Restoration of endodontically treated tooth /certified fixed orthodontic courses by Indian dental academy


Published on

The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit ,or call

Published in: Education
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Restoration of endodontically treated tooth /certified fixed orthodontic courses by Indian dental academy

  4. 4. INTRODUCTION  Initially only extraction  From past 20 – 30 years, increased interest in restoring.  It is well known that with proper endodontic treatment and adequate restoration, pulpless teeth can serve indefinitely as an integral part of the dental apparatus, provided the supporting structures are not compromised.
  5. 5.  From the time of Pierre Fauchard till date a wide range of materials, techniques and designs have been described to restore endodontically treated teeth.  However, there is no clear consensus regarding an ideal system, this is because each tooth presents with a unique requirement.  A thorough understanding of the proper use of posts and cores will enable clinicians of today to provide an optimum restoration that uniquely balances between maximizing retention of the tooth while minimizing the risk of failure.
  6. 6. HISTORY AND EVOLUTION  Restoration of endodontically treated tooth by a post to retain a crown dates back more than 250 years.  In 1747, Pierre Fauchard a French dentist used “Tenons” which were metal posts (Gold or silver) into the roots of teeth to retain bridges. He used heat softened adhesive called MASTIC.
  7. 7.  Later wood replaced metal as the post material, and the “Pivot Crown”, a wooden post fitted to an artificial crown and to the root canal became popular. But they led to repeated episodes of swelling and pain.  In mid 1800 –Dr.F.H.Clark – developed a “spring loaded dowel” a retentive device consisting of a metal tube in the canal and a split metal dowel which was inserted into it. They also had channels for continuous suppuration from the underlying tissues.
  8. 8.  G.V. Black developed porcelain fused to metal crown held in by a screw inserted into a canal filled with gold foil.  In 1878 , the “Richmond Crown”, a single piece post-retained crown with a porcelain facing was engineered to function as a bridge retainer.
  9. 9.  During the 1930s, the custom cast post and core was developed to replace the one piece post crowns, because of their drawback of using in diverging roots and difficulty in removal and replacement of FPD crowns.  In 1960s prefabricated posts were introduced.  1990 Duret et al described a non metallic material for the fabrication of posts based on carbon fibres reinforcement principle.
  10. 10. Are endodontically treated teeth different
  11. 11.  Moisture loss  Architectural changes  Biomechanical behavior  Dentinal toughness  Collagen alteration  Altered esthetic characteristics  Loss of Neuro-sensory feedback
  13. 13. ENDODONTIC EVALUATION  Good apical seal as revealed by radiographs.  No tenderness on percussion  No apical sensitivity  No exudate  No fistula  No active inflammation.
  14. 14. PERIODONTAL EVALUATION  Periodontal health is critical to the long term success of teeth that have been endodontically treated and restored.  Periodontal condition must be assessed before endodontic treatment, and the effect of planned restoration on the attachment apparatus must be considered.  Any structural defects of teeth should be considered that jeopardize coronal restoration.  Extensive caries, tooth fracture, previous restoration, perforation and external resorption can destroy tooth structure at the level of the periodontal attachment.
  15. 15. Biological Width Biological Width Encroachment
  16. 16. RESTORATIVE EVALUATION      Depends on, Amount of remaining tooth structure Tooth type Morphology Occlusal and prosthetic forces Periodontal support
  17. 17. ESTHETIC EVALUATION  Potential esthetic complication should be investigated before initiation of endodontic therapy.  Thin gingiva may transmit a shadow of dark root through the tissue.  Metal or dark carbon fiber post and amalgam placed in the canal can result in unacceptable gingival discoloration from the underlying root.
  18. 18.  The translucency of All-ceramic crowns must be considered in the selection of dowel and build-up materials.  Tooth colored carbon fiber glass-reinforced composite resin, or zirconia posts can be used in esthetic areas. Similarly, tooth colored, rather than opaque, composite core material should be selected for esthetics.  An intact endodontically treated tooth requires critical control of endodontic materials in the coronal third of the canal and pulp chamber in order to maintain its color and translucency.
