25/02/2014
Asalaam Alekkum
Dr Gaurav Garg, Lecturer
College of Dentistry, Al Zulfi, MU
 Endodontic mishaps or procedural accidents are
those unfortunate occurrences that happen during
treatment, some owing to inattention to detail, others
totally unpredictable.
 Recognition
 Correction
 Re-Evaluation
 Recognition:
 It may be by radiographic or clinical observation or as a
result of a patient complaint; for example, during
treatment, the patient tastes sodium hypochlorite owing to
a perforation of the tooth crown allowing the solution to
leak into the mouth.
 Correction:
 may be accomplished in one of several ways depending
on the type and extent of procedural accident.
 Unfortunately, in some instances, the mishap causes such
extensive damage to the tooth that it may have to be
extracted.
 Re-evaluation:
 Re-evaluation of the prognosis of a tooth involved in
an endodontic mishap is necessary and important.
 This may affect the entire treatment plan and may
involve dentolegal consequences.
 Dental standard of care requires that patients be
informed about any procedural accident.
 The following suggestions can help in
establishing good patient communication:
 Inform the patient before treatment about the possible
risks involved
 When a procedural accident occurs, explain to the
patient the nature of the mishap, what can be done to
correct it, and what effect the mishap may have on the
tooth’s prognosis and on the entire treatment plan.
 Referral to a specialist
ENDODONTIC MISHAPS
Access related
1. Treating wrong
tooth
2. Missed canals
3. Damage to
existing
restoration
4. Access cavity
perforations
5. Crown fractures
Instrumentation
Related
Obturation related
1. Ledge formation
1. Over- or
underextended
root canal fillings
2. Cervical canal
perforations
3. Midroot
perforations
4. Apical
perforations
5. Separated
instruments and
foreign objects
6. Canal blockage
Miscellaneous
1. Post space
perforation
2. Nerve paresthesia
2. Irrigant
related
3. Vertical root
fractures
3. Tissue
emphysema
4. Instrument
aspiration
and ingestion
 Recognition:
Continued symptoms after treatment
b. Isolating wrong tooth- evident after
removal of rubber dam
a.

•
•
Correction:
Inform the patient
Appropriate treatment of both teeth:
the one incorrectly opened and the one
with the original pulpal problem.
 Prevention:
 Before making a definitive diagnosis,
obtain at least three good pieces of
evidence supporting the diagnosis
such as:
1.
2.
3.
Radiographic evidence
Electric/ Thermal pulp tests
G.P. point tracing in case of
draining sinus
 If the diagnosis is tentative, apply
the remedy of "tincture of time” to
allow signs and symptoms to
become more specific.
 Mark the tooth before applying
rubber dam.
1
2
3
3
 Recognition:
 Recognition of a missed canal can occur during
or after treatment.
 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
 In addition to standard radiographs for the
determination of missed canals, computerized
digital radiography has increased the chances of
locating extra canals by enhancing the density
and contrast and magnifying the image.
 Magnifying loupes, the microscope, and the
endoscope may be used to clinically determine
the presence of additional canals
 Correction:
 Re-treatment is appropriate and should
be attempted before recommending
surgical correction.
 Prognosis:
 A missed canal decreases the prognosis
and will most likely result in treatment
failure.
 In some teeth with multicanal roots, two
canals may have a common apical exit.
 As long as the apical seal adequately
seals both canals, it is possible that the
bacterial content in a missed canal may
not affect the outcome for some time.
II
IV
 Prevention:
 Locating all of the canals in a multicanal
tooth
 Adequate coronal access allows the
opportunity to find all canal orifices.
 Additional radiographs taken from mesial
and/or distal angles.
 Knowledge of root canal anatomy &
morphology.
 Assuming at the outset that certain teeth
have roots with multiple canals and
diligently searching for those canals is a
prudent preventive procedure.
 In preparing an access cavity through a
porcelain or porcelain-bonded crown, the
porcelain will sometimes chip, even when the
most careful approach using water-cooled
diamond stones is followed.
 Correction:
 Minor porcelain chips can at times be repaired
by bonding composite resin to the crown.
 However, the longevity of such repairs is
unpredictable.
 Prevention:
 Do not Place a rubber dam clamp
directly on the margin of a porcelain
crown.
 An alternative to prevent damage to an
existing permanently cemented crown is
to remove it before treatment by using
special devices such as the Metalift
Crown and Bridge Removal System
(Classic Practice Resources, Inc, Baton
Rouge, La.)..
 Perforation: Undesirable
communications between the pulp
space and the external tooth surface
 They may occur during preparation
of the access cavity, root canal space,
or post space.
 Recognition:

If the access cavity perforation is above the
periodontal attachment, the first sign of the presence
of an accidental perforation will often be the presence
of leakage: either saliva into the cavity or sodium
hypochlorite out into the mouth, at which time the
patient will notice the unpleasant taste.
