retreatment in endo

retreatment

1. ENDODONTIC RETREATMENT “ Failure is only the opportunity to begin, again only this time more wisely” Henry ford

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. Causes for endodontic failure 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.

9. TREATMENT APPROACH

10. 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

11. 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

12. 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-

13. 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

14. 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

15. 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

16. 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

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

18. REGAINING ACCESS TO APICAL AREA

19. PASTES N2 OR RC 2B- Formaldehyde , Heavy Metal Oxides CAN BE 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

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

21. 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

22. 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

23. 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

24. Glass ionomer as sealer Insoluble In halothene and chloroform Done by removing GP – US to debride canal walls OVER EXTENDING FILLING H file -- extruded apical fragment of root filling – clockwise rotation – withdrawn without rotation Should not be softened with Solvent

25. 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

26. 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

27. 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

28. 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 c Rotary Instruments Difficult to remove sealer and GP – alpha phase Solvent –wicking with paper point

29. SILVER POINTS 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

30. 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 H FILES - Requires some space in the coronal area Sealer is dissolved

31. 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

32. 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 .

33. 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

34. Removal Techniques 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

35. 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

36. 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

37. 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

38. Cancellier instrument Extractors + Handle + Adhesive No trephine Mounce Extractor Ball burnisher with slots + Cyanoacrylate

39. Instrument Removal System (I.R.S.) Microtube & Screw wedge Separated Insrument Retrieval (S.I.R. )- Extractor tube bonded to obstr

40. MANAGEMENT OF CANAL IMPEDIMENTS

41. 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

42. 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.

43. FINISHING THE RETREATMENT

44. REPAIR OF 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

45. Prognosis depends on- 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

46. 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

47. 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

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

49. 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

50. CONCLUSION

51. THANK YOU