Endo failure Flashcards
assessment of RCT outcome
- Root canal treatment should be assessed at least after 1 year and subsequently as required
- Absence of pain, swelling and other symptoms
- No sinus tract
- No loss of function
- Radiological evidence of a normal PDL
uncertain outcome
if radiographic changes remain the same size or has only diminished in size. In this situation it is advised to assess the lesion further until it has resolved or for a minimum period of 4 years. If a lesion persists after 4 years the root canal treatment is usually considered to be associated with post-treatment disease.
RCT has unfavourable outcome when (4)
- 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
In these situations it is advised that the tooth requires further treatment.
exceptions to RCT failure
extensive radiological lesion may heal but leave a locally visible, irregularly mineralized area. This defect may be scar tissue formation rather than a sign of persisting apical periodontitis. The tooth should continue to be assessed
ESE guidelines for endo success
strict radiographic criteria
technical Vs Biological outcome of success
it’s not just about the white line radiolucency around the apex
why do RCTs fail
“Most failures occur when treatment procedures, mostly of a technical nature, have not reached a satisfactory standard for the control and elimination of infection”
4 factors that are significant in RCT failure
pre-op factors affecting success
- presence or absence of a lesion
- operative factors contributing to success
- filling extruding to within 2mm of radiographic apex but not extruded
- well condensed root filling with no voids
- good quality coronal restoration
3 technical complications leading to biological failure
- Coronal leakage
- Difficult to establish causality
- Currently - good coronal restoration coupled with good quality root canal treatment
additional factors that can contribute to failure (7)
- Presence of a sinus
- Increased lesion size
- No perforation
- Getting patency
- Penultimate rinse with EDTA (reRCT)
- Avoiding mixing CHX and NaOCl
- Absence of a flare up
what can cause failure in biological objective
missed canals
- no MB2, probably just not found it yet
improve hit rate by
know anatomy of pulp chamber and floor
centrality and concentricity
law of symmetry I
Except for maxillary molars, the orifices of the canals are equidistant from a line drawn in a mesial-distal direction through the pulp-chamber floor
law of centrality
the floor of the pulp chamber is always located in the centre of the tooth at the level of the CEJ
law of concentricity
the walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the CEJ
low of the CEJ
the CEJ is the most consistent, repeatable land mark for locating the position of the pulp chamber
law of symmetry II
except for the maxillary molars, the 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
law of colour change
the colour of the pulp-chamber floor is always darker than the wall
law of orifice location I
the orifices of the root canals are always located at the junction of the walls and the 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
2 factors which contribute to success
- Achieve and maintain patency
- Blockages can be due to severe curvature
2 types iatrogenic damage contributing to RCT failure
avoid creation of ledges
avoid separation of instrument
6 factors to avoid creation of ledges
- Poor planning
- Poor access
- Poor length control
- Forcing instruments
- Failure to observe sequence
- Failure to maintain patency
how can instrument separation lead to failure
infect RCS
6 biological reasons for failure
- Persistent intra-radicular infection
- Extra-radicular bacteria
- Non-microbial agents
- Cholesterol crystals
- Foreign body reactions – delayed healing (food debris etc)
- Scar tissue ‘healing’
how can persistent intra-radicular infection lead to failure (4)
- Canal complexities
- Biofilm
- Resistant bacteria
- Enterococcus faecalis has been identified, but role is controversial
how can extra-radicular bacteria lead to failure (2)
- Actinomycosis
- Extruded biofilm
how can non-microbiological agents lead to failure (2)
- Cyst formation – epithelial lined cavity
- Developed from mature granuloma, inflammatory mediators acting on epithelial cell rests
true cyst
separate from RCS
pocket cyst
continuous with RCS
periapical cysts
Split in the literature into true cysts (separate from RCS) and pocket cysts (continuous with RCS)
Prevalence varies in the literature but best evidence is approximately 15%
how to treat cysts
therapy resistance without surgery
Granulomas, abscesses, or cysts, are primarily caused by root canal infection, we should use a treatment protocol that will eliminate their aetiology in the root canal system rather than their product
retreatment decision making
Decision making process depends on an accurate diagnosis
Establish the cause of the failure
- Technical e.g. perforation, separated instrument
- Root fracture
- Other odontogenic pain
- Non-odontogenic pain e.g. atypical facial pain
4 possible causes of failure
- Technical e.g. perforation, separated instrument
- Root fracture
- Other odontogenic pain
- Non-odontogenic pain e.g. atypical facial pain
assessing restorative prognosis (3)
- Check for the presence of fractures – need good magnification and illumination
- Assess remaining amount of tooth structure
- Can you get a good seal and will the restoration last?
retreatment planning
Options for management include:
- KUO
- Orthograde retreatment
- Surgical treatment
- Extraction
Already seen that most failures due to inadequate disinfection of the root canal system initially, leaving residual bacteria
In most cases therefore, non-surgical retreatment will offer best outcome
complexity considerations
If the original anatomy has not been damaged the complexity of the treatment is not high
If there are fractured instruments, blockages, ledges, severe curvatures, it is more complex and so consider referral
Apical surgery is complex and considered a specialist treatment – consider referral
endodontic failure management retreatment for insoluble resins
ultrasonics
endodontic failure management retreatment for GP
handfiles +/- solvent
ProTaper D/Reciproc
endodontic failure management retreatment for soluble pastes
handfiles +/- solvents
ProTaper D/ Reciproc
removing GP if poorly condensed
generally easier
Hedstoem files
removing GP if well condensed
generally harder
need to create space
Handfiles +/- solvent
ProTaper retreatment
ProTaper D1 Active Tip - allows better initial penetration into material Beware - Curved canal – perforation likely
ProTaper Retreatment sequence
D1 for coronal filling removal
D2 for middle filling removal
D3 for apical filling removal
retreatment sequence
- select lowest speed that effectively engages obturation material (500-700rpm)
- gently press D1 into GP and remove frequently to clean flutes
- continue with D1 until obturation materials removed from coronal third of canal
- auger obturation material from middle third of canal with D2
- remove materials from apical third with D3, stopping 2-3mm short of apex
- by pass ledges with pre-curved C+ files
- check patency and determine working length
the RECIPROC system
Size and dimensions of instruments
- Very efficient
- Remove bulk of gutta-percha (US, heat carrier)
- Use solvent (chloroform, eucalyptus oil)
- Use R25 as described
- Increased apical enlargement (R40, R50)
- Brushing with Reciproc
Heat GP using thermal plugger, R25 in pecking motion, take out filling material used in old preparation
Avoid using solvent as leave a smear on surface – can soften if feel able to get into RCS
solvent used in retreatment
Avoid using solvent as leave a smear on surface – can soften if feel able to get into RCS
