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Presented by : Dr. Arpit Viradiya
Guided by : Dr. Ashutosh Paliwal
Introduction
• Since long, many studies are being conducted
to determine success and failure of
endodontic treatments.
• D...
• The usual goal of endodontic therapy is to
prevent or heal the disease.
• Accordingly, endodontic treatment outcomes
sho...
Definitions related to endodontic
treatment outcome
• Healed : In which both clinical and
radiographic presentations are n...
• A clear definition of what constitute a failure
following endodontic therapy is not yet clear.
• Failures cannot be subs...
Clinical criteria of success of
endodontic treatment
• No tenderness on percussion/palpation.
• Normal tooth mobility.
• N...
Radiographic evaluation
• The radiographic criteria for failures are
development of radiographic periapical areas
of raref...
Histological criteria of success of
endodontic treatment
• Absence of inflammation.
• Regeneration of PDL fibers.
• Presen...
Factors affecting success or failure
• Diagnosis and treatment planning.
• Radiographic interpretation.
• Anatomy of tooth...
Infection
• Presence of infected and necrotic pulp tissue
in root canal acts as the main irritant to the
periapical tissue...
Incomplete debridement of the root
canal system.
• It is a principle factor contributing to
endodontic failures.
• The mai...
• The poor debridement can lead to residual
microorganisms, their byproducts and tissue
debris which further recolonize an...
Excessive hemorrhage
• Small haemorrhages during endodontic
procedure are repaired without incident.
• Extirpation of pulp...
• Mild inflammation is produced because of
local accumulation of blood.
• The extravasated blood cells and fluids must
be ...
Overinstrumentation
• Instrumentation beyond
apical foramen causes
decrease in the prognosis of
endodontic treatment
becau...
• When instrumentation of the root canal
system remains within the confines of root
canals, the chances of success of endo...
Chemical irritants
• During endodontic
treatment, various
medications are used as
dressing in root canal.
• Their function...
• They decrease the prognosis of endodontic
therapy if get extruded in the periapical
tissues.
Int J Periodont Restorative...
Instrument separation
• Schilder et al reported that
– If instrument separation occurred in tooth with
presence of vital p...
• Basically separated instruments impair the
mechanical instrumentation of infected root
canals apical to instrument, whic...
Canal blockage and ledge formation
• Canal blockage can occur due to accumulation
of dentin chips or tissue debris which p...
• Ledge formation usually occurs
by using straight instruments in
curved canals.
• All these lead to working short
of the ...
Perforations
• It is a mechanical communication between
root canal system and the periodontium.
• It occurs by
– Lack of k...
• Location : Depends on its closeness to gingival
sulcus.
• Time : which has elapsed before defect is
repaired
• Adequacy ...
Incompletely filled teeth
• It occurs due to
– Incomplete instrumentation
– Ledge formation
– Blockage
– Improper measurem...
• Remaining infected necrotic tissue,
microorganism and their byproducts in
inadequately instrumented and filled teeth
cau...
Overfilling of root canals
• It occurs because of
– Apical root resorption
– Incompletely formed roots (open
apex)
– Over ...
• The filling material acts as a foreign body
which may generate immunological response.
• Several studies have shown biof...
Corrosion of root canal fillings
• Corrosion is the
tendency of most of the
metals to revert to their
lower form by oxidat...
• The main area of corrosion of silver cones is
coronal and the apical portions, the areas
which contact tissue fluids via...
Anatomic factors
• Presence of overly curved
canals, calcifications, numerous
lateral and accessory canals,
bifurcations, ...
Root fractures
• Endodontic failures can occur by partial or
complete fractures of the roots.
• Prognosis of teeth with ve...
Traumatic occlusion
• Traumatic occlusion has also been reported to
cause endodontic failures because of its effect
on per...
Periodontal consideration
• An endodontic failure may occur because of
communication between the periodontal
ligament and ...
• Also the recession of attachment apparatus
may cause exposure of lateral canals to the
oral fluids which can lead to rei...
Systemic factors
• The systemic disease may
influence the local tissue
resistance and thus interfering
with the normal hea...
• Thus severe reaction may occur following
cleaning and shaping.
• Healing is also impaired in patients with
systemic dise...
• Various systemic factors can interfere with
success of endodontic therapy are
– Nutritional factors
– Diabetes mellitus
...
Before going for endodontic
retreatment following factors should
be considered
• If patient is asymptomatic even if treatm...
Before performing retreatment
following points should be considered
• Retreatment may be performed to prevent the
potentia...
