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DEPARTMENT OF
CONSERVATIVE DENTISTRY AND ENDODONTICS
SEMINAR TOPIC
ERRORS IN ENDODONTIC PROCEDURES
AND
THEIR MANAGEMENT
GUIDED BY: PRESENTED BY –
DR DAKSHITA JOY SINHA DR DEEPIKA MEHRA
(PROFESSOR AND HEAD) MDS - IIND YEAR ( 2020-2023)
CONTENTS
- Definition
- Classification
- Access Related Mishaps Ø Treating Wrong Tooth Ø Missed Canal Ø Damage To Existing Restoration Ø Access Cavity Perforation Ø Crown Fracture
- Instrumentation Related Ledge Formation Cervical Canal Perforation Mid Root Perforation Apical Perforation Separated Instrument And Foreign Object Canal Blockage
- Obturation Related Over Or Under Obturation Nerve Paresthesia Vertical Root Factures
- Miscellaneous Post space perforation Irrigants related mishaps Tissue emphysema Instrument aspiration and ingestion
- Conclusion
- References
- Wrong treatment: the patient complained that the operator has treated either a wrong tooth or treated a tooth due to an incorrect reason.
- Prolonged treatment: prolonged management of patient, including extra appointments and associated complications.
- Lack of information: insufficient information was provided to the patient regarding vital diagnostic or treatment procedures.
- Others: such as claims that are not associated with endodontic procedures, including an “unnecessary” endodontic procedure based on false diagnostic or a non-endodontic problem.
- Classification According to Walton & Torabinejad
- Procedural accidents during access preparation
- Accidents during cleaning & shaping Ø Ledge formation Ø Creating an artificial canal Ø Root perforations Ø Separated instruments Ø Other accidents
- Accidents during obturation Underfilling Overfilling
- Vertical root fractures
- Accidents during post space preparation
- ACCORDING TO INGLE Access related 1.Treating the wrong tooth
- Missed canals
- Damage to existing restoration
- Access cavity perforations
- Crown fractures Instrumentation related
- Ledge formation
- Cervical canal perforations
- Midroot perforations
- Apical perforations
- Separated instruments and foreign objects
- Canal blockage
- Management of a Mishap I. Recognition of a mishap II. Correction of a mishap III. Re-evaluation of the prognosis of the tooth involved IV. How to prevent a mishap
- Access Related Mishaps
- Treating The Wrong Tooth Cause
- Inattention on the part of the dentist
- Misdiagnosis
- Recognition
- Patient continues to have symptoms after treatment
- Error may be detected after the rubber dam has been removed.
- Correction
- Appropriate treatment of both teeth:
- The one incorrectly opened
- The one with the original pulpal problem
- Prevention
- Mistakes in diagnosis can be avoided by obtaining at-least 3 good pieces of evidence supporting the diagnosis.
- Obtaining as much information as possible before making the diagnosis.
- Marking the tooth to be treated before isolating it with rubber dam. Missed Canals
Damage To Existing Restorations
- Endo-treatment of a tooth with existing porcelain crown is challenging.
- Crown may chip off even with the most careful approach while preparing access cavity placing rubber dam clamp on the margins Correction
- Minor porcelain chips can be at times repaired by bonding composite resin to crown
- Prevention Avoiding placing clamp directly on the margin Remove permanently cemented crown before treatment The rubber dam is released from the wings and positioned with the rubber between the jaws of the retainer and the restoration to provide a buffer. Specialized crown pliers can be used to remove restorations Remove crown with special device called Metalift crown and bridge system Ultrasonic Vibration
- Metalift crown and bridge system
Access Cavity Perforations Happens during the search for canal orifices. Recognition
- Can occur either peripherally through the sides of the crown or through furcation.
- If the access cavity perforation is
- Above PDL attachment- Presence of leakage into the access cavity is often the first indication of an accidental perforation.
- Into PDL Bleeding into the access cavity is often the first indication of an accidental perforation. Cause
- Failure to identify the angle of the crown to the root and the angle of the tooth in the dental arch.
- Access through crowned teeth.
- Maxillary lateral incisors and mandibular first premolars.
- Using a surgical length bur
- Misidentification of canals Correction
- Coronal walls above the alveolar crest – can be repaired intracoronally without surgical intervention.
