz) pliers and is removed.

53. OBTURATION RELATED : OVER/UNDER EXTENDED ROOT CANAL FILLINGS : CAUSE : 1- Under Extension : Failure to fit master cone accurately Poorly prepared canal apically 2- Over Extension : Apical perforation with loss of constriction

54. RECOGNITION : Post-operative radiographs CORRECTION : Under Extension : Retreatment Over Extension : More difficult Successful if the entire gutta-percha is removed in one tug Gutta-percha and many sealers – generally well tolerated and don not automatically require surgical removal If symptoms persist – surgical removal

55. PREVENTION : Confirmation and adherence to the working length. Mastercone radiograph – if any corrections required, can be made.

56. VERTICAL ROOT FRACTURE : It can occur in any phase of therapy, while instrumentation, obturation or post placement. CLINICAL FEATURES : Commonly occurs in facio lingual plane Sudden crunch sound accompanied by pain A suggestive “J” shaped radiolucency or may appear as halo shaped defect around the involved root. Susceptibility of root fracture increases by excessive dentin removal during canal preparation or postspace preparation.

57. TREATMENT : Most cases, extraction is the only option. Root resection or hemisection in multi rooted teeth. PREVENTION : Avoid weakening of the canal wall Minimise internal wedging forces Avoid over preparation of the canal

58. Irrigation RELATED : Unfortunate sequence of events triggered after the solutions are injected into the root canal systems and forced into the periradicular tissues. Caused by any irrigant which has the potential to cause problems if extruded. Sodium Hypochlorite : Immediate inflammatory response followed by tissue destruction. Hydrogen Peroxide : Tissue emphysema

59. RECOGNITION : Pain & Swelling Interstitial Haemorrhage & Ecchymosis Depends on solution concentration & amount. MANAGEMENT : Antibiotics, Analgesics & Antihistamines Ice packs, then warm saline soaks Intramuscular steroids Hospitalization and surgical intervention Constant Monitoring

60. PROGNOSIS : Favourable : If immediate treatment & proper management. Long Term Effects : Paresthesia, Scarring or Muscle weakness PREVENTION : Passive placement of needle No attempt should be made to force the needle apically The needle must not be wedged into the canal The solution should be delivered slowly and without pressure Special Endodontic irrigating needles : Monoject endodontic needle and Pro-rinse

61. TISSUE EMPHYSEMA : Abnormal presence of air in the tissue spaces. CAUSE : Compressed air being forced into the tissue spaces Canal preparation – blast of air to dry the canal Irrigation past the apex with H 2 O 2 Apical surgery – air from a high speed drill.

62. RECOGNITION : Rapid swelling, erythema and crepitus Can be subcutaneous or periradicular air emphysema Dysphagia and dyspnea Migration of air into the neck region could cause respiratory difficulty, and progression into the mediastinum could cause death. MANAGEMENT : Palliative care & observation to immediate medical attention. Broad spectrum antibiotic therapy Administration of 100% oxygen.

63. PREVENTION : Use paper points to dry root canals. Air syringe – horizontal positioning over the access. In surgical procedures – apical access – handpieces – do not direct jets of air into surgery sites.

64. INSTRUMENT ASPIRATION & INGESTION : When used in the absence of a rubber dam, instruments can accidently be aspirated or dropped into the mouth. RECOGNITION : Radiographs of chest and abdomen.

65. MANAGEMENT : In the dental operatory : High- volume suction Hemostats or cotton pliers Once aspirated : Emergency Medical Attention PREVENTION : Proper tooth isolation with rubber dam. Tying a floss to the rubber dam clamp and endodontic files before use.

66. CONCLUSION : Instrumentation during root canal treatment is sometimes associated with unwanted or unforeseen circumstances. A good practitioner should use his or her knowledge, intuition, patience and awareness of his or her own limitations to minimize these procedural patients. A knowledge of the etiologic factors involved in procedural accidents is essential.

67. REFERENCES : Ingle’s 6 th Edition Cohen’s – Pathways Of The Pulp -1 st South Asia Edition Grossman’s Endodontic Practice – 13 th Edition Nisha Garg – Textbook Of Endodontics – 3 rd Edition