• Root canal filling materials have to be
removed during retreatment.
• Prognosis of retreatment could be poorer than
the ...
• Definition : Endodontic retreatment is a
procedure performed on a tooth that has
received prior attempted definitive tre...
Steps in retreatment technique
• Access to root canal
– Through crown
– By removal or crown
• Access to apical area
– By r...
CORONAL DISASSEMBLY
• Clinicians generally access the pulp chamber
through the existing restoration if it is
functionally ...
Factors influencing restoration
removal
• PREPARATION TYPE
• RESTORATION DESIGN & STRENGTH
• RESTORATIVE MATERIAL
• CEMENT...
There are several important removal
devices which may be divided into
three categories:
1. Grasping instruments : K.Y. Pli...
• Percussive instruments : Crown-a-Matic and
the Coronaflex
Coronaflex
• Passive-active instruments : Metalift and the
Higa Bridge Remover.
Metalift
• Clinicians must clearly define the risk versus
benefit with patients before removal of an
existing restoration.
• Gaining access through existing restoration
helps in :
– Facilitating rubber dam placement
– Maintaining form, function ...
Establish access to root canal system
• In some cases post and core needs to be
removed for gaining access to the root can...
TECHNIQUES FOR POST REMOVAL:
• Successful post removal requires removing all
circumferential restorative material from pul...
ULTRASONIC METHOD:
• Piezo electric ultrasonic systems offers the
clinician certain advantages in endodontic
disassembly a...
• CPR - 3,4, & 5 instruments are
designed to work in small, restricted
and confined spaces.
• If space is severely restric...
• Once the post has been fully exposed,
rotosonics can be used to loosen and
remove the post.
• The regular ROTOTIP (Ell m...
• CPR-1 has a ball at its working end which is
kept in contact with post to maximize energy
transfer.
• This is used with ...
Removing canal obstructions and
establishing patency
• Patency of canal can be regained by removing
obstructions in the ca...
Silver point removal
• Silver points can be retrieved from
canal by following methods:
– Using microsurgical forceps – Its...
• Using hedstroem files : In this headstroem
files are placed in the canal.
• These files are twisted around each other by...
• Using hypodermic needle which
is made to fit tightly over the
silver point over which
cyanoacrylate is placed as an
adhe...
Gutta-percha removal
• The relative difficulty in removing GP varies
according to the
– Canal length
– Canal c/s dimension...
• Dividing the root into three parts G.P. is
initially removed from canal in coronal 1/3,
then middle 1/3 & finally elimin...
• Single cone:
• They can be removed by using
– A headstroem file
– Tweezers
– Steiglitz forceps
– Endosonics.
• H file method : largest H-files that will fit the
cone should be used to reduce the risk of
fracture.
• The file is gent...
• Endosonics can also be used.
• It loosen the cement around the single cone,
there by aiding removal.
• If cones are acce...
• CONDENSED GUTTA PERCHA
• Condensed G.P. can be removed using a
combination of
– Heat
– G.G drills
– Niti rotary instrume...
Heat
• Traditionally power source in conjunction with
specific heat carrier instrument such as Touch
- N - Heat / system B...
• Disadvantage: It limits its ability to place into
under-prepared systems and around pathways
of curvature.
• Technique: ...
• The heat carrier is
then deactivated.
• And as it cools,
withdrawal will result
in removal of attached
fragment of G.P.
...
Heat & Instrument removal
• In this method a hot instrument is placed into
G.P. & immediately with drawn to heat soften
th...
• When GP cools, it will freeze on flutes of file.
• In poorly obturated canals, removing the file
can, at times, eliminat...
Solvents:
• Solvents include chloroform, xylene,
rectified turpentine, chloroform &
eucalyptus oil.
• There has been some ...
• Solvents should be used only in small amounts
and must be contained with in R.C. system.
• Using solvent too early in tr...
FILE & CHEMICAL REMOVAL
• It is the best option to remove G.P from small
& curved canals.
• The technique involves filling...
• Frequent irrigation creates a pilot hole and
sufficient space for the serial use of larger file
to remove G.P.
• This me...
Paper point & chemical removal
• G.P. & most sealers are miscible in chloroform
& once in solution can be absorbed and
rem...
• In this technique, the canal is
1st flushed with chloroform &
solution is then absorbed &
removed with appropriately
siz...
• Process is repeated as long as it continues to
be visibly productive.
• After chloroform wicking procedures, canal is
fl...
Rotary Removal
• Active Niti rotary files (dentsply) are the most
effective & efficient instruments for G.P.
removal.
• Di...
