Restoration of endodontically treated teeth 1 /certified fixed orthodontic courses by Indian dental academy


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Restoration of endodontically treated teeth 1 /certified fixed orthodontic courses by Indian dental academy

  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education
  3. 3. CONTENTS Introduction. 2. Definitions 3. History 4. Review of literature 5. Changes in endodontically treated teeth. 6. Pretreatment evaluation. 1.
  4. 4. 7. Treatment planning for restoration of endodontically treated teeth. 8. Principles of tooth preparation. 9. Basic components used in restoration of endodontically treated tooth. a) Dowel i) Ideal properties ii) Classification iii) Retentive, protective and esthetic qualities
  5. 5. iv) Recent advances b) Core i) Desirable physical characteristics ii) Various materials used in core fabrication c) Coronal coverage 10) Procedure for tooth preparation of endodontically treated teeth a) Guttapercha removal b) Post space prepration 
  6. 6. c) Preparation of coronal tooth structure 11) Custom cast and core 12) Provisional restoration 13) Bleaching as an treatment option 14) Summary 15) Conclusion 16) References
  7. 7. Core The core consists of restorative material placed in the coronal area of a tooth. It replaces lost coronal tooth structure and provides retention for crown
  8. 8. Desirable physical characteristics:  High compressive strength  Dimensional stability  Ease of manipulation  Ability to bond to both tooth and dowel.
  9. 9. Cast core Cast metal dowel and core traditional way of restoring . Core is integral extension of dowel. Does not depend upon mechanical means for retention to dowel.
  10. 10. Advantage Avoids dislodgement of core and crown from dowel and root when minimal tooth structure remains Indirect procedure can be used making restoration of posterior teeth easier.
  11. 11. Disadvantage 1. Higher rate of root fracture than preformed dowels (JPD 1999;81;262) 2. Needs extra appointments 3. Casting defect- porosity at the dowel –core interface susceptible to fracture
  12. 12. Casting a core to preformed dowel made of S.S. Restoration not sufficiently strong to withstand clinical forces.
  13. 13. Amalgam core Advantage 1. high compressive strength, high tensile strength and high modulus of elasticity. 2. stable to thermal and functional stress transmits minimal stress to residual tooth structure and cement and crown margins.
  14. 14.  Amalgam cores  highly retentive when used as coronal and radicular restorations or with a preformed SS dowel in posterior teeth. require more force to dislodge than cast dowel cores.  Relatively stable in the presence of water offers resistance to leakage once it has been in place for a period of time due to the sealing effects of its corrosion products.
  15. 15.  Amalgam is easily manipulated  Bonded amalgam procedures can improve the seal at the tooth and alloy junction.  Placement of a fast-setting, high-copper alloy core permits final crown preparation at the initial operative appoint-ment, although the early strength is low.
  16. 16. Disadvantage  Potential for corrosion and subsequent discoloration of the gingiva or remaining dentin.  Require second appointment for tooth preparation.
  17. 17. Composite resin core. Advantages  easy to manipulate  High compressive strength.  Preparation for the final restoration  accomplished during the core placement appoint-ment.
  18. 18. Disadvantages  Ultimate strength  lower than that of amalgam  Absorption of water  generation of internal stresses  Early composites  polymerization shrinkage and contraction away from the tooth structure marginal core and tooth opening, micro cracks and micro leakage  Micro leakage is not entirely eliminated even by new bonding agents