- Perforations into periodontal ligament – should be done as early as possible to minimize injury to the tooth’s supporting tissues.
- If the fracture is more extensive, the tooth may not be restorable and needs to be extracted. Prognosis
- Less likely than for an intact tooth and the outcome is unpredictable.
- Crown infractions may lead to vertical root fractures Instrumentation Related Mishaps Ledge Formation
- DEFINITION:
- The Glossary of Endodontic Terms of the American Association of Endodontists defines a ledge as “an artificially created deviation of the root canal wall that prevents the passage of an instrument to the apex of an otherwise patent canal
- A deviation from the original canal curvature without communication with the PDL, resulting in a procedural error is termed ledge formation or ledging.
- Etiology According to Jafarzadeh and Abbott, the common 14 causes for ledging of a canal are as follows:
- Not extending the access cavity sufficiently to allow adequate access to the apical part of the root canal
- Complete loss of control of the instrument if the endodontic treatment is attempted through 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 a sequential order
- Rotating the file at the working length (i.e., overuse of a reaming action)
- Inadequate irrigation and/or lubrication during instrumentation
- Overrelying on chelating agents
- Attempting to retrieve broken instruments
- Removing root filling materials during endodontic retreatment
- Attempting to prepare calcified root canals
- Inadvertently packing debris in the apical portion of the canal during instrumentation (i.e., creating an apical blockage) Initial Negotiation/Bypassing the Ledge
- A rubber stopper with a directional indicator is valuable in this situation because the indicator can be pointed in the same direction as the bend placed in the instrument.
- A slight rotation of the file combined with a “pecking” motion can often help advance the instrument to the full working length of the canal. Whenever resistance to negotiation is met, the file should be retracted slightly, rotated, and then advanced again with the precurved tip facing in a different direction.
- This action should be repeated until the file consistently bypasses the ledge.
- In some cases, a longer instrument is required to reach the ledge present in the radicular third of a long canal. The microexplorer (fig.) is used to explore the original canal and penetrate a narrow canal beyond the ledge. They can be used in sequence to reduce or remove the ledge prevention Root Perforations Perforation might occur during preparation of access cavities, post space or may occur as a result of extension of internal resorption into periradicular tissues. Perforations in all locations can be caused by 2 main errors:
- Creating a ledge in the canal wall during initial preparation and perforating through the side of the root at the point of obstructions / 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 instrumentati Considerations influencing perforation repair:
- Recognition
- Sudden appearance of blood.
- Magnification with either loupes, an endoscope, or a microscope is very useful.
- Confirmed : place a small file and take a radiograph of the tooth.
- Correction
- Hemostatics to control bleeding.
- Small area : sealed from inside the tooth
- Large area : seal from inside, then surgical repair Materials used:
- Calcium Hydroxide, Collagen, Calcium Sulfate, Freeze-dried Bone, MTA
- Where esthetics is a concern, a calcium sulfate barrier along with composite restoration is generally used.
- 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 because of its many desirable attributes.
- Prognosis
- Usually Reduced
- Surgical correction is required if a lesion / symptoms develops depends on: Size Location Length of time Ability to seal Accessibility to main canal Existing periodontal condition
- Prevention
- Reviewing each tooth’s morphology prior to entering its pulp space.
- Thorough examination of pre-operative radiographs is the paramount step to avoid this mishap.
- Checking the long axis of the tooth and aligning the long axis of the access bur with the long axis of the tooth - tipped tooth.
- Following principles of access cavity preparation, adequate size and location, both permitting direct access to the root canals.
- Mid-Root Perforation
- Cause
- Perforating when a ledge has formed •
- Along the inside curvature of the root as the canal is straightened out - “Canal Stripping” (Ex: Distal wall of the mesial root of the mandibular first molar)
- Difficult access
- Limited visibility
- Uncertainity of moisture free environment
- Recognition
- Stripping is easily detected by the sudden appearance of hemorrhage in a previously dry canal.
- Sudden complaint by the patient.
- Paper points placed into the canal
- Apex locators
- Correction
- By nature of occurrence, these defects are ovoid in shape and typically represent relatively large surface area to seal.
- Access to midroot perforation is most often difficult, and repair is not predictable.