 When the crown is perforated into the periodontal
ligament, bleeding into the access cavity is often the
first indication of an accidental perforation.
 To confirm the suspicion of such an unwanted
opening, place a small file through the opening and
take a radiograph; the film should clearly demonstrate
that the file is not in a canal.
 In some instances, a perforation may initially be
thought to be a canal orifice; placing a file into this
opening will provide the necessary information to
identify this mishap
 Correction:
 Perforations of the coronal walls above the
alveolar crest can generally be repaired
intracoronally without need for surgical
intervention
 Perforations into the periodontal ligament,
whether laterally or into the furcation,
should be done as soon as possible to
minimize the injury to the tooth’s
supporting tissues.
 It is also important that the material used
for the repair provides a good seal and does
not cause further tissue damage.
 Several materials have been recommended
for perforation repair: Cavit, amalgam,
calcium hydroxide paste, glass ionomer
cement, tricalcium phosphate, MTA etc.
 Prior to repair of a perforation, it is
important to control bleeding, both to
evaluate the size and locations of the
perforation and to allow placement of
the repair material.
 Calcium hydroxide placed in the area
of perforation and left for at least a
few days will leave the area dry and
allow inspection of perforation.
 Mineral trioxide aggregate, in contrast
to all other repair materials, may be
placed in the presence of blood since
it requires moisture to cure.
 Prognosis:
 It is generally be downgraded.
 Depends on:
 Size
 Location
 Time
 Accessibility & Sealing
 Existing periodontal conditions
 Generally, it can be said that the sooner repair is
undertaken, the better the chance of success.
 Surgical corrections may be necessary in refractory
cases.
 Prevention:
 Thorough examination of diagnostic preoperative
radiographs
 Aligning the long axis of the access bur with the long axis
of the tooth can prevent unfortunate perforations of a
tipped tooth.
 The presence, location, and degree of calcification of the
pulp chamber noted on the preoperative radiograph
 Perforations can also often be associated with an
inadequate access preparation.
 Follow principles of access cavity preparation: adequate
size and correct location, both permitting direct access to
the root canals.
 A thorough knowledge of tooth anatomy, specifically
pulpal anatomy, is essential for anyone performing root
canal therapy.
Safe ended bur
 Crown fractures can happen
when the patient chews on the
tooth weakened additionally by
an access preparation.
 Recognition of such fractures
is usually by direct observation.
 Treatment:
 Crown fractures usually have to be treated by
extraction unless the fracture is of a “chisel type” in
which only the cusp or part of the crown is involved.
 In such cases, the loose segment can be removed and
treatment completed.
 Prognosis:
 For a tooth with a crown fracture, if it can be
treated at all, is likely to be less favorable than for an
intact tooth, and the outcome is unpredictable.
 Crown infractions may spread to the roots, leading to
vertical root fractures.
 Prevention:
 Reduce the occlusion before working
length is established.
 In addition to preventing this mishap, it
also will aid in reducing discomfort
following endodontic therapy.
 Orthodontic bands and temporary
crowns can be applied before endodontic
treatment.
4/03/2014
 Causes:
 Failure to get straightline
access
 Using too large instruments
in curved canals
 Recognition:
 Ledge formation should be suspected
when the root canal instrument can
no longer be inserted into the canal
to full working length
 This feeling of the instrument point
hitting against a solid wall
 Radiograph of the tooth with the
instrument in place will provide
additional information.
 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.
 The curved tip should be
pointed toward the wall
opposite the ledge.
 Do not apply force
 Prevention:
 The best solution for ledge formation is
prevention.
 Accurate interpretation of diagnostic
radiographs should be completed before the
first instrument is placed in the canal.
 Awareness of canal morphology is
imperative throughout the instrumentation
procedure.
 Use of flexible instruments (Ni-Ti) with non
cutting tip
 Finally, precurving instruments and not
“forcing” them is a sure preventive measure.
 Radicular perforations can be identified as
either cervical, midroot, or apical root
perforations.
 Perforations in all of these locations may be
caused by two errors of commission:
 (1) 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
 (2) 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
overinstrumentation (canal “stripping”).
 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.
 Recognition by the sudden appearance
of blood, which comes from the PDL.
 Can be managed by sealing with MTA
 Fair prognosis if sealed properly
 Tend to occur mostly in curved canals
 Detected by the sudden appearance of
hemorrhage in a previously dry canal or by
a sudden complaint by the patient.
