Management of Endodontic Failures Flashcards
What is the aim of endodontic treatment?
Prevent or cure periapical periodontitis
Outcome of endo treatment should be the absence or resolution of periapical periodontitis after endo tx
Outcome criteria of endo tx?
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
What affects the outcome of the endo tx?
Preop status of periapical tissues
Quality of root canal filling
Quality of coronal restoration
How does the preop status of the periapical tissues impact the outcome of endo tx?
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
How does the quality of the root canal filling impact the outcome?
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
How does the quality of the coronal restoration impact the outcome?
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
How to assess the outcome of the endo tx?
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
How to assess the pt’s symptoms?
Ask about pain, swelling, loss of function
Lack of symptoms does not always mean favourable outcome - clinical and radiographic exam still needed
What may continued pain be due to?
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
What to look at in the clinical exam when reviewing endo tx?
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
How to classify the outcome?
Depends on results of the pts symptoms, clinical outcome and the radiographic examination
- Favourable
- Uncertain
- Unfavourable
Criteria for successful outcome?
Pt is symptom free
Tooth is functional
Radiograph - periapical tissues appear healthy
Criteria for uncertain outcome?
No signs or symptoms
Radiograph - periapical radiolucency stayed the same or gotten smaller within the 4 yr assessment period
Criteria for unfavourable outcome?
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
When to review endo tx depending on the outcome?
Favourable outcome = no further review appts
Uncertain outcome = annular review for up to 4 yrs
Unfavourable outcome = further tx recommended
When to place a definitive restoration?
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
Why does endodontic tx fail?
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
How to recognise post treatment disease?
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
How to manage endo failures?
No tx (monitor)
Extraction
Endo retreatment
Apical surgery
When can a failed endo just be monitored?
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
When to consider extraction?
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
When to do endo treatment?
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%)
What to advise the pt prior to endo retreatment?
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
When should surgical endodontics be carried out?
Indications for surgical endodontics?
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
How to remove GP?
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
How to remove endodontic posts?
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
How to remove thermafil carriers?
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
How to remove silver points?
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
What does the success of removing a fractured instrument depend on?
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
How to remove a fractured instrument?
Achieve good access and vision (microscope)
Ul
How to remove a fractured instrument?
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
What does the prognosis of repairing perforations depend on?
Poor prognosis
Prognosis depends on
- Size of perforation
- Location of perforation
- Condition of remaining tooth
- How infected it is
How to repair perforations?
Repaired internally or externally
MTA or biodentine
Options for managing pts when in practice?
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