  19. 19.  Gutta percha discoloration can be visible in the coronal aspect of an endodontically treated tooth and should be limited to an apical level in the root.  Endodontic and restorative materials in these esthetically critical cases must be selected to provide the best health service with the minimum of esthetic compromise.
  20. 20. TREATMENT GOALS  to maintain the coronal and apical seal of the root canal filling material  to protect and preserve remaining tooth structure  to provide a supportive and retentive foundation for the placement of a definite restoration  To restore function and esthetics.
  21. 21. Post The post is defined as a relatively rigid, metallic or non metallic restorative material inserted into the root canal of a nonvital tooth to aid in retention of a core component and to transmit the forces .
  22. 22. INDICATIONS FOR POST  To retain the restoration  To protect remaining tooth structure  Marginal integrity  To stabilize radicular fractures
  23. 23. CONTRAINDICATIONS FOR POST  Abnormal root anatomy.  Extensive caries including root caries.  Perforations.  External resorption.  Short roots.  Dilacerated roots.  Blunderbuss canal.  Young patients with coronal fracture, with incomplete root formation.  Patients with poor oral hygiene.
  24. 24. Ideal requirements of post  Simple and safe.  Biocompatible.  Should support the core and crown.  Should provide resistance for stresses.  Maximum protection of root.  Adequate retention within the root.  Pleasing esthetics, when indicated.  High radiographic visibility.  Easily removable.  Less expensive.
  25. 25. Classification Various classifications given by, - Ingle and Bakland - Shillinburg and Kessler - Robbins
  26. 26. depending upon the preparation  custom made posts  pre-fabricated posts depending upon material used  metallic posts eg; stainless steel, brass, Ni-Cr, CoCr, Ti, gold-platinum  non-metallic posts eg; composite and ceramic post.
  27. 27. depending upon the flexibility  stiff  flexible – flexi post depending upon the esthetics  esthetic  non-esthetic depending upon the retention  Active –eg; flexi-post, Kurer anchor  passive – cast post, smooth tapered post, parapost
  28. 28. depending upon the design a. tapered - Smooth sided posts - Serrated posts - threaded posts b. parallel - Smooth sided - Serrated posts - threaded post
  29. 29. Pre-fabricated posts Tapered, Smooth-Sided Posts - The oldest and most widely used design. Eg : Kerr Endopost, Mooser post and all custom-cast posts. - least retentive of all post designs, Used low functional loads -wedging pressure upon roots during function. -Used when other designs are contraindicated -self-venting and easily cemented, no Hydrostatic pressures because a taper does not act as a piston.
  30. 30. Tapered Posts with Self-Threading Screws Eg : Dentatus - More retentive……gains its retention by spreading into the dentin as it self-threads. - Sets up fracture lines as it “cuts” and spreads its way into the dentin. - The wedge configuration of the screw design is accentuated under load when occlusal forces are added to the installation forces described above. .
  31. 31. Parallel-sided Posts ex; Whaledent posts which has three post designs: Para-Post, Para-Post Plus, and the Unity System. All are passive, parallel, vented posts made of either stainless steel or titanium. - provides substantially greater retention than the smooth tapered design. Consequently, these posts can be effectively employed in situations where higher applied forces are expected.
  32. 32.  The Para-Post has a vertical groove cut along the length of its serrations, allowing axial venting. This design allows cement to escape….  Provide the most equitable distribution of masticatory forces of all available post designs. Avoids the wedging effect of tapered posts. The transfer of occlusal forces of the tooth occurs via the cement layer, which serves to buffer the forces. Together, these two factors result in a uniform distribution of stresses in the supporting tooth.
  33. 33. CARBON FIBRE  Introduced in 1990 by Duret and associates in France.  They consist of continuous, unidirectional, pyrolytic carbon / graphite fibres reinforced in an epoxy resin matrix with 64% carbon.  Parallel sided, smooth post, wider coronally and tapers towards the apex.
  34. 34. ADVANTAGES      Better strength High flexibility Easy retrievability Better redistribution of stresses High fatigue resistance
  35. 35. DISADVANTAGES:  Aesthetics– the black color of post has a negative effect on the final aesthetic result of all ceramic crown  Poor adhesion with composite causing failure of post / core interfere.  Lack of radio opacity
  36. 36. Zirconia posts  Compatible with all ceramic crown  Made up of tetragonal zirconium polycrystals.  High flexural strength, fracture toughness, radiopaque.  Better adhesion with composite core materials.