- Successful repair depends upon the adequacy of the seal established by the repair material.
- The repair should be immediate, to protect the perforated site from saliva and other contaminants.
- Barrier material of choice is MTA.
- Two-step method: canals obturated and then defect is repaired surgically
- Apical Perforation
- CAUSE
- Straight canal : Inaccurate WL & instrumenting beyond apex
- Curved canal : Ledging, Apical Transportation or Apical Zipping Recognition
- In case of failing furcation repairs,
- Bicuspidation
- Hemi-Section
- Intentional Replantation can be considered as treatment options. Instrument Separation
- Separation of endodontic instruments within the root canal is an unfortunate occurrence that may hinder root canal procedures and affect the outcome.
- Files & Reamers – most commonly involved
- Separation rates of stainless steel (SS) instruments have been reported to range between 0.25% and 6% (8–11), the separation rate of NiTi rotary instruments between 1.3% and 10.0%. Cause 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. Recognition
- Loss of WL
- Shortened instrument
- Radiographic confirmation Correction
- There are three approaches to treatment.
- Attempt to remove the instrument
- Attempt to by-pass it
- Prepare and obturate up to the separated segment. It will vary depending upon the location and nature of the broken instrument Factors influencing broken instrument removal Cross section diameter of the canal
Length of the canal Curvature of the canal Root morphology-thickness of dentin Depth of external concavities Area of breakage
- If one third of the overall length of an obstruction can be exposed and /or Instrument that lie in the straight portion of the canal : Retrieval Is Possible.
- Instrument lies partially around the canal curvature and if access can be established to its most coronal extent : Removal is Difficult But Still Possible.
- If the entire segment of the broken instrument is apical to the curvature if the canal and safe access cannot be accomplished : Removal Impossible
- Type of the material 1. SS files :
- Tend to be easier for removal because they do not further fracture during the removal process 2. NiTi instruments :
- May explode and break again deeper within the canal because of heat buildup caused by ultrasonic devices.
- Retrieval Techniques
- Chemical Solvents
- The use of EDTA has been suggested as a method of softening root canal wall dentin around separated instruments, facilitating the placement of files for the removal of the fragment.
- Other chemicals such as iodine trichloride, nitric acid, hydrochloric acid, sulfuric acid, crystals of iodine, iron chloride solution, nitrohydrochloric acid, and potassium iodide solutions have historically been used to achieve intentional corrosion of metal objects. Mini Forceps
- In the presence of sufficient space within the root canal system, an instrument separated in a more coronal portion of the root canal can be grasped and removed by using forceps such as Steiglitz forceps (Union Broach, York, PA) ,
- Peet silver point forceps (Silvermans, New York, NY) ,
- or Endo Forceps (Roydent, Johnson City, TN).
- Braiding of Endodontic Files
- A Hedstrom or K-type file(s) can be inserted into the root canal to engage with the fragment and then withdrawn.
- This method can be effective when the fragment is positioned deeply in the canal and not visible and the clinician is relying on tactile sense, or the fragment is loose but cannot be retrieved by using other means.
- Wedged instruments in Coronal Third
- Masseran KIT :
- Useful for removing metallic objects from root canals.
- It contains a series of tubular trephine drills, and two sizes of tubular excavator. Technique: First creating a space in the root canal around the coronal 2 mm of the metallic object, so that the excavator tube will pass over it. Then the excavator plugger, a locking rod in the tube is screened down, locking the metallic object against a knurled ring in the tube wall.
This mechanism provides adequate retention for removal of most metallic object and instruments.
- Instrument Retrieval System (IRS)
- Endo extractors :
- They grasp the instrument with cyanoacrylate and not by friction.
- Endo safety system:
- Also uses trephine burs.
- These trephines are smaller in diameter and the extractors use different mechanisms for grasping instruments Ultrasonic instruments Future Techniques
- Laser Irradiation. The Nd:YAG laser has been tested recently in laboratory studies for removal of separated instruments.
- It is claimed that minimum amounts of 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: (1) the laser melts the dentin around the fragment and then H-files are used to bypass and then remove it, and (2) the fragment is melted by the laser Canal Blockage / Blockout
- Cause
- Files compact apical debris (dentin chips)
- Fibrous blockage (tissue debris)
