Management of Endodontic Failures Flashcards

1
Q

What is the aim of endodontic treatment?

A

Prevent or cure periapical periodontitis

Outcome of endo treatment should be the absence or resolution of periapical periodontitis after endo tx

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2
Q

Outcome criteria of endo tx?

A

Strict success criteria

  • No symptoms, clinical signs of disease and no periapical radiolucencies for endodontic treatment to be deemed a success
  • Ideal but may be unrealistic

Loose success criteria

  • No symptoms, no clinical signs of disease and a decrease (or no increase) in the size of preoperative periapical radiolucency for endo treatment to be deemed a success
  • More realistic

Survival

  • Tooth being present in the arch, asymptomatic and functional (may be radiographic and clinical signs of pathology which may be worsening)
  • Useful for comparing the survival rate of implants

OR outcomes can be the european society of endodontology guidelines:

  • Favourable
  • Uncertain
  • Unfavourable
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3
Q

What affects the outcome of the endo tx?

A

Preop status of periapical tissues
Quality of root canal filling
Quality of coronal restoration

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4
Q

How does the preop status of the periapical tissues impact the outcome of endo tx?

A

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 periapical periodontitis success reduces to around 85% as the root canal is more heavily infected
Likelihood of success is further reduced when PA radiolucency is larger than 5mm in diameter

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5
Q

How does the quality of the root canal filling impact the outcome?

A

More likely to be successful when root canal filling is satisfactory = extending t within 2mm of the radiographic apex and is well compacted
Likelihood of a successful outcome is lower when:
- Root filling is overextended/long
- Root filling underextended/short
- Voids

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6
Q

How does the quality of the coronal restoration impact the outcome?

A

More likely to be successful when satisfactory coronal restoration
No marginal deficiencies, defects or recurrent caries which can act as routes for bacteria to reinfect the root canal
Some studies - increased success rate when a full coverage coronal restoration is placed after endo tx
Whilst placing a crown is often desirable following completion of endo tx to improve coronal seal and structural durability, each tooth should be assessed on its own merits regarding whether to place a crown or direct restoration

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7
Q

How to assess the outcome of the endo tx?

A

Pt should be assessed 9-12 months following completion of an endo tx for a clinical and radiographic assessment
Pt may be reviewed earlier if symptoms but a radiograph should not usually be taken unless further developments are suspected (e.g. root fracture)
Depending on review outcome, pts may need to be reviewed for up to 4 yrs

Assess pts symptoms
Clinical exam
Radiographic exam

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8
Q

How to assess the pt’s symptoms?

A

Ask about pain, swelling, loss of function

Lack of symptoms does not always mean favourable outcome - clinical and radiographic exam still needed

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9
Q

What may continued pain be due to?

A

Discomfort/pain due to persistent periapical infection or due to:

  • Occlusal interferences
  • Food trapping in area
  • Tooth fracture
  • Neurogenic pain
  • Non-odontogenic pain e.g. sinusitis, TMD, atypical facial pain - usually low grade on and off pain not brought on by anything specific = re-endo tx would not help
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10
Q

What to look at in the clinical exam when reviewing endo tx?

A

Presence/absence of a sinus tract or swelling
Tenderness to palpation in sulcus or soft tissues
Tenderness to percussion of tooth
Presence of tooth fractures and caries
Periodontal status: probing depths and mobility
Quality of coronal restoration

CBCT has superior accuracy in detecting periapical pathology but only indicated in specific situations e.g. persistent pain with no signs on a conventional radiograph

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11
Q

How to classify the outcome?

A

Depends on results of the pts symptoms, clinical outcome and the radiographic examination

  • Favourable
  • Uncertain
  • Unfavourable
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12
Q

Criteria for successful outcome?

A

Pt is symptom free
Tooth is functional
Radiograph - periapical tissues appear healthy

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13
Q

Criteria for uncertain outcome?

A

No signs or symptoms

Radiograph - periapical radiolucency stayed the same or gotten smaller within the 4 yr assessment period

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14
Q

Criteria for unfavourable outcome?

A

Pt complaining of symptoms
Endodontically treated tooth is not functional
Clinical signs of infection
Radiographically:
- New periapical radiolucency has developed
- Periapical radiolucency has increased in size
- Radiographically the periapical radiolucency has persisted (remained same size or only reduced in size) at or after the 4 yr assessment period

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15
Q

When to review endo tx depending on the outcome?

A

Favourable outcome = no further review appts
Uncertain outcome = annular review for up to 4 yrs
Unfavourable outcome = further tx recommended

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16
Q

When to place a definitive restoration?

A

Soon after completion of endo tx = improve coronal seal and structural durability
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

17
Q

Why does endodontic tx fail?

A

Intraradicular infection:

  • Persistent infection: Residual microbe left within the root canal following endo tx
  • Secondary infection - microbes which have re-entered the canal following endodontic tx (coronal leakage, fractures)

Extraradicular infection:
- Periapical actinomycosis, displacement of infected dentine

True cysts
- Apical true cysts are self sustaining and do not heal following satisfactory root canal treatment

Foreign body reaction
- Foreign bodies (e.g. GP) can compromise healing

18
Q

How to recognise post treatment disease?

