Endodontic retreatment involves removing previous root canal fillings and materials to address treatment failure. Success is defined as an asymptomatic tooth with healthy surrounding tissue and bone fill on radiographs. Causes of failure include missed canals, improper length determination, ledges, and perforations. The objectives of retreatment are to regain access, remove all materials, disinfect canals, and obtain proper seal length. Techniques include removing posts, solvents or heat to remove fillings, bypassing ledges or separated instruments, and repairing any perforations. Proper case selection, access, and following technical protocols are important for success.

1. ENDODONTIC RETREATMENT
“ Failure is only the opportunity to begin, again only this time more wis
Henry fo

2. CONTENTS
• Introduction
• Measuring The Success
• Causes Of Failure
• Definition
• Objectives
• Coronal Access Cavity Preparation
• Post Removal
• Regaining Access To The Apical Area
• Removal Of Separated Instruments
• Removal Technique
• Finishing Of Retreatment
• Repair Of Perforation
• Ten Commandments For Improved Success
• Conclusion

3. Success ……
• Asymptomatic
• Periodontium should be healthy
• Radiographs should demonstrate healing or progressive bone fill
overtime.
• Principles of restorative excellence should be satisfied.

4. Causesfor endodonticfailure
GROSSMAN
Poor Diagnosis
Poor Prognosis
Technical difficulties
Careless treatment
Crump
POOR PAST
SELTZER
 Infection
 Mechanical and chemical irritants
 Excessive Hemorrhage
 Broken instruments
 Root perforations
 Unsatisfactory / Incomplete root fillings
 Poor Debridement
 Root fractures
 Periodontal Involvement
 Morphological considerations

5. INTRARADICULAR CAUSES
• Necrotic material remaining in the root canal, either through failure to identify all canals or
treating canals short.
• Contamination of an initially sterile root canal during treatment
• Persistent infection of a root canal after treatment
• Bacteria left in accessory or lateral canals
• Loss of coronal seal and reinfection of a disinfected and sealed canal system

6. EXTRARADICULAR CAUSES
• Persistent periradicular infection
• Radicular cysts
• Vertical root fractures
IATROGENIC CAUSES
• Post perforation

7. DEFINED AS………….
A procedure to remove root canal filling materials from the tooth ,
revise the shape and obturate the canals ; usually accomplished
because the original treatment appears inadequate or has failed or
because the root canal has been contaminated by prolonged exposure
to oral environment.
-A.A. E

8. OBJECTIVES
 To regain access to the apical area of the root canal space in the previously treated
tooth
 Eliminate microorganisms that have either survived previous treatment or have re-
entered the root canal system.
 Remove all necrotic material remaining in the root canal either due to missed main,
accessory , lateral canals.
 Block all the portals of exit or achieve a three dimensional obturation upto the apex
of the tooth.
 Treat any infection persisting after a treatment.
 Regain proper coronal seal and establish proper sealed canals.

10. TREATMENTAPPROACH

11. CORONAL ACCESS CAVITY
Synonym
Quality of coronal seal – assessed preoperatively
REMOVAL OF CROWN
Crown satisfactory - Retaining Adv- Isolation easy
Occlusion is preserved
Esthetics minimally changed
Cost effective
Disadv- Restricted visibility, Anatomy - Iatrogenic mishaps
Removal of canal obstructions - posts
Missing – canals ,hidden recurrent caries, fracture

12. Preserve
1.Access through Crown
Metal- Carbide fissure bur- # 1556
PFM- P- Round diamond copious coolant water spray
M- End cutting bur – Transmetal bur and Great White bur
2. Remove the crown
Chiesel , Flat Plastic and Coupland ‘s Chisel
Ultrasonics
Forceps
K.Y. Pliers- Small replacement Rubber tips and Emery powder
Wynman Crown Gripper , Trail Crown remover and
Trident Crown Placer/ remover

13. Roydent Bridge Remover -
Easy Pneumatic Crown and Bridge Remover, Coronaflex- create impact with
compressed air will remove it
Morell Remover - force manually using a sliding weighed handle
• Metalift , Kline Crown Remover and Higa Bridge Remover - Conservative
approach
• Richwil Crown & Bridge remover-