 A paper point placed in the canal can
confirm the presence and location of the
perforation
 Repair is difficult due to limited access
 Prognosis is not good and may lead to
fractures and microleakage due to
improper sealing
 Prevention by Anticurvature filing and use
of flexible instruments
 Recognition:
 Patient suddenly complains of pain
during treatment
Apical transportation
 Canal becomes flooded with
hemorrhage
 Tactile resistance of the confines of
the canal space is lost
Apical zipping
 Correction:
 Renegotiation of apical canal segment,
considering perforation site as new apical
opening and obturation of both by
Thermoplastisized GP
 Surgery in case of periapical lesion and
extensive damage
 Re-establish new working length in case of
apical foramen perforation
 Creating an apical barrier using MTA
 Prognosis is better than coronal and midroot
perforation
 Endodontic files & reamers (most common)
 GG drills
 Lentulospirals
 Fragments of amalgam fillings
 Tooth picks
 Pencil leads
 Pins
 Tomato seeds
 Causes:
 Applying excessive force
 Extreamely curved & constricted
canals
 Fatigued and stressed instruments
 Failure to get a smooth glide path
 Correction:
 Try to remove fractured instrument
 Sometime a H-file may be useful
 Fine ultrasonic instruments can be useful
under proper illumination and
magnification
 If failed to retrieve:
 Try to bypass it carefully using small file or
reamer
 If not bypassed treat the rest of the canal
portion
 Consider surgery in failure cases and if
fragment extends past the apex
 Prevention:
 Establish straightline access
 Do not force the instrument
 Establish a glide path
 Do not skip sizes
 Do not use fatigued or stressed instruments
 Use copious irrigation
 Use of a canal lubricant
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1
 Blockage of canal due to compacted
dentinal debris or pulp tissue
 Recognition occurs when the
confirmed working length is no
longer attained
 Correction:
 Recapitulation
 Copious irrigation
 Use of canal lubricants
Blocked canal
 The apical termination of the filling
material ideally should be just short
of the radiographic apex (1-2 mm)
 If extruded beyond apical limit-
Overextension
 If short than apical limit-
Underextension
 Causes:
 Apical perforation
 Too much condensation force
 Loss of apical constriction- open
apex, resorption etc.
 May result in treatment failure by:
 Irritation from filling material
 Leakage
 Compression of neurovascular bundle
& neurotoxicity
 Causes:
 Incorrect working length
 Failure to fit master cone up to
working length
 Improper canal preparation
particularly in apical part
 May result in treatment failure by:
 Persistent infection
 Reinfection and apical percolation
of tissue fluids
 Recognition:
 By a post-treatment radiograph
 Correction:
 Retreatment
 Periapical surgery
 Prevention:
 Accurate working length
 Modification of obturating techniques
 Creation of apical stop in case of open
apex- using MTA
 Taking radiograph during initial phases
of obturation to allow corrections
 Causes:
 Overinstrumentation
 Overextension of obturating material
 Nerve injury by formaldehyde containing pastes
 Prevention is the best remedy
 Can occur during:
 Instrumentation
 Obturation
 Post placement
 Due to application of high apical/lateral
forces & Thin, weak canal walls
 Recognised by sudden crunchy sound,
deep localized periodontal pocket,
Teardrop shaped radiolucency
 Poor prognosis
 Causes:
 Misdirected drills/burs in post space preparation
 Recognition by bleeding/ radiograph
 Corrected by sealing/repair
 Prevention:
 Radiographic interpretation of canal anatomy
 Better to prepare post space during time of obturation
 Better to remove gutta percha with hot instrument rather than drills
 Sodium hypochlorite accident- most
common
 Immediate swelling, pain, ecchymosis
 Severity of symptoms depends on type,
amount, concentration & toxicity of irrigant
 Treatment:
 Symptomatic treatment with analgesics &
antibiotics
 Ice pack application initially followed by
warm saline soaks from next day
 In severe cases- hospitalization & monitoring
 Prognosis:
 Mostly favorable if treated immediately
 Otherwise paresthesia, scarring and muscle
weakness may occur
 Prevention:
 Do not force irrigant
 Irrigating needle should not bind in the canal
 Use Special irrigating needles such as side vent
needles
 Collection of gas/air in to subcutaneous/
periradicular tissues
 The common etiologic factor is compressed air
being forced into the tissue spaces- during canal
preparation or surgical procedures
 Recognition by rapid swelling, erythema, and
crepitus
 Treatment: Palliative care and observation
 Prevention:
 Use paper points to dry the canal
 Use slow/high speed handpiece during surgery
which do not direct jets in to the surgical site
 Causes:
 Failure to use Rubber Dam
 Recognition:
 Patient’s symptoms
 Chest & Abdomen Radiographs
 Management:
 Immediately hospitalized the patient
 Prevention:
 Use rubber dam strictly
 Attaching floss to the clamps, files, reamers.
 Endodontics; 2005; Ingle & Bakland
 Pathways of the pulp; 2000; Stephen Cohen