  37. 37. WOVEN-FIBRE COMPOSITE MATERIALS  Use of cold glass plasma treated polyethylene woven fibres embedded in conventional resin composite  Consists of woven fibre ribbons
  38. 38. THE CORE The core is defined as a restorative material placed in the coronal area of a tooth to replace the missing coronal structure. The core is anchored to the tooth by extending into the coronal aspect of the canal, or through the endodontic post.
  39. 39. Ideal properties of the core material  High compressive and tensile strength.  High modulus of elasticity (rigidity).  High fracture toughness.  Dimensional stability.  Ease of manipulation.  Short setting time.  The ability to bond to both tooth and post.  Biocompatibility.  Inert (no corrosion).  Natural tooth color, when indicated.  Low plastic deformation.  Low cost.
  40. 40. Core materials • Cast core • Amalgam • Composite • Glass ionomer cement • Resin modified glass ionomer cement.
  41. 41. Cast core This has been the traditional means for restoring endodontically treated teeth. The cast core is an integral extension of the dowel and the cast core and hence does not depend on mechanical means for retention to dowel. This construction avoids dislodgement of the core and crown from the dowel.
  42. 42. Amalgam core Dental amalgam is a traditional core build-up material with a long history of clinical success
  43. 43. Advantages  Not especially technique sensitive.  Strong in bulk.  Sealed by corrosion products.  High compressive strength, high tensile strength, high modulus of elasticity.  Withstands functional stresses thus protecting the residual tooth structure, cement and crown margins.  It is easily manipulated.  Simple to use and economical.  Coronal radicular stabilization increases the retention of amalgam cores.
  44. 44. Disadvantages  It needs 24 hours to set before final tooth preparation.  Weak in thin sections.  Mercury content may be of concern to some patients and dentists.  Potential electrolytic action between core and metal crown.  Not intrinsically adhesive.  Corrosion and subsequent discolouration of gingiva or remaining dentin.
  46. 46. Advantages  Strong compressive strength.  Can be used in a thinner section than amalgam.  Fast setting (either light or chemically cured).  Does not always need a matrix during placement  Avoids mercury controversy.  Ease of manipulation.
  47. 47. Disadvantages  Highly technique sensitive.  Relies on multi-stage dentin bonding requiring effective isolation.  Dentin bond can be ruptured by polymerization contraction.  Minor dimensional changes caused by the co-efficient of thermal expansion (3 times higher than tooth) and water absorption – not usually clinically significant.  difficult to distinguish between tooth and core during preparation.
  48. 48. Glass-Ionomer core Advantages Useful for small buildups or to fill undercuts in prepared teeth. Fluoride release - anticariogenic quality but does not guarantee freedom from secondary tooth decay. Intrinsically adhesive. Similar coefficient of thermal expansion to tooth.
  49. 49. Disadvantages  Considerably weaker than amalgam and composite.  Low strength and fracture toughness results in brittleness, which contraindicates the use of G.I.C. build ups in thin, anterior teeth or to replace unsupported cusps.  Low retention to preformed metal dowels.  Tendency to crack worsened by early instrumentation.  It is soluble, sensitive to moisture.  Adhesive failure can result from contamination of the tooth surface with cutting debris, saliva, blood or protein.  Not strong enough for a core for an abutment tooth.
  51. 51. CONSERVATION OF TOOTH STRUCTURE  Preparation of canal  Preparation of coronal tissue
  52. 52. Preparation of canal     When creating post space, great care must be used to remove only minimal tooth structure from canal. Excessive enlargement can perforate or weaken the root, which then may split during cementation of post or subsequent function. Thickness of remaining dentin is the prime variable in fracture resistance of the root. Larger diameter post caused more fractures then smaller posts, and also induced more stresses.