• When attempting for removal, the R.C. should
be divided to 3 parts.
• Select appropriately sized rotary instrument
that ...
ULTRASONIC
• Piezoelectric ultrasonic system represents a
useful technique to rapidly remove G.P.
• Ultrasonic instrument ...
• Specially designed ultrasonic instrument are
carried into canals, that have sufficient shape
to receive them.
• This met...
G.G.Drills / Burs:
• G.G. drills are extremely efficient for removing
G.P. from coronal parts of well compacted root
canal...
Carrier Based Gutta Percha Removal
• Techniques are same as for G.P & silver point.
• Initially it used to be metal & file...
• Carrier is grasped with the pliers and removal is
attempted using fulcrum mechanics rather than
a straight pull out of t...
Paste removal
• When evaluating a paste case for retreatment,
it is useful to chemically understand that
pastes can genera...
• However, it is important to understand that
because of the method of placement, the
coronal portion of paste in the cana...
Broken Instrument Removal
• During R.C. preparation procedures, the
potential for instrument breakage is
always present.
•...
• Historically, the consequences of leaving / by
passing broken instruments have been
discussed and varieties of approache...
Factors influencing broken instrument
removal
• Cross sectional diameter, length & curvature of
R.C.
– If 1/3 of overall l...
• Type of material comprising the obstruction
– S.S. files - easier to remove as they do not #
during removal process.
– N...
Steps
• 1st step  Coronal access 
• High speed friction grip surgical length burs
are selected to create straight line a...
• These G.G drills are then used like “brushes”
to create additional space and maximize
visibility coronal to obstruction....
Staging Platform
– This is done by selecting a G.G. with maximum c/s
diameter that is slightly larger than the visualized
...
• This clinical action creates a small
“Staging Platform” that facilitates the
insertion of zirconium nitride coated
ultra...
• So, to prevent this it is wise to place cotton
into the other orifice.
• Once the ultrasonic instrument is selected,
bas...
• Then the selected tip is moved
lightly in counter clockwise direction
around the obstruction and
trephines around the co...
Apical Obstructions / Blockage
• When canals have been under filled,
obstructive calcification might be found apical
to un...
• At this stage if possible the intracanal anatomy
should be inspected carefully under
microscope.
• Then a small size pre...
Ledges:
• Often a ledge has been formed at the end of
the previous obturation of the canal.
• Most of the time ledge is th...
• Flood the canal with irrigating solution.
• Select a no. 10 S.S. K file place a sharp 1mm
curvature at the tip and orien...
• Pick gently with very short strokes, searching
for a catch.
• This procedure will remove the irrigant and
help to disint...
• When the file moves freely, it may be turned
clockwise on withdrawal to smoothen or
eliminate the ledge.
Conclusion
• Training proctol and technology allow
clinicians to greatly expand their abilities in
non surgical retreatmen...
References
Endodontic faiures
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Endodontic faiures

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About failures of root canal treatment and retreatment. This presentation describes about various techniques for gutta percha removal, posts removal, pastes removal, and removal of separated instrument

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Endodontic faiures

  1. 1. Presented by : Dr. Arpit Viradiya Guided by : Dr. Ashutosh Paliwal
  2. 2. Introduction • Since long, many studies are being conducted to determine success and failure of endodontic treatments. • Different studies have shown that the success rate for a root canal treatment ranges from 54 to 95 percent. • Success is defined by goals established to be achieved.
  3. 3. • The usual goal of endodontic therapy is to prevent or heal the disease. • Accordingly, endodontic treatment outcomes should be defined in reference to healing and disease.
  4. 4. Definitions related to endodontic treatment outcome • Healed : In which both clinical and radiographic presentations are normal. • Healing : It is a dynamic process, reduced radiolucency combined with normal clinical presentation. • Disease : Means no change or increase in radiolucency, clinical signs may or may not be present or vice versa.
  5. 5. • A clear definition of what constitute a failure following endodontic therapy is not yet clear. • Failures cannot be subscribed to any particular criteria of evaluation. • Instead success or failures after endodontic therapy could be evaluated from combination of various criteria like clinical, histopathological and radiographical criteria.
  6. 6. Clinical criteria of success of endodontic treatment • No tenderness on percussion/palpation. • Normal tooth mobility. • No evidence of subjective discomfort. • No sign of infection/swelling. • No sinus tract or integrated periodontal disease. • Tooth having normal form, function and esthetics.
  7. 7. Radiographic evaluation • The radiographic criteria for failures are development of radiographic periapical areas of rarefaction after endodontic treatment, in cases where they were not present before the treatment. • Or increase in size of radiolucency after endodontic treatment.