14. POST REMOVAL
Depends upon
• Type, Shape ,Design of the post
• Location of tooth
• Materials used to cement the post
• Techinques
“It is not only what is removed but also what is left behind that is important”.
First step-- Expose it properly
Bulk of core material-- High speed hand piece - Cylindrical or tapered
carbide or diamond burs
Last embedding core material – Less aggressive – Tapered , mid sized ultrasonic tip
Minimal restorative material remaining – Small sized ultrasonic instrument

15. Once well isolated and freed from all restorative material-
 Retention of Post should be reduced
 Medium sized US tips - AT THE INTERFACE
 Care to be taken not push with too much force
 If root is thin , smaller US tips are used –DRY - limit visibilty & accumulation of
debris
 If rubber dam , Post flooded with Solvents like Chloroform and later
activated
 Roto- Pro Bur – 3 shapes , Six sided , non cutting tapered burs in high speed
hand piece - decreases the retention

16. POST REMOVAL KITS
Gonon Post Removing System- Parallel or Tapered
Non active Preformed
Hollow Trephine bur
Specific extraction mandrel – create or tap a thread on to exposed milled
portion of post – Extraction forceps or vise is applied to tooth and post – Turning
the screw on the handle of the vise will create a coronal force
Drawbacks – Size of vise – makes the access diff- molars, crowded Mand incis.
Thomas Screw Post Removal Kit - Active or Screw post
Extraction mandrel are threaded in opposite direction

17. Ruddle Post Removal System – Combines the properties
JS Post Extractor – Advan – Smaller size- inaccessible areas
PULLING ACTION
Disadvantage- Large variety of trephine burs or
extraction mandrel
Post Puller or Eggler Post Remover – No trephine burs or extraction mandrels
2 sets of jaws – independent
High speed handpiece & bur tooth and post
Not recommended for Screw post

18. TOOTHCOLOUREDPOSTS
Ceramic , Zirconium, Various Type Of Fiber Reinforced Composite
LARGO BUR , PAESO DRILL
REMOVAL BURS IN THE KIT
Gyro tip- flutes, Plasma coated silicon carbide
POTENTIALCOMPLICATIONS OF POST REMOVAL
Fracture of tooth
Leaving the tooth non restorable
Root perforation
Inability to remove the post
Heat generated - ultrasonics

19. REGAINING ACCESS TO APICAL AREA

20. PASTES
N2 OR RC 2B- Formaldehyde , Heavy Metal Oxides
CAN BE
A. SOFT PASTES- Easy
Crown Down Instr . With copious Irrigation
B.HARD PASTES – Probed with endo explorer or file
BUR OR US tip in easily accessible
straight portions
Curvature- precurved , small files are inserted
Densely filled – solvents

21. Ultrasonics – Hard paste in curved apical area
Energy will break up the paste
Biocalex 6.9- EDTA CAN BE USED

22. GUTTA PERCHA REMOVAL
• Relative ease of removal
• Combination of Heat, Solvent and Mechanical Instrumentation
Initial probing - Rule out - possibility of solid core
If present – no heat
Not present- Endodontic heat carrier – cherry red glow
Other heat sources – Touch ’N Heat
Remaining Coronal material – Small GG DRILLS
Canal probed using 10 – 15 no file can remove or bypass the
existing cones
Densely filled- Solvent

23. SOLVENTS
 Chloroform
 Methyl chloroform
 Xylene
 Eucalyptol
 Halothane
 Rectified turpentine
Most popular
Dissolves rapidly
Long history –
clinical use
Carcinogenic
Less toxic
Less Effective
Dissolve slowly
Effective when
heated
Volatile
Potential for idiosyncratic
hepatic necrosis
Pungent Odour
High level of Toxicity

24. TECHNIQUE
Solvent introduced into coronal portions acts as reservior
Small files are used to penetrate the remaining root filling and SA
Precurved rigid files such as C+ files- more efficient
Radiograph – taken when estimated length is approached- avoid Overextending
Once WL reached – Progressive Larger diameter hand files - rotated in Passive, non binding
clockwise reaming motion – Remove bulk of GP
Frequent replenishment of solvent
When last loose fitting instrument – removed clean- solvent acts as Irrigant.
Solvent removed with paper points
Use kinked small files, probe the canal wall for irregularities

