Management of endodontic failures Flashcards
Endodontic outcome aim (3)
The aim of endodontic treatment is to prevent or cure
periapical periodontitis
When assessing outcomes of endodontic treatment we
are assessing whether we have met this aim
Ideally, the outcome should be the absence, or in cases
where there were signs of preoperative periapical
periodontitis, the resolution of periapical periodontitis
after endodontic treatment
Outcome criteria - strict vs loose (4)
Strict criteria:
This requires no symptoms , no clinical signs of disease, and no periapical radiolucencies for endodontic treatment to be deemed a success.
This is ideal, but may be unrealistic.
Loose criteria:
This requires no symptoms, no clinical signs of disease and a decrease (or at least no increase) in the size of the preoperative periapical radiolucency for endodontic treatment to be deemed a success.
This is a more realistic approach
Outcome criteria - survival (3)
A more pragmatic approach may be to use ‘survival’ as
the outcome criteria
This is defined as the tooth being present in the arch,
asymptomatic and functional (ie there may still be
clinical and radiographic signs of pathology, which
may even be worsening)
This is useful for comparing to the survival rate of
implants (to ‘level the playing field’)
Better terms to describe outcome criteria than success and failure (4)
Favourable Uncertain Unfavourable This complies with the current European Society of Endodontology guidelines
What do the studies say about the outcome of endodontic treatment? (4)
These generally have different study designs and outcome criteria, and
include systematic reviews and prospective studies
Some of the most recent and well recognised are the studies undertaken at the Eastman Dental Hospital by Paula Ng
Depending on the outcome criteria and type of study success rates of
around 85% were reported
Depending on the case outcomes of up to 95% can be achieved
Which factors affect endodontic treatment outcome? (4)
Despite the heterogeneity in study outcomes, there is
good evidence to support three main factors affecting
endodontic outcome:
Preoperative status of the periapical tissues
Quality of the root canal filling
Quality of the coronal restoration
Preoperative status of the periapical tissues (4)
The outcome is likely to be more favourable when the pulp is vital, has pulpitis or is necrotic but uninfected
Probability of success can be in the region of 95% in these cases
In teeth with signs of periapical periodontitis (i.e. a PA radiolucency on a radiograph) success reduces to around 85%, probably because the root canal is more heavily infected
The likelihood of a successful outcome appears to be reduced further when the PA radiolucency is larger than 5mm in diameter
Quality of the root canal filling (5)
Endodontic treatment is more likely to be successful
when the root canal filling is satisfactory
This is defined as extending to within 2mm of the
radiographic apex, and well compacted
The likelihood of a successful outcome is lower when :
The root filling is overextended/long
The root filling is underextended/short
The root filling contains voids
Quality of the coronal restoration (4)
Endodontic treatment is more likely to be successful when the quality of the coronal restoration is satisfactory
The restoration should have no marginal deficiencies, defects or
recurrent caries which can act as routes for bacteria to re-infect the root canal
Some studies have indicated an increased success rate when a fullcoverage coronal restoration is placed (e.g. a crown) following
endodontic treatment
Whilst placing a crown is often desirable following completion of
endodontic treatment to improve coronal seal and structural durability,
each tooth should be assessed on its own merits regarding whether to
place a crown or a direct restoration
Assessing endodontic outcome (3)
Patient should be assessed 9-12 months following completion of endodontic treatment for a clinical and radiographic assessment
Patient may be reviewed earlier if they are
experiencing continued symptoms, but a radiograph
should not usually be taken unless further developments are suspected (eg root fracture etc)
Depending on the outcome at review, patients may need to be reviewed for up to four years
The review apt should include (3)
Assessment of the patient’s symptoms
Clinical examination
Radiographic examination
Patient symptoms (3)
Patients should be asked regarding pain, swelling and/or loss of
function
However, a lack of symptoms does not always prove a favourable outcome – a clinical and radiographic examination are also required
Continued discomfort/pain may be due to persistent periapical infection, but also due to other reasons:
Occlusal interferences
Food trapping in the area
Tooth fracture
Neurogenic pain
Non-odontogenic pain e.g. sinusitis, TMD, atypical facial pain
Neurogenic pain (5)
Nerves around tooth become sensitised even after infection has cleared Low grade On and off Nothing specific brings it on Root treatment will not help They need to go to a pain clinic Medication could help
Clinical examination (7)
Presence/absence of a sinus tract or swelling
Tenderness to palpation in the sulcus and soft tissues
Tenderness to percussion of the tooth
Presence of tooth fractures
Presence of dental caries
Periodontal status: probing depths and mobility
Quality of the coronal restoration
Radiographic examination (6)
Quality of the root filling
Presence/absence of a periapical radioluncency
Size of the PA radiolucency (if present) and comparison to the preoperative PA lesion (increase, decrease, no change in size)
Quality of the coronal retoration
Presence of caries
Periodontal condition
CBCT has been shown to have superior accuracy in detecting periapical pathology, however, this would only be indicated in
specific situations e.g. persistent pain with no signs on a conventional radiograph
Criteria for a favourable outcome (4)
For the outcome of endodontic treatment to be
deemed favourable, the following criteria should be
observed:
The patient is symptom-free