  8. 8. Histological criteria of success of endodontic treatment • Absence of inflammation. • Regeneration of PDL fibers. • Presence of osseous repair. • Repair of cementum. • Repair of previously resorbed areas. • Absence of resorption.
  9. 9. Factors affecting success or failure • Diagnosis and treatment planning. • Radiographic interpretation. • Anatomy of tooth and root canal system. • Debridement of the root canal space. • Asepsis of treatment regimen. • Quality and extent of apical seal. • Systemic health of the patient. • Skill of the operator.
  10. 10. Infection • Presence of infected and necrotic pulp tissue in root canal acts as the main irritant to the periapical tissues. • For success of endodontic therapy, thorough cleaning of root canal system is required for removal of these irritants.
  11. 11. Incomplete debridement of the root canal system. • It is a principle factor contributing to endodontic failures. • The main objective of root canal therapy is the complete elimination of the microorganisms and their byproducts from the root canal system.
  12. 12. • The poor debridement can lead to residual microorganisms, their byproducts and tissue debris which further recolonize and contribute to endodontic failure.
  13. 13. Excessive hemorrhage • Small haemorrhages during endodontic procedure are repaired without incident. • Extirpation of pulp and instrumentation beyond periapical tissues lead to excessive hemorrhage.
  14. 14. • Mild inflammation is produced because of local accumulation of blood. • The extravasated blood cells and fluids must be resorbed otherwise they act as foreign body. • Also the extravasated blood acts as nidus for bacterial growth especially in presence of infection.
  15. 15. Overinstrumentation • Instrumentation beyond apical foramen causes decrease in the prognosis of endodontic treatment because of trauma to periodontal ligament and alveolar bone.
  16. 16. • When instrumentation of the root canal system remains within the confines of root canals, the chances of success of endodontic therapy are more. (Strindberg et al 1956)
  17. 17. Chemical irritants • During endodontic treatment, various medications are used as dressing in root canal. • Their functions are to eliminate or reduce microbial flora, prevent or lessen pain, reduce inflammation or stimulate repair.
  18. 18. • They decrease the prognosis of endodontic therapy if get extruded in the periapical tissues. Int J Periodont Restorative Dent 17:75, 1997
  19. 19. Instrument separation • Schilder et al reported that – If instrument separation occurred in tooth with presence of vital pulp before treatment, prognosis was not much affected. – but if instrument separation occurred in teeth with pulpal necrosis, prognosis was found to be poor after treatment. J Endod 24:38, 1998
  20. 20. • Basically separated instruments impair the mechanical instrumentation of infected root canals apical to instrument, which contribute to endodontic failure.
  21. 21. Canal blockage and ledge formation • Canal blockage can occur due to accumulation of dentin chips or tissue debris which prevents the instrument to reach its full working length.
  22. 22. • Ledge formation usually occurs by using straight instruments in curved canals. • All these lead to working short of the canal terminus and thus bacteria and tissue debris may remain in non-instrumented area contributing to endodontic failure.
  23. 23. Perforations • It is a mechanical communication between root canal system and the periodontium. • It occurs by – Lack of knowledge of internal anatomy of tooth – Lack of attention while operating – Misdirection of instruments • Prognosis of endodontically treated tooth with perforations depend on many factors J Am Dent Assoc 131:196, 2000
  24. 24. • Location : Depends on its closeness to gingival sulcus. • Time : which has elapsed before defect is repaired • Adequacy of perforation seal • Size of perforation
  25. 25. Incompletely filled teeth • It occurs due to – Incomplete instrumentation – Ledge formation – Blockage – Improper measurements of WL • Several studies have shown poorer prognosis of teeth with underfillings, especially those with necrotic pulps. J Endod 28:454, 2002.
  26. 26. • Remaining infected necrotic tissue, microorganism and their byproducts in inadequately instrumented and filled teeth cause continuous irritation to the periradicular tissues leading to endodontic failure.
  27. 27. Overfilling of root canals • It occurs because of – Apical root resorption – Incompletely formed roots (open apex) – Over instrumentation of root canal system • Overfilling causes continuous irritation of the peri-apical tissues.
  28. 28. • The filling material acts as a foreign body which may generate immunological response. • Several studies have shown biofilms formation on extruded material which contains treatment resistant bacteria. J Endod 30:54, 2004
  29. 29. Corrosion of root canal fillings • Corrosion is the tendency of most of the metals to revert to their lower form by oxidation. • Silver cones have shown to produce corrosion.
