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.