  53. 53. 1) Adequate apical seal 2) Minimal canal enlargement 3) Adequate Post Length 4) Positive horizontal stop 5) Vertical wall to prevent rotation 6) Extension of final restoration margin on to sound tooth structure
  54. 54. Preparation of coronal tissue Endodontically treated teeth have often lost much coronal tooth structure as a result of caries, previously placed restoration, preparation of endodontic access cavity or trauma. If cast post and core is to be used, further reduction is needed to accommodate a complete crown and to remove undercuts from the chamber and internal walls. This may leave very little coronal dentin.
  55. 55. Preservation of coronal tooth structure is necessary to reduce stress concentration at gingival margins which is also necessary for creating a ferrule. Crown lengthening does provide a ferrule but it results in an unfavorable crown to root ratio thus increasing the leverage on the root during function.
  56. 56. RETENTION FORM Affected by      Preparation geometry Post length Diameter Dowel design Luting agents
  57. 57. Preparation geometry  In circular root – parallel post with minimal preparation.  In elliptical root – space between the post and the canal wall, - increased preparation weakens the tooth - retention by threaded post minimizing the stresses created.
  58. 58. Post length   As post length increases, retention increases, however the relationship is not linear, an extremely long post may damage the seal of the root canal fill or risk root perforation if the apical third is curved or tapered. Ideally the post should be as long as possible without jeopardizing the apical seal or the strength or integrity of the remaining root structure.
  59. 59.
  60. 60. Various concepts of post length  Preservation of 3-5mm of gutta percha at apex.  Equal to inciso-cervical or occluso-cervical length of crown.  The post should be longer than the crown.  The post should be 1 ⅓ the length of the crown.  The post should be certain fraction of the length of the root such as one half, two third, or four fifth.  The post should end halfway between the crestal bone and root apex.  The post should be as long as possible without disturbing apical seal.
  61. 61. Post diameter Increasing the diameter of the post does not provide a significant increase in the retention of the post, however it can increase the stiffness of the post at the expense of the remaining dentin and the fracture resistance of the root.
  62. 62. Post design A serrated or roughened post is more retentive than a smooth one, and controlled grooving of the post and root canal considerably increases the retention of tapered post.
  63. 63. Retentiveness of dowels with regard to dowel configuration Post configuration Most retentive ↓ Least retentive Parallel threaded Tapering threaded Parallel serrated Parallel smoothsided Tapering smoothsided Example Kurer Crown Saver Dentatus, Obturation screw Parapost Stainless steel wire Gold casting
  64. 64. Luting agents : Retention provided by luting cements: Zinc phosphate cement < Polycarboxylate cement < G.I.C < Adhesive resin cement   Precaution : Resin cements are affected by eugenol-containing root canal sealers, which should be removed by irrigation with ethanol or etching with 37% phosphoric acid if the adhesive is to be effective. Removing the smear layer with 17.7% EDTA and 5.25% NaCl enhanced retention.
  65. 65. Luting method A. Cement placed on post B. Cement Placed in the canal C. Cement Placed both on the post and in the canal A B C
  66. 66. RESISTANCE FORM  Stress distribution  Rotational resistance
  67. 67. Stress distribution  Studied by photo elastic materials, strain gauges, finite element analysis.  The main function of post and core is to improve resistance to laterally directed forces by distributing them over as large an area as possible.  Excessive internal preparation of root weakens it, and the possibility of failure increases.  The greatest stress concentration is found at the shoulder, particularly interproximally, and at the apex. Dentin should be conserved in these areas if possible.
  68. 68. - Stresses are reduced as post length increases. - Parallel-sided posts may distribute stress more evenly than tapered posts, which may have a wedging effect. However, parallel posts generate high stresses at the apex. - Sharp angles should be avoided because they produce high stresses during loading.
  69. 69. - High stress can be generated during insertion, particularly with smooth, parallel sided posts that have no vent for cement escape. - Threaded post can produce high stress concentration during insertion and loading, but they have been shown to distribute stress evenly if posts are backed off a half turn. - The cement layer results in a more even stress distribution to the root with less stress concentration.