A

Assess outcome of endo, pts symptoms, clinical signs and rad assessment
If not done endo tx yourself:
- Where was it performed
- When done
- What was the original diagnosis
- Did the original tx remove the symptoms initially
- What techniques were used and how long did it take

19
Q

How to manage endo failures?

A

No tx (monitor)
Extraction
Endo retreatment
Apical surgery

20
Q

When can a failed endo just be monitored?

A

When outcome is not favourable enough but the tooth is stable enough to warrant review rather than intervention
e.g. when tooth symptom free but has a non healing periapical radiolucency
Avoids the risks associated with re-treatment

Pt advised that

  • Tooth will require regular review
  • Return if signs/symptoms develop
  • That an acute flair up may occur at any time
21
Q

When to consider extraction?

A

Quickest way

Consider when:
Pt does not wish to have further tx and monitoring not an option
Restorability doubtful
Non-functional teeth/teeth with no strategic value
Teeth with untreatable disease e.g. root fracture, advanced perio bone loss

22
Q

When to do endo treatment?

A

When post tx disease is present and pt keen to save tooth
Only consider if tooth restorable
Even if previous obturation looks adequate, you do not know how well tooth was disinfected and if rubber dam was used
Goal of endo retreatment: eradicate microbes and provide a good apical and coronal seal
When undertaken properly, success rates nearly as high as primary tx (83% vs 80%)

23
Q

What to advise the pt prior to endo retreatment?

A

During the tx the tooth may be deemed unrestorable (e.g. discovery of a fracture, gross caries)
Root canal tx is complex and there are risks e.g. perforation which may render the tooth unrestorable or reduce the prognosis
May not be possible to fully instrument canals if they are blocked and this will affect the prognosis

24
Q

When should surgical endodontics be carried out?

Indications for surgical endodontics?

A

When not possible to carry out root canal retreatment

Indications:

  • Where root canal retreatment would have an unfavourable outcome
  • Obstructions in canal which cannot be removed/negotiated with orthograde tx
  • Teeth with long/wide posts which risk root fracture if removal is attempted
  • Perforations which require surgical repair
  • Investigative procedures (biopsies, confirmation of root fractures)
  • Extraradicular infection and true cysts
25
Q

How to remove GP?

A

GG burs followed by hand files

  • GG remove coronal GP
  • Hand files remove apical GP
  • Check files for distortion
  • Tactile sensation of GP feels more rubbery compared to dentine

Retreatment rotary NiTi files

  • Protaper files designed to remove GP
  • Files more resistant to fracture and designed to move dislodged GP in coronal direction
  • Never use protaper SX, S1, S2 to remove GP = too fragile at tip

Solvent techniques

  • Solvents can soften GP aiding its removal
  • Chloroform, eucalyptus oil and orange oil
  • Used sparingly

Combinations of above

  • GG or rotary to remove coronal GP
  • Rotary or hand files to remove coronal GP
  • Solvents to help remove final GP in apical portion
26
Q

How to remove endodontic posts?

A

Metal endo posts can be removed using a number of techniques

  • Trephining around post using ultrasonic tip
  • Ultrasonic to break cement lute
  • Grab posts with fine forceps
  • Specialised endo post removal kits
  • Combo of above

Firstly remove crown on tooth and then core material, leaving only the post
Cast cores need to be reduced carefully
Appropriate technique(s) to loosen post
Threaded posts can be unscrewed
Fibre posts are difficult to loosen - use a diamond bur to remove the post by drilling down through the middle of the post

27
Q

How to remove thermafil carriers?

A

Plastic thermafil carriers = use hand files/rotary to remove coronal GP then grab the carrier
OR
braid 2 hand files around the carrier and exert a pull in the coronal direction
Once carrier is removed, remove the remaining GP

28
Q

How to remove silver points?

A

Silver points rare
Corrode overtime and can disintegrate during removal
Trough around them with ultrasonics, trephining with a masserann kit, grabbing them with fine forceps and using the braiding techniques

29
Q

What does the success of removing a fractured instrument depend on?

A
Success depends on:
If instrument has fractured
What type of instrument it is
How long fracture is
How accessible it is 

If it cannot be removed, you can attempt to bypass it

30
Q

How to remove a fractured instrument?

A

Achieve good access and vision (microscope)

Ul

31
Q

How to remove a fractured instrument?

A

Achieve good access and vision (microscope)
Ultrasonics or a modified GG bur to create a staging platform
Combo of techniques can be used to loosen and remove fragment

32
Q

What does the prognosis of repairing perforations depend on?

A

Poor prognosis

Prognosis depends on

  • Size of perforation
  • Location of perforation
  • Condition of remaining tooth
  • How infected it is
33
Q

How to repair perforations?

A

Repaired internally or externally

MTA or biodentine

34
Q

Options for managing pts when in practice?

A

If you decide to refer:

  • Refer to local dentist who is a specialist or has special interests in endo - likely to be private
  • Refer to local hospital with endo service