The tooth is functional
Clinically, the associated tissues are healthy
Radiographically, the associated periapical tissues
appear healthy
Criteria for an uncertain outcome (3)
In certain cases the clinician may not be able to clearly
classify the outcome of treatment as favourable or
unfavourable:
There are no signs or symptoms, however:
Radiographically, the periapical radiolucency has
persisted (remained the same size or only reduced in size) within the four-year assessment period
Criteria for an unfavourable outcome (4)
The patient is complaining of symptoms, e.g. pain, swelling
The endodontically treated tooth is not functional, e.g. the patient avoids eating on it
Clinically, there are signs of infection, e.g. sinus tract, swelling
Radiographically:
A new periapical radiolucency has developed
The periapical radiolucency has increased in size
Radiographically, the periapical radiolucency has persisted (remained
the same size or only reduced in size) at or after the four-year assessment
period
When to place a definitive restoration (3)
Placing a definitive restoration soon after completion of endodontic treatment will improve coronal seal and
structural durability
Studies have shown that placing an indirect
restoration increases the prognosis for the tooth,
however, each tooth should be assessed on its own
merits
Wait until clinical signs and symptoms have resolved
before placing an indirect restoration but do not feel
obliged to wait until there is radiographic resolution of
the lesion
Why does endodontic treatment fail? (4)
Intraradicular infection
Persistent infection: residual microbes left within the root canal
following the endodontic treatment
Secondary infection: Microbes which have re-entered the canal
following endodontic treatment (coronal leakage, fractures etc)
Extraradicular infection
Periapical actinomycosis, displacement of infected dentine etc
True cysts
Apical true cysts are self-sustaining and do not heal following satisfactory root canal treatment
Foreign body reaction
Foreign bodies (e.g. gutta percha) can compromise healing
Recognising post-treatment disease (2)
As with assessing outcome of your own endodontics, a
thorough assessment of the patient’s symptoms, clinical
signs and radiographic assessment is essential
If you did not undertake the endodontic treatment
yourself, you also need to ascertain a history of the previous
endodontic treatment:
Where was it performed?
When was it done?
What was the original diagnosis?
Did the original treatment remove the symptoms initially?
What techniques were used and how long did it take?
Management of endodontic failures (3)
Once it has been decided that a root treatment has failed,
options regarding future management need to be
considered
Management of endodontic failures can be complex from
both a treatment planning perspective and treatment
perspective
If endodontic treatment has failed there are four main
options:
No treatment (monitoring)
Extraction
Endodontic retreatment
Apical surgery
No treatment (monitoring) (4)
When the outcome is not favourable according to strict
criteria but the tooth is stable enough to warrant review,
rather than intervention
For example, the tooth may be symptom-free but have a
non-healing periapical radiolucency
Monitoring will avoid the risks associated with reintervention
The patient should be advised:
The tooth will require regular review
To return if signs/symptoms develop
That an acute flair up may occur at any time
Extraction (5)
Extraction is the quickest way to deal with endodontic
disease
Consider extraction when:
The patient does not wish to have further treatment and
monitoring is not an option
Teeth where the restorability is doubtful
Non-functional teeth/teeth with no strategic value
Teeth with untreatable disease e.g. root fracture,
advanced periodontal bone loss etc
Endodontic retreatment (5)
The treatment of choice when post-treatment disease is
present and the patient is keen to save the tooth
Only consider if the tooth is restorable
Even if the previous obturation looks adequate, you do not
know how well the tooth was disinfected, whether rubber
dam was used etc etc
The goal of endodontic retreatment is the same as initial
treatment: eradicate microbes and provide a good apical
and coronal seal
When undertaken properly, success rates can be nearly as
high as primary treatment (83% vs 80%)
Endodontic retreatment (3)
Prior to initiating retreatment, a patient should be
advised that:
During treatment the tooth may be deemed
unrestorable e.g. discovery of a catastrophic fracture,
gross caries etc
Root canal retreatment is complex and there are risks
e.g. perforation, which may render the tooth
unrestorable or at least reduce the prognosis
It may not be possible to fully instrument canals if they
are blocked etc and this will affect the prognosis
Surgical endodontics (7)
Surgical endodontics should only be carried out when it is not possible (or pragmatic) to carry out root canal retreatment
Indications for surgical endodontics:
Where root canal retreatment would have an unfavourable outcome
Obstructions within the canal which cannot be removed/negotiated
with orthograde treatment
Teeth with long/wide posts which risk root fracture if removal is attempted
Perforations which require surgical repair
Investigative procedures (e.g. biopsies, confirmation of root fractures etc)
Extraradicular infection and true cysts
The canal contents which require removal can include (5)
Gutta percha Endodontic posts Thermafil carriers Silver points Fractured instruments etc -in addition, repair of iatrogenic perfrations may be required
Removal of gutta percha (5)
There are a variety of techniques for removing gutta
percha:
Gates glidden burs followed by hand files (K-files and H-files)
Retreatment rotary NiTi files
Solvent technique
Combinations of the above
Gates glidden burs and hand files (7)
Gates glidden burs can be used to remove the coronal GP
Hand files can then be used to remove the apical GP
Hedstrom files are useful for gripping GP by engaging it in its cutting flutes
Proceed cautiously!