  30. 30. • The main area of corrosion of silver cones is coronal and the apical portions, the areas which contact tissue fluids via periapical exudation or saliva. • The corrosion products are cytotoxic and may act as tissue irritants causing persistent periapical inflammation.
  31. 31. Anatomic factors • Presence of overly curved canals, calcifications, numerous lateral and accessory canals, bifurcations, aberrant canal anatomy like C or S shaped canals may pose problems in adequate cleaning and shaping. • These can lead to endodontic failure.
  32. 32. Root fractures • Endodontic failures can occur by partial or complete fractures of the roots. • Prognosis of teeth with vertical root fracture is poorer than horizontal fractures.
  33. 33. Traumatic occlusion • Traumatic occlusion has also been reported to cause endodontic failures because of its effect on periodontium.
  34. 34. Periodontal consideration • An endodontic failure may occur because of communication between the periodontal ligament and the root canal system.
  35. 35. • Also the recession of attachment apparatus may cause exposure of lateral canals to the oral fluids which can lead to reinfection of the root canal system because of percolation of fluids.
  36. 36. Systemic factors • The systemic disease may influence the local tissue resistance and thus interfering with the normal healing process. • When systemic disease is present, the response of the periapical tissues may get intensified if there is increase in concentration of irritants during endodontic therapy.
  37. 37. • Thus severe reaction may occur following cleaning and shaping. • Healing is also impaired in patients with systemic disease.
  38. 38. • Various systemic factors can interfere with success of endodontic therapy are – Nutritional factors – Diabetes mellitus – Renal failure – Blood dyscrasias – Hormonal imbalance – Autoimmune disorders – Opportunistic infections – Aging – Patients on long term steroid therapy • Thus before starting endodontic therapy, a complete medical history is essential to predict the prognosis of the tooth.
  39. 39. Before going for endodontic retreatment following factors should be considered • If patient is asymptomatic even if treatment is not proper, the retreatment should be postponed. • Patient’s needs and expectations. • Strategic importance of the tooth. • Periodontal evaluation of the tooth. • Other interdisciplinary evaluation. • Chair time and cost.
  40. 40. Before performing retreatment following points should be considered • Retreatment may be performed to prevent the potential disease. • To gain access into root canal extensive coronal restoration has to be removed. • Technical problems may result from previous treatment or aberrant canal anatomy. • Even after retreatment sometimes better results may not be achieved.
  41. 41. • Root canal filling materials have to be removed during retreatment. • Prognosis of retreatment could be poorer than the initial endodontic therapy. • Patient might be more apprehensive than with initial treatment.
  42. 42. • Definition : Endodontic retreatment is a procedure performed on a tooth that has received prior attempted definitive treatment resulting in a condition requiring further endodontic treatment to achieve a successful result. Int Endod J 37:272, 2004
  43. 43. Steps in retreatment technique • Access to root canal – Through crown – By removal or crown • Access to apical area – By removal of root canal filling material – By removal of separated instruments. • Reshaping • Antimicrobial treatment.
  44. 44. CORONAL DISASSEMBLY • Clinicians generally access the pulp chamber through the existing restoration if it is functionally well designed, well fitting and esthetically pleasing. • If the restoration is inadequate or if additional access is required, the restoration should be sacrificed.
  45. 45. Factors influencing restoration removal • PREPARATION TYPE • RESTORATION DESIGN & STRENGTH • RESTORATIVE MATERIAL • CEMENTING AGENT • REMOVAL DEVICES
  46. 46. There are several important removal devices which may be divided into three categories: 1. Grasping instruments : K.Y. Pliers and Wynman Crown Gripper K. Y. Plier
  47. 47. • Percussive instruments : Crown-a-Matic and the Coronaflex Coronaflex
  48. 48. • Passive-active instruments : Metalift and the Higa Bridge Remover. Metalift
  49. 49. • Clinicians must clearly define the risk versus benefit with patients before removal of an existing restoration.
  50. 50. • Gaining access through existing restoration helps in : – Facilitating rubber dam placement – Maintaining form, function and esthetics – Reducing cost of replacement • Disadvantages of retaining a restoration include: – Reduced visibility and accessibility – Risks of irreparable errors – Risks of microbial infection if crown margins are poorly adapted
  51. 51. Establish access to root canal system • In some cases post and core needs to be removed for gaining access to the root canal system. • Factors affecting post removal : – Post type – Cementing medium – In occlusal space – Existing restoration – Position of coronal most aspect
  52. 52. TECHNIQUES FOR POST REMOVAL: • Successful post removal requires removing all circumferential restorative material from pulp chamber. • commonly used methods and techniques for removal of post are – Ultrasonic technique – Masserann technique – PRS option
  53. 53. ULTRASONIC METHOD: • Piezo electric ultrasonic systems offers the clinician certain advantages in endodontic disassembly and retreatment. • Generally, the CPR -2 ultrasonic instrument is used on full intensity to remove the remaining core materials periphery to the post.
