endodontic failure Flashcards
assesment of endo 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
exceptions for success
An 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
pre-op factors affecting success
presence or absence of a lesion
filling extending to within 2 mm of radiographic apex, but not extruded
operative factors contributing to success
well condensed root filling with no voids
good quality coronal restoration
technical complication leading to biological failure
coronal leakage
difficult to establish causality
currently - good coronal restoration coupled with good quality root canal treatment
additional biological factors for success
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
law of symmetry
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 colour change
the colour of the pulp-chamber floor is always darker than the walls
law of orifice
the orifices of the root canals are always located at the junction of the walls and the floor
the orifices of the root canals are located at the angles in the floor-wall junction
the orifices of the root canals are located at the terminus of the root developmental fusion lines
another success factor
achieve and maintain patency
blockages can be due to severe curvature
iatrogenic – avoid the creation of ledges and separation of instrument
biological reasons for failure
Persistant intra-radicular infection:
Canal complexities
Biofilm
Resistant bacteria
Enterococcus faecalis has been identified, but role is controversial
Extra-radicular bacteria:
Actinomycosis
Extruded biofilm
Non-microbial agents:
Cyst formation – epithelial lined cavity
Developed from mature granuloma, inflammatory mediators acting on epithelial cell rests
periapical cysts
split in the literature into true cysts and pocket cysts
prevalence varies in the literature but best evidence is approximately 15%
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
Options for management include:
KUO
Orthograde retreatment
Surgical treatment
Extraction
retreatment
depends on filler material
insoluble resins removal
using ultrasonic
removing old GP points
poorly condensed = hedstroem files
well condensed = need to create space
handfiles and eucalyptus solvent
use proper D1 tip = active Tip - allows better initial penetration into material
pro-taper retreatment
Select lowest speed that effectively engages obturation material 500-700 rpm
Gently press D1 into gutta percha and remove frequently to clean flutes
Continue with D1 until obturation material removed from coronal one-third of canal
Auger obturation material from middle one third of canal with D2
Remove material from apical third with D3, stopping 2-3 mm short of apex
reciproc re-treatment
DO NOT USE SOLVENT
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
unfavourable outcome
The presence of symptoms and loss of function, allied with a likely periapical lucency would be suggestive of an unfavourable outcome.