Check files regularly for distortion
Ideally GP should always be visible to ensure you remain centred within the canal
Tactile sensation of GP feels more ‘rubbery’ (obviously!) compared to dentine
Retreatment rotary files to remove GP (3)
Some systems (e.g. Protaper) produce files which are specially designed to remove GP
They are more resistant to fracture and designed to
move dislodged GP in a coronal direction
Never use Protaper SX, S1 or S2 files to remove GP –
they are too fragile at the tip
Solvent technique to remove GP (4)
Certain solvents can be used to soften GP aiding its
removal
Examples include chloroform, xylol, eucalyptus oil and orange oil
We use chloroform in the hospital but there are some
COSHH limitations
Should be used sparingly, ideally following bulk
removal with other instruments due to the tendency for it to become smeared everywhere!
Combination of techniques to remove GP (3)
Most of the time a combination of techniques is used:
Gates glidden or rotary NiTi to remove coronal GP
Rotary NiTi or hand files to remove apical GP
Using solvents as required, particularly to help remove the final GP in the apical portion
Removal of endodontic posts (5)
Metal endodontic posts can be
removed using a number of
techniques
‘Trephining’ around the post using an
ultrasonic tip or specialised kit (Masserann)
Using ultrasonic to break the cement lute
Grabbing the post with fine forceps
Specialised endodontic post removal kits
(e.g.Ruddle, Egler etc)
Combinations of the above
Removal of endodontic posts (6)
The first stage is to remove the crown on the tooth and
then remove the core material, leaving only the post sticking out from the canal
Cast cores need to be reduced carefully, so the core is reduced to the post width extending out of the canal to give
something to grip to
The appropriate technique or combination of techniques
can then be used to loosen the post
Threaded posts can often simply be unscrewed
Fibre posts are usually bonded in and are
difficult to loosen
The most effective way to remove them is to
use a diamond bur or ultrasonic to remove the
post by drilling down through the middle of
the post
Removal of Thermafil carriers (6)
Plastic Thermafil carriers can be challenging to
remove
They have a groove down them which is meant to
be engaged by a file prior to removal, however this
is often ineffective
Use hand files/rotary files to remove coronal GP
(maybe using a solvent) then try to ‘grab’ the
carrier
The ‘braiding’ technique can be very effective –
braid 2 hand files around the carrier and exert a
pull in the coronal direction
Once the carrier is removed the remaining GP can be removed using the previously described
methods
Thermafil have recently released new carriers made
from GP which are easier to remove
Removal of silver points (4)
Silver points are not commonly found
nowadays
It is however important to recognise them
on a radiograph
Silver points were discovered to corrode over
time and they can therefore disintegrate
during removal
Techniques to remove them include troughing around them with ultrasonics, trephining with a Masserann kit, grabbing them with fine forceps and using the
braiding technique
Removal of fractured instruments (3)
Fractured instruments can be very
challenging to remove
If an instrument cannot be removed
you can attempt to bypass it
Removal is attempted by first achieving
good access and vision (microscope
essential!)
Ultrasonics or a modified gates glidden bur
can be used to create a ‘staging platform’
A combination of techniques (ultrasonics,
hand files, Masseran kit etc) can be used to
attempt to loosed and remove the fragment
If successfully removed the remainder of the
endodontic treatment can be completed
conventionally
Success in removal of fractured instruments depends on (4)
Where the instruments has fractured
What type of instrument it is
How long the fragment is
How accessible it is
Repair of perforations - prognosis depends on (4)
The size of the perforation
The location of the perforation
The condition of the remaining tooth
How infected it is
Repair of perforations (3)
Perforations indicate a poor prognosis for
the tooth
Perforations can be repaired internally or
externally
MTA or biodentine are the materials of
choice for repairing perforations
Options for managing patients when you’re in practice (3)
Don’t automatically assume that because it is endodontic
retreatment it is ‘specialist’ and therefore beyond your
capabilities
However, consider your own experience and limitations before
embarking on treatment
Assess the case – a ‘thready’ obturation or single cone may be
relatively easy to remove
If you decide to refer a patient, you may have the following options (3)
Refer to a local dentist who is either a specialist or has a
‘special interest’ in endodontics, however, this is likely to be private
Refer to a local hospital with an endodontic service,
however, not all hospitals with a restorative service
accept patients for endodontics
Remember, CCDH does not accept referrals for molar
endo (even for retreatment)