  54. 54. • CPR - 3,4, & 5 instruments are designed to work in small, restricted and confined spaces. • If space is severely restricted, CPR - 6, 7 & 8 titanium ultrasonic instrument can be used on low intensity.
  55. 55. • Once the post has been fully exposed, rotosonics can be used to loosen and remove the post. • The regular ROTOTIP (Ell man international Hewlett N.Y.) is a high speed Friction grip 6 sided instrument. • When rotated, it produces vibration to loosen and remove the post. • If efforts are unsuccessful, the clinician should select CPR - 1 because of its superb energy transfer.
  56. 56. • CPR-1 has a ball at its working end which is kept in contact with post to maximize energy transfer. • This is used with full intensity and is moved around the post circumferentially with up & down motion.
  57. 57. Removing canal obstructions and establishing patency • Patency of canal can be regained by removing obstructions in the canal which can be in the form of silver points, gutta-percha, pastes, sealers, separated instruments and posts.
  58. 58. Silver point removal • Silver points can be retrieved from canal by following methods: – Using microsurgical forceps – Its use is ideal especially when cone heads are sticking up in the chamber. – Using ultrasonic – In this ultrasonic file is worked around the periphery of silver point to loosen it with vibration.
  59. 59. • Using hedstroem files : In this headstroem files are placed in the canal. • These files are twisted around each other by making clockwise rotation. • This will make grip around silver point which then can be removed.
  60. 60. • Using hypodermic needle which is made to fit tightly over the silver point over which cyanoacrylate is placed as an adhesive. • When it sets, needle is removed with pliers. • By tap and thread option using microtubular taps from post removal system kit. • By using instrument removal system.
  61. 61. Gutta-percha removal • The relative difficulty in removing GP varies according to the – Canal length – Canal c/s dimensions – Canal curvature. • Regardless of the technique, its best removed in a progressive manner to prevent displacement of irritants periapically.
  62. 62. • Dividing the root into three parts G.P. is initially removed from canal in coronal 1/3, then middle 1/3 & finally eliminated from apical 1/3 of the canal. • In canals that are relatively large & straight, single cones can be removed in one motion.
  63. 63. • Single cone: • They can be removed by using – A headstroem file – Tweezers – Steiglitz forceps – Endosonics.
  64. 64. • H file method : largest H-files that will fit the cone should be used to reduce the risk of fracture. • The file is gently screwed into the canal (obturated) until resistance is met. • At this point the instrument is withdrawn from canal along with G.P. cone.
  65. 65. • Endosonics can also be used. • It loosen the cement around the single cone, there by aiding removal. • If cones are accessible they can be gripped with Tweezers / Steiglitz forceps for removal.
  66. 66. • CONDENSED GUTTA PERCHA • Condensed G.P. can be removed using a combination of – Heat – G.G drills – Niti rotary instruments – Hand instruments such as H files – Solvents – Ultrasonic – Paper points
  67. 67. Heat • Traditionally power source in conjunction with specific heat carrier instrument such as Touch - N - Heat / system B has been used to thermo soften & remove fragments of G.P from root canal systems.
  68. 68. • Disadvantage: It limits its ability to place into under-prepared systems and around pathways of curvature. • Technique: Activate the instrument until it is red hot, then place it into the coronal most aspect of G.P.
  69. 69. • The heat carrier is then deactivated. • And as it cools, withdrawal will result in removal of attached fragment of G.P. • The process is repeated as long as it continues.
  70. 70. Heat & Instrument removal • In this method a hot instrument is placed into G.P. & immediately with drawn to heat soften the material . • A size 35, 40/45 H-file is then selected gently screwed into the thermo softened mass.
  71. 71. • When GP cools, it will freeze on flutes of file. • In poorly obturated canals, removing the file can, at times, eliminate the engaged G.P in one motion. • This technique is good in those cases where G.P. extends beyond the foramen.
  72. 72. Solvents: • Solvents include chloroform, xylene, rectified turpentine, chloroform & eucalyptus oil. • There has been some concern expressed in literature about carcinogenic potential of the chloroform. • Rectified turpentine is a useful alternative. • Eucalyptus is heated and used in order to be as effective as chloroform.