25. Glass ionomer assealer
• Insoluble In halothene and chloroform
• Done by removing GP – US to debride canal walls
OVEREXTENDINGFILLING
• H file -- extruded apical fragment of root filling – clockwise
rotation – withdrawn without rotation
• Should not be softened with Solvent

26. ROTARY SYSTEMS
Enhanced efficiency and effectiveness in removing
Risk of instrument separation
LASERS
Nd YAG – time is same
considerable amount was left
Root surface temperature increased
RESILON- Cone – Heat
Solvent- Endosolv -R

27. SOLID CORE OBTURATORS
More complex & difficult
Method depends upon-
Type- Plastic - smooth sided
Metal - fluted
Level at which carrier is cut- 2-3 mm above the pulp chamber
For post space prepa – nicked at the middle and inserted apically

28. TREATMENT STEPS
PREOPERATIVE RADIOGRAPH
CAREFUL ACCESS AND PROBING- metallic structure embedded in the GP mass
Black spot
Metallic carrier- Heat applied– soften GP- REMOVED – Peet silver point forceps or modified
Steiglitz forceps
If not enough space available--- Solvent application – using small hand instruments – followed by
ultrasonic activation-- removing it
Plastic Carrier – Heat should be avoided
Older – VECTRA- Insoluble in solvents
POLYSULFONE- soluble in Chloroform
Newer carriers not soluble

29. STEPS-
Access flooded –GP removed – Larger to smaller hand files
Solvent – replenished- 8 no. file - extend to apical area
When little GP remaining – large H File – inserted alongside plastic carrier –
gently turned clockwise to engage the flutes- pulled
Care to be taken not to overstress the instrument
Recently- System B Heat source- soften GP
AT 225 0 c
Rotary Instruments
Difficult to remove sealer and GP – alpha phase
Solvent –wicking with paper point

30. SILVERPOINTS
• Minimal Taper and smooth sided
Removal technique
Establish proper access
Coronal portion embedded in Core material – Carefully removed
with bur and US
Flood the access- for cement dissolution
Endo. Explorer and Small file carries solvent down the silver pt
Replenish the solvent
Grasp the exposed end with – Stieglitz pliers or some other
forceps
Gently pull it out

31. If no good purchase – cone held with forceps - that is held with hemostat or needle
driver - allow removal
If held in tight friction grip- Indirect US - can be used to loosen it
If not much exposure – Caufield silver point retrievers can be used
Spoon with groove in the tip
Available in three sizes – 25, 35 and 50.
Other techniques
1. H FILES- Requires some space in the coronal area
Sealer is dissolved

32. • If more exposure is required , Use of trephine bur and microtubes or
ultrasonics
• SEVERAL EXTRACTION DEVICES –
• Masserann kit
• Endoextractor
• Separated Instrument Retrieval System etc
• Once removed instrumentation – Crown down- prevent extrusion of
Corrosion Products

33. BROKEN INSTRUMENT
Types of Instrument
Can be seen during diagnosis
After removal of GP
Causes
“Stressed” instrument
Placing exaggerated bends
Forcing a file before canal opened
sufficiently + reaming motion.
Inadequate access
Anatomy
Manufacturing defects
The best antidote for a broken file is PREVENTION.

34. PROGNOSIS
Depends on
What stage
Preoperative Status
Whether file can be removed or bypassed
Removal depends on
Location
Root curvatures, External root concavities , Root thickness
Type of material – NiTi and Stainless Steel

35. RemovalTechniques
Headlamp and Magnifying loupes
Operative Microscope
Treatment Approach
Visible in Coronal Access – Grasp – Hemostat or Steiglitz Forceps
Technique- ACW
Deep – Visibility difficult
Create straight line Coronal – radicular access
Modified GG DRILLS – Create circumferential staging
platform
US tip – placed bet exposed file & wall and is vibrated around the
obstruction in CCW – Causes Unscrewing forces
Occasionally , file will jump out

