Endodontic Failure Flashcards
How define success? 75%
ESE guidelines
- European society of Endodontology
- RCT should be assessed at least after 1 year and subsequently
- absence of no pain, swelling, other symptoms
- no sinus tract
- no loss of function
- radiological evidence of normal PDL
Unfavourable outcome
- tooth is associated with signs and symptoms of infection
- radiologically visible lesion has appeared subsequent to tx/ pre-existing lesion has increased in size
- lesion has remained same size/ diminished in size during 4 years assessment period
- signs of continuing RR are present
Why do most failures occur?
- tx has not reach a satisfactory standard for control and elimination of infection
Anatomy of pulp-chamber floor
Law of centrality: floor of pulp chamber is always located center of tooth at level of CEJ
Law of concentricity: walls of pulp chamber are always concentric to external surface of tooth at level of CEJ
Law of CEJ: CEJ is the most consistent, repeatable landmark for locating position of pulp chamber
Law of symmetry 1
- except for maxillary molars, the orifices of canals are equidistant from a line drawn in a mesial- distal direction through pulp- chamber floor
Law of symmetry 2
- except for maxillary molars, orifices of canals lie on a line perpendicular to line drawn in mesial- distal direction across centre of floor of pulp chamber
Law of colour change
- colour of pulp chamber floor is always darker than the walls
Law of Orifice 1
- orifices of root canal are always located at junction of walls and floor
Law of orifices 2
- orifices of root canals are located at angles in floor- wall junction
Law of orifices 3
- orifices of root canals are located at terminus of root development fusion lines
Factors contributing to success
- achieve and maintain patency
- blockages can be due to severe curvature
- avoid creation of ledges
- avoid separation of instrument
Causes of failure
- poor planning
- poor access
- poor length control
- forcing instruments
- failure to observe sequence
- failure to maintain patency
Biological reasons for failure
- persistent intra-radicular infection
- canal complexities
- biofilm
- resistant bacteria
- Enterococcus faecalis has been identified
- extra- radicular bacteria, ie: Actinomycosis, extruded biofilm
- non- microbial agents, ie: cyst formation; developed from mature granuloma, inflammatory mediators acting on epithelial cell rests
- cholesterol cyst
- foreign body reactions-> delayed healing
- scar tissue healing
Re-tx Decision making
- is it a technical problem?
- perforation
- separated instrument
- root fracture
- odontogenic pain
- non-odontogenic pain
Assessing restorative prognosis
- check for fractures
- check if you can get proper seal
- is there enough tooth structure left?
- can the restoration last?
Retreatment pathways
Re- tx sequence
ProTaper Re-tx