  73. 73. • Solvents should be used only in small amounts and must be contained with in R.C. system. • Using solvent too early in treatment leaves a messy layer of dissolved G.P. coating the root canals & pulp floor, which can be difficult to remove. • If most of G.P. has been removed mechanically, then a minimal amount of solvent is required to dissolve the remaining.
  74. 74. FILE & CHEMICAL REMOVAL • It is the best option to remove G.P from small & curved canals. • The technique involves filling the pulp chamber with chloroform, selecting a appropriate size file & gently picking into chemical softened G.P. • Initially, a size 10 or 15 SS file is used to pick into G.P. occupying the coronal 3rd.
  75. 75. • Frequent irrigation creates a pilot hole and sufficient space for the serial use of larger file to remove G.P. • This method is continued until G.P is no longer evident on cutting flutes when the files are with drawn from solvent filled canal. • After G.P. has been removal from coronal 3rd, repeat the technique in middle 1/3 & finally apical 1/3. • This progressive removal technique helps prevent extrusion of chemically softened material apically.
  76. 76. Paper point & chemical removal • G.P. & most sealers are miscible in chloroform & once in solution can be absorbed and removed with appropriately sized paper points. • Drying solvent filled canals with paper point is known is “Wicking” & is always the final step of G.P. removal. • This wicking action is essential in removing residual G.P. & sealer out of fins, cul de sacs & aberrations of R.C. systems.
  77. 77. • In this technique, the canal is 1st flushed with chloroform & solution is then absorbed & removed with appropriately sized paper points. • Paper points “wick” by pulling dissolved material from periphery to central.
  78. 78. • Process is repeated as long as it continues to be visibly productive. • After chloroform wicking procedures, canal is flushed with 70% isopropyl alcohol, & wicked for further elimination of chemically softened G.P. residues.
  79. 79. Rotary Removal • Active Niti rotary files (dentsply) are the most effective & efficient instruments for G.P. removal. • Disadvantages: Should be used with caution in under-prepared canals & are generally not selected for removing G.P in canals that do not accept them passively.
  80. 80. • When attempting for removal, the R.C. should be divided to 3 parts. • Select appropriately sized rotary instrument that will fit passively in these canals. • To soften & engage G.P. mechanically rotary instrument must turn at speeds between 1200-1500 RPM. • Rotational speed is based on friction required to mechanically soften G.P.
  81. 81. ULTRASONIC • Piezoelectric ultrasonic system represents a useful technique to rapidly remove G.P. • Ultrasonic instrument produces heat and thermosoftens G.P.
  82. 82. • Specially designed ultrasonic instrument are carried into canals, that have sufficient shape to receive them. • This method will float G.P coronally into pulp chamber where it can be sub subsequently removed.
  83. 83. G.G.Drills / Burs: • G.G. drills are extremely efficient for removing G.P. from coronal parts of well compacted root canals. • They need to be rotated in a slow speed hand piece generating frictional heat that will aid G.P. removal.
  84. 84. Carrier Based Gutta Percha Removal • Techniques are same as for G.P & silver point. • Initially it used to be metal & file like • Yet over the past several years they have been manufacturing easier to remove plastic materials. • After careful access and complete circumferential exposure of the carrier, suitable grasping pliers are selected and a purchase is obtained on the carrier.
  85. 85. • Carrier is grasped with the pliers and removal is attempted using fulcrum mechanics rather than a straight pull out of the tooth. • Ultrasonic tip can be used to produce heat and thermosoften the G.P. • The activated ultrasonic instrument is gently moved apically and carrier is often times displaced and floated out coronally. • Once the carrier is removed, the remaining G.P. can be removed using solvents.
  86. 86. Paste removal • When evaluating a paste case for retreatment, it is useful to chemically understand that pastes can generally be divided into • a) Soft, Penetrable & Removable • b) Hard, impenetrable, unremovable
  87. 87. • However, it is important to understand that because of the method of placement, the coronal portion of paste in the canal is most dense. • Abrasive coated ultrasonic instruments can be used for the safe removal of hard & impenetrable paste. • Heat, end-cutting rotary NiTi instruments and small sized hand files with solvents such as Endosolv R and Endosolv E are used to remove soft & penetrable paste.
  88. 88. Broken Instrument Removal • During R.C. preparation procedures, the potential for instrument breakage is always present. • Many clinicians associate “Broken instrument” with separated files, but the term could also apply to a silver point, a lentulospiral, a G.G. drill, or any obstruction left behind in the canal.