36. Other methods
1. Microtube technique- SS TUBING
Small H file inserted
2.Wire Loop And Tube Method-25 Gauge injection needle
with 0.14 mm diameter steel ligature
3.ENDODONTIC EXTRACTOR KIT- 4 sizes of Trephine burs and extractors ,
Cyanoacrylate adhesive – Bonds hollow tube -exposed file
Imp factor- Snughly fit
Recommended overlap – 2mm
Disad- 1.Smaller separate instrum should be used
2. Very aggressive

37. • Masserann kit – Trephine burs + Extraction device
Cut in CCW Internal Stylus WEDGE The
file against the internal wall of mandrel
Disadv- Removes excess of tooth structure

38. • Extraction System From Roydent
1 Bur 3 Extraction Devices
Very conservative Small
Removes minimal amount of tooth Remove Smaller obstructions
Surround obstruction with six prongs
DISADV- Lack of variety of Instr
Possibility of separating obstruction with bur
Potential problem of breakage

39. Cancellierinstrument
Extractors + Handle + Adhesive
No trephine
• MounceExtractor
Ball burnisher with slots + Cyanoacrylate

40. • InstrumentRemoval System (I.R.S.)
Microtube & Screw wedge
• Separated InsrumentRetrieval(S.I.R.)- Extractor tube bonded to
obstr

41. MANAGEMENT OF CANAL IMPEDIMENTS

42. LEDGE
• An artificially created irregularity on the surface of
the root canal wall that prevents the placement of
instruments to the apex of an otherwise patent canal.
MANAGEMENT
• Locate the ledge
• Irrigate
• No. 10 or 15- distinct curve at the tip (1 to 3 mm)
• Pointed toward the wall opposite the ledge.
• “Tear-shaped” silicone instrument stops

43. • Vaivén/watch-winding /stem-winding/twiddling
• Resistance - retract slightly, rotate, and advance again
• Until it bypasses; teased apically
• Radiograph
• Do not remove - circumferential filing
• Subsequent files used in the same manner to
maintain the true pathway
• Greater taper files can also used to reduce the
extent of the ledge while using minimum number
of files.

44. FINISHINGTHE RETREATMENT

45. REPAIROF PERFORATION
CAUSE OF Post Endodontic Disease
Causes- Pathologic- Resorption, Caries
Iatrogenic – During Root Canal Therapy,aftermath
Found – Diagnosis
Angled Radiographs
Periodontal Assessment – Cervical
Corrected – 2 Options
Non Surgical Method – Preferred
Less invasive
Better isolation

46. • Prognosisdependson-
• Location- More coronal better
• Time elapsed - immediate better
• Previous contamination with Microbes
• Ability to seal the defect – Commonly used material- Amalgam, Super EBA
cements, bonded composite material
• Recently MTA-Seals well even in presence of Blood
Cementum like material has been shown to grow

47. STEPS
CORONAL THIRD
Access obtained
Canals instrumented
Defect cleaned and enlarged – Infected dentin
Bleeding
Haemostats- collagen, CaSO4, CaOH
COVER The orifices of canal
EXAMINE THE SITE
No osseous defect Osseous defect
support by ext matrix- HA
Place repair material
SEAL THE TOOTH

48. MIDDLE THIRD
Surgical operating microscope
ALL STEPS ARE SIMILAR
Canal protected – file
Place MTA – US energy on the file
MTA slumps into defect
File – should be 1-2 mm push pull-
Easily remove
APICAL THIRD
Associ- ledge or block
Obturation of apical area MTA / GP
Outcome unpredictable

49. Prognosis of Retreatment
• Proper diagnosis and all technical aspects
• Largely depends on apical periodontitis proir to
treatment

50. TEN COMMANDMENTS
1. Use great care in case selection
2.Use greater care in treatment
3.Establish adequate cavity preparation
4.Determine the exact length of tooth to the foramen
5.Always use curved, sharp instruments in curved canals
6.Use great care in fitting the primary filling point
7.Use periradicular surgery only in those cases for which surgery is definitely indicated.
8.Always check the apical density of the completed root canal filling
9.Properly restore each treated pulpless tooth to prevent coronal fracture and
microleakage
10.Practice endodontic techniques

51. CONCLUSION

52. THANK YOU