  70. 70. Rotational resistance  not a problem in areas where sufficient coronal tooth structure remains, because rotation is usually prevented by a vertical coronal wall. In areas where coronal dentin has been completely lost, a small groove placed in the canal can serve as an anti-rotational element.  The groove is normally located where the root is bulkiest, usually on the lingual aspect. Antirotational groove
  71. 71.  Slots or Cloverleafs - It is made at the orifice with a thin, pointed, tapered diamond stone or No.557 carbide bur.  Auxiliary pins  Preparing a cavity between the canal wall and the post and condensing the amalgam. Slots or Cloverleafs
  72. 72. Preparation of canal space and tooth : It is a 3 stage operation :  Removal of endodontic filling material to the appropriate depth.  Enlargement of the canal.  Preparation of the coronal tooth structure.
  73. 73. Removal of the Endodontic Filling Material  It is recommended that the root canal system should first be completely obturated and then space made for a post. This will ensure that the lateral canals are sealed.  With a heated endodontic plugger.  With a rotary instrument
  74. 74. Enlargement of the Canal - Peeso reamers or a low speed drill. - The purpose is to remove undercuts without excessively enlarging the canal to receive prefabricated posts - in excessively enlarged or flared canal, cast posts are preferred.
  75. 75. For Pre-fabricated Posts - Enlarge the canal one or two sizes with a drill, endodontic filing or reamer that matches the configuration of the post - In case of threaded post, the appropriate drill is followed by a tap
  76. 76. For Custom-made Posts  In noncircular or enlarged canal, preparation to receive the pre-formed posts will lead to perforations  Often very little preparation will be needed for a custom-made post.  However, undercuts within the canal should be removed and some additional shaping is usually necessary.  Careful to avoid perforation in molars
  77. 77. Preparation of Coronal Tooth Structure After the post space has been prepared, the coronal tooth structure is reduced for the extracoronal restoration.  Ignore any missing tooth structure and prepare the remaining tooth as though it was undamaged.  The facial surface (in anteriors) should be adequately reduced for good esthetics.  Remove all undercuts that will prevent removal of pattern.  Preserve as much tooth structure as possible.  Prepare the finish line at least 2mm gingival to the core. This establishes the ferrule.  Complete the preparations by eliminating sharp angles and establishing a finish line.
  78. 78. Ferrule effect It originates from combining the Latin for Iron (ferrum) . Without ferrule With ferrule
  79. 79. Requirements •A maximum of 2mm of dentin axial wall height. •Parallel axial walls. •Metal must totally encircle the tooth. •It must be on sound tooth structure. •It must not invade the attachment apparatus.
  80. 80. Insufficient crown length – What to do? a. Insufficient crown height b. No ferrule effect c. Ferrule effect achieved after crown lengthing
  81. 81. Surgical crown lengthening Gingivectomy Procedure Insufficient Crown Height Crown Height Increased and Crown Given Gingivectomy Done
  82. 82. Surgical Crown Lengthening Insufficient Crown Height Sulcular Flap Elevated and Apically Repositioned Crown Height Increased (Front View) Crown Height Increased (Occlusal View)
  83. 83. ORTHODONTIC TOOTH EXTRUSION Inadequate Crown Height Eyelet Post Cemented and Tooth Pulled Out Sulcular fiberotomy done every 4 days 3 weeks after rapid eruption. root structure exposed Adequate
  84. 84. Pre-eruption Radiograph Post- eruption Radiograph
  85. 85. PREFABRICATED POST AND CORE TECHNIQUE Post Space Preparation Post adjusted Post Space Prepared Luting Pre Fabricated Post Tried-in cement placed in canal
  86. 86. Post cemented Completed Core Core built Crown Cemented
  87. 87. Fabrication of Custom made post  Direct technique  Indirect technique
  88. 88. Direct technique Materials  Inlay wax  Thermoplastic resin  Autopolymerizing resin  light polymerized resin
  89. 89. Using auto polymerising resin Lubricate canal Select a loose fitting plastic dowel. Should extend to full depth of prepared canal Notch it add resin only to canal orifice first or add resin on post using bead-brush Technique Or Mix some resin , roll in cylinder shape and introduced in canal by Pushing with monomer moistened dowel.
  90. 90. Do not allow resin to harden fully Loosen and reseat it several times Once polymerized remove it Form apical part of post by adding additional resin  reseat and removing Care not to lock it in canal
  91. 91. add additional resin for core formation Slightly overbuild the core and let it polymerize Shape the core with carbide finishing burs.