  89. 89. • Historically, the consequences of leaving / by passing broken instruments have been discussed and varieties of approaches for removing these obstructions have been presented. • Because of technologic advancements in vision, ultrasonic instrumentation and microtube delivery methods, separated instruments can usually be removed.
  90. 90. Factors influencing broken instrument removal • Cross sectional diameter, length & curvature of R.C. – If 1/3 of overall length of obstruction can be exposed  can be removed. – If its just in straight portion of canal - can be removed – When the separated instrument lies partially in the canal curvature still possible to remove. – If entire segment is apical to curvature - safe access cannot be accomplished and removal is not possible.
  91. 91. • Type of material comprising the obstruction – S.S. files - easier to remove as they do not # during removal process. – NiTi files - may explode and break again due to heat build up caused by ultrasonic devices.
  92. 92. Steps • 1st step  Coronal access  • High speed friction grip surgical length burs are selected to create straight line access to canal orifice • 2nd step  Radicular Access  • If radicular access is limited - hand files are used serially (small to large) to create sufficient space to safely introduce G.G. drill’s.
  93. 93. • These G.G drills are then used like “brushes” to create additional space and maximize visibility coronal to obstruction. • If greater access required, then bud shaped tip of GG can be modified and used to create a circumferential “staging platform”.
  94. 94. Staging Platform – This is done by selecting a G.G. with maximum c/s diameter that is slightly larger than the visualized instrument. – The bud of G.G. is altered by cutting it perpendicular to long axis at its maximum C/S diameter. – The “modified” G.G. is rotated at 300 rpm, gently carried to canal and directed apically, until it lightly contacts the coronal aspect of obstruction.
  95. 95. • This clinical action creates a small “Staging Platform” that facilitates the insertion of zirconium nitride coated ultrasonic tips • 3rd Step  Removal • Before performing any removal especially when treating a multi-rooted teeth the potential problem is that the #ed segment floating out of one canal and finding its way into one of the other orifice.
  96. 96. • So, to prevent this it is wise to place cotton into the other orifice. • Once the ultrasonic instrument is selected, based on depth of broken file and space availability, the instrument should be activated at the lowest power setting. • Dry field is preferred, so that clinician has constant vision between tip and broken instrument.
  97. 97. • Then the selected tip is moved lightly in counter clockwise direction around the obstruction and trephines around the coronal few mm of obstruction. • Typically during ultrasonic use  the obstruction begins to unwind, loosen and spin. • On occasion where this ultrasonic technique doesn’t work the microtube device can be selected to engage and remove the obstruction mechanically.
  98. 98. Apical Obstructions / Blockage • When canals have been under filled, obstructive calcification might be found apical to unfilled portion. • After coronal pre-enlargement and relocation of the canal orifice with G.G. drills, the coronal part of the canal is copiously irrigated with NaOCl and then thoroughly dried with paper points.
  99. 99. • At this stage if possible the intracanal anatomy should be inspected carefully under microscope. • Then a small size precurved K file in association with a lubricating gel is inserted with a slight pecking motion to try to find a catch. • As long as catch is felt at tip of K file, apical progression should be continued and checked periodically with radiograph until the canal terminus is launched.
  100. 100. Ledges: • Often a ledge has been formed at the end of the previous obturation of the canal. • Most of the time ledge is the result of an inadequate angle of access to the R.C. • Preflaring the coronal portion of the canal with K files and relocating the canal with G.G. are preliminary steps to by pass.
  101. 101. • Flood the canal with irrigating solution. • Select a no. 10 S.S. K file place a sharp 1mm curvature at the tip and orient the rubber stopper toward the file tip. • Insert the file in the canal with the tip directed toward the canal curvature.
  102. 102. • Pick gently with very short strokes, searching for a catch. • This procedure will remove the irrigant and help to disintegrate the dentine mud. • If Unsuccessful, rebend the file tip and repeat the same procedure while slightly reorienting the tip. • When a catch is felt, it is moved in and out of the canal utilizing ultra-short push-pull movements.
  103. 103. • When the file moves freely, it may be turned clockwise on withdrawal to smoothen or eliminate the ledge.
  104. 104. Conclusion • Training proctol and technology allow clinicians to greatly expand their abilities in non surgical retreatment. Clinicians need to weigh risk versus benefit and recognize that at times surgery / extraction might be in patient’s best interest. • When choosing non surgical retreatment careful assessment and treatment planning with each case is the corner store of success.
  105. 105. References

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