L22. Endodontic Failure Flashcards
How is the success of endodontics measured (by the ESE)?
- RCT should be assessed at least after 1 year, and subsequently as required (generally 6 months following tx);
- Absence of pain, swelling and other symptoms;
- No sinus tract;
- No loss of function;
- Radiological evidence of a normal PDL.
If radiographic changes stay the same size or has only diminished in size, how long should a post-tx follow up continue?
Up to 4 years
after this time - radiolucency considered as post treatment disease
What signs might suggest RCT has had an unfavourable outcome?
- Tooth is associated with signs and symptoms of infection;
- A radiographic lesion has appeared subsequent to tx 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.
In these situations - further tx required
N.B. Irregular mineralisation of PDL on a radiograph might suggest healing via scar tissue formation
When based on strict criteria (ESE and radiographic) for endodontic outcome, what is the approximate success rate of RCT?
75%
When based on loose criteria (e.g. tooth retained) for endodontic outcome, what is the approximate success rate of RCT?
85%
What is a technical success but biological failure?
- Good obturation via radiograph inc. correct working length, density etc.;
- BUT persistence of periapical radiolucency.
What is a biological success but technical failure?
- Issues with obturation via radiograph e.g. WL cut short, voids etc.;
- BUT resolution of pathology.
What pre-op factors contribute to success?
- Vital v non-vital pulp;
- Periapical lesion v no lesion;
- Tooth type;
- Age;
- Gender.
What operative factors contribute to success?
- Filling within 2mm of radiographic apex;
- Condensation of root filling, with no voids;
- Good quality coronal restoration.
What can happen if filling of a RCT is short?
Indicates inadequate seal/ disinfection
What can happen if a filling of a RCT is long?
- Destroyed/ open apical constriction;
- GP in periradicular tissues;
- GP in maxillary sinus.
What additional factors can contribute to the success of treatment?
- Presence of a sinus;
- Increased lesion size;
- No perforation;
- Getting patency (access to entire canal system);
- Penultimate rinse with EDTA (reRCT);
- Avoiding mixing CHX and NaOCl;
- Absence of flare up.
In what teeth are canals commonly missed?
Upper 6s (usually two MBs)
What is the Law of Symmetry I?
Orifices of the canals are equidistant from a line dram in a medial-distal direction through the pup-chamber floor
(except maxillary molars)
What is the Law of Symmetry II?
Orifices of 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
(except for maxillary molars)
What is the Law of Colour Change?
The colour of the pulp-chamber floor is always darker than the walls
What is the Law of Orifice Location I?
The orifices of root canals are always located at the junction of the walls and the floor
What is the Law of Orifice Location II?
The orifices of root canals are located at the angles in the floor-wall junction
What is the Law of Orifice Location III?
The orifices of root canals are located at the terminus of the root development fusion lines (i.e. dark lines lead us to the orifices in each of the corners)
What biological reasons can cause failure?
- Persistant intraradicular infection;
- Extra-radicular bacteria (made their way out of RC space);
- Canal complexities;
- Biofilm;
- Extruded biofilm;
- Resistant bacteria;
- Enterococcus faecalis (has been seen to be linked to failure);
- Cyst formation (epithelial lined cavity);
- Cholesterol crystals;
- Foreign body reactions causing delayed healing (food/ paper point debris/ GP);
- Scar tissue ‘healing’.
What is a true cyst?
Formation of a cyst, separate to the root canal
What is a pocket cyst?
Formation of a cyst, continuous with the root canal
What is the decision to re-treat, primarily based on?
Cause of failure
What are the options for retreatment that you must discuss with the patient?
- KUO (keep under observation);
- Orthograde retreatment (in most cases failure arises due to inadequate disinfection so this will offer best outcome);
- Surgical treatment;
- Extraction.
What must you consider before retreatment?
Complexity - has this changed from the original anatomy? (e.g. fractured instruments, blockages, ledges, severe curvatures)