  92. 92. Using thermoplastic resin material Plastic rod selected (Merritt EZ post system) Should extend to full depth of prepared canal Be loose Should be 1.5-2mm above the occlusal surface
  93. 93.  Lubricate canal  Heat thermoplastic material  Apply on apical aspect of rod
  94. 94. Insert the rod Wait for 5-10 secs reseat Inspect for completeness
  95. 95. Core build up using autopolymerizing resin Trimmed to ideal tooth preparation form Final preparation.
  96. 96. Indirect procedure Orthodontic wire bend in J shape Verify fit loosely fit, extend to full depth If too tight impression will tear away
  97. 97.  Coat wire with adhesive  Lubricate canal (die lubricant)  Fill canal with elastomeric impression material (using lentulo spiral)  Seat wire to full length  Syringe some impression around teeth, insert impression tray
  98. 98. Remove impression Pour cast
  99. 99.  In lab, select a plastic post (toothpick)  Using impression as guide make sure it extend to full depth
  100. 100. Lubricate stone cast Add inlay wax in increments on post Pattern fabricated
  101. 101. Add wax core and shape it
  102. 102. Direct technique for posterior
  103. 103. Indirect pattern for multirooted teeth (split core)
  104. 104.
  105. 105. TEMPORIZATION AFTER POST PREPARATION Post spaced prepared Cotton wool placed till the apical part of the preparation over the remaining gutta percha to prevent temporary cement uniting with the root filling cement Pre fabricated post built up with acrylic and with temporary Core temporary crown given cement
  106. 106. Investing and casting  The post-core pattern is sprued on the incisal or occlusal end.  1.0 to 2.0 cc of extra water is added to the investment and a liner is omitted to increase the casting shrinkage. This results in a slightly smaller post that does not bind in the canal, and it also provides space for the cement.  When resin is used, the pattern should remain for 30 minutes longer in the burnout oven to ensure complete elimination of the resin
  107. 107. POST REMOVAL  When there is failure of post-endodontic treatment, there arises a need to remove to post to facilitate non-surgical retreatment.  In other instances, the endodontic treatment may be successful but to improve design mechanics, or aesthetics of a new restoration removal of the existing post may be necessary.
  108. 108. Methods of removal of posts Mechanical methods. Ultrasonic methods.
  109. 109. Hemostat Forceps and Stiglitz Forceps
  110. 110. Masseran Kit Mini Masseran Kit Trepan Bur Masseran Extractor
  111. 111. Trepan Bur placed over post Technique of removal of Post Trepan Bur adjusted over Post Canal after post removal
  112. 112. Post removal using Post Puller
  113. 113. Fiber Post Removal Kit Eggler Post Remover
  114. 114. Ultrasonic methods
  115. 115. SUMMARY AND CONCLUSION  Although restoration of endodontically treated teeth has been rationalized, information from controlled long term clinical trials is still needed.  As much tooth structure must be preserved as possible and post and core is basically used to provide retention and support for a cast restoration.  There is not one post, core or final restoration that can be used in all – clinical situations. So we have to learn with these variables and understand the basic concepts of how to use them to maximum advantage.
  116. 116. BIBLIOGRAPHY  Rosenstiel, Land and Fujimoto. Contemporary Fixed Prosthodontics. 2nd Ed.; Mosby, St. Louis, 1995.  Shillinburg. Fundamentals of Fixed Prosthodontics. 3rd Ed.; Quintessence, Chicago, 1997.  Tylman’s Theory and Practice of fixed Prosthodontics. 8th edition.  Ingle and Bakland. Endodontics. 4th Ed; Williams and Wilkins, Malvern, 1994.
  117. 117.  Cohen and Burns. Pathways to the Pulp. 8th Ed; Mosby, St. Louis, 2002.  Charles J , Goodame, DDS, MSD and Kenneth J. Splnik, DDS, The Prosthodontic Management of Endodontically Treated Teeth: A Literature Review. JProsthod 1994;3:243-250.  Vidyashree V. Nandini, V. Venkatesh Current concepts in the restoration of endodontically treated teeth, The Journal of Indian Prosthodontic Society;June 2006;Vol 6;Issue 2
  118. 118.