Endodontic Failure Flashcards
When should RCT’s be assessed after treatment has been completed? (according the the European Society for Endodontics).
At least 1 year/6months after treatemtn and subsequently as required
What does the ESE (european society for endodontics) define a successsful RCT as?
- Absence of pain, swelling and other symptoms
- No sinus tract
- No loss of function
- Radiological evidence of a normal PDL
How often does the ESE say RCT’s should be assessed?
At least 1 year (or 6months) after treatment and subsequently as required
What is an uncertain outcome after an endodontic treatment?
An uncertain outcome is if radiographic changes remain the same size or have only diminished in size
If there is an uncertain outcome with a RCT, how often should it be assessed.
It should continue to be assessed until it has resolved (the radiographic changes) for a minimum of 4 years.
If a lesion persists after 4 years then the RCT is considered to be associated with post-treatment disease.
A RCT has an unfavourable outcome when what?
- The tooth is associated with signs and symptoms of infection
- A radiologically visible lesion has appeared subsequent to treatment or a pre-existing lesion has increased in size
- A lesion has remained the same size or has only diminished in size during the 4-year assessment period
- Signs of continuing root resorption are present
What should happen when teeth have an unfavourable outcome?
The tooth needs to undergo further treatment
What is an exception to the rules regarding persisting radiographic changes/pathology?
An extensive radiological lesion may heal but leave a locally visible, irregularly mineralised area (persistence of a radiological lesion).
This defect may be scar tissue formation rather than a sign of persisting apical periodontitis and the tooth should continue to be assessed.
Note:
The tooth should continue to be assessed. Pic shows significant healing but still a radiolucency around the teeth – likely to be scar tissue formation but would need to be checked surgically/histologically.
What is the difference between technical and biological failure?
Technical failure - poor obturation etc. - something wrong with the technique
Biological failure - technique may be good but still have persisting infection
Why do treatments fail? (most common cause)
-technical nature
(not reached a satisfactory standard for the control and elimination of infection)
What 4 factors have been identified as having significance with the failure or success of RCT’s?
- the presense or absence of a lesion post operatively
- the root filling extending within 2mm of the radiographic apex BUT not extruding
- Well condensed root filling with NO voids
- Good quality coronal restoration (want a good coronal seal to prevent coronal leakage)
What influence does the presence or absence of a lesion pre-operatively have?
- There is not much difference between success rates if the tooth is vital or non-vital
- There is a diff in success rates between non-vital with a lesion or without a lesion
- Less success with a lesion present pre-operatively
Why is a good quality coronal restoration important?
If don’t may end up with coronal leakage (a technical failure) which can lead to biological failure.
It is difficult to establish causality of biological failure when there is coronal leakage.
you need a good coronal restoration coupled with good quality RCT.
What additional factors relate to the failure or succes of RCT?
- Presence of a sinus
- Increased lesion size
- No perforation
- Getting patency
- Penultimate rinse with EDTA (reRCT)
- Avoiding missing CHX and NaOCl
- Absence of a flare-up
If you miss a canal when doing a RCT, what have you failed to do?
It is a failed biological objective as leaving infection
How many views of a tooth do you take for RCT? Why?
2 - so that we reduce the risk of missing canals
You need to expect the unexpected when doing RCT’s. What is an example of this?
- Entomolaris and paramolaris where there are additional root canals
What should you bear in mind relating to the canals in upper 6’s?
if there is no second mesial buccal canal, you probably just haven’t found it yet!
What laws are there in order to help improve our hit rate?
- law of centrality
- law of concentricity
- law of CEJ
- Law of symmetry (I and II)
- Law of colour change
- Law of Orification I, II and III
What is the law of centrality?
the floor of the pulp chamber is always located in the centre of the tooth at the level of the CEJ
What is the law of concentricity?
the walls of the pulp chamber are always concentric (share the same centre) to the external surface of the tooth at the level of the CEJ
What is the law of the CEJ?
the CEJ is the most consistent, repeatable landmark for locating the position of the pulp chamber
What is are the Law of Symmetry (I and II)?
Law of Symmetry I – Except for maxillary molars, the orifices of the canals are equidistant from a line drawn in a mesial-distal directions through the pulp-chamber floor.
Law of Symmetry II – Except for maxillary molars, the orifaces fo the canals lie on a line perpendicular to a line drawn in a mesial-distal direction across the centre of the floor of the pulp chamber.
What is the law of colour change?
The colour of the pulp-chamber floor is always darker than the walls.
What are the 3 laws of oriface location?
Law of Orifice Location I – The orifices of the root canals are always located at the junction of the vertical walls and the horizontal floor.
Law of Orifice Location II - The orifices of the root canals are located at the angles in the floor-wall junction
Law of Orifice Location III – The orifices of the root canals are located at the terminus of the root developmental fusion lines
What are some biological reasons for failure?
- Persistent intra-radicular infection
- Extra-radicular bacteria:
- Non-microbial agents
- Cholesterol crystals
- Foreign body reactions
- Scar tissue ‘healing’
Why might there be persistent intra-radicular infection?
- Canal complexities
- Biofilm
- Biofilm diseases are complex microbiological diseases and are very difficult to manage
- Resistant bacteria
- Enterococcus faecalis has been identified as possibly playing a role in failure but is controversial
What non-microbial agents may lead to biological failure?
- Cyst formation – epithelial lined cavity
- Developed from mature granuloma as a result of inflammatory mediators acting on epithelial cell rests
What is the foreign body reaction that may lead to biological failure?
- To GP, paper points etc.
- Results in delayed healing
What are the 2 groups of periapical cysts that you can get?
True cysts (separate from the root canal)
Pocket cysts (continuous with the root canal)
Granulomas, abscesses or cysts are primarilty caused by what and how does this change how they should be treated?
are primarily caused by root canal infections so we should use a treatment protocol that will eliminate their aetiology in the root canal system rather than their product.
The decision on whether or not to retreat a tooth with RCT depends on what?
accurate diagnosis.
The cause of failure needs to be established e.g. technical (perforation, separated instrument), root fracture, other odontogenic pain, non-odontogenic pain (atypical facial pain).
In order to assess the restorative prognosis of a RCT tooth, you need to what?
- Check the presence of fractures
- Assess remaining amount of tooth structure
- Can you get a good seal and will the restoration last?
What are the options for re-treatment?
- Keep under observation
- Orthograde retreatment (normal retreatment)
- Surgical treatment
- Creating a surgical flap and removing the apex of the tooth
- Extraction
In most cases, what re-treatment option offers the best outcome and why?
Non-surgical retreatment (normal RCT retreatment) because most failures are due to inadequate disinfection of the root canal system (there is residual bacteria)
What can make a retreatment more complex? (when would you treat yourself and when would you refer?)
- If the original anatomy has not been damaged the complexity of the treatment is not high
- If there are fractured instruments, blockages, ledges, sever curvatures, it is more complex and so consider referral
- Apical surgery is complex and considered a specialist treatment – consider referral
What would the retreatment plan be for a tooth that has been obturated with insoluble resins?
-use of ultrasonic
What would the retreatment plan be for a tooth that has been obturated with gutta percha?
- handfiles +/- so;vent
- ProTaper D/Reciproc
What would the retreatment plan be for a tooth that has been obturated with soluble pasted?
- handfiles +/- solvent
- ProTaper D/Reciproc
Is it easier to remove well or poorly condensed GP?
Poorly
With well condensed you need to create space within the GP space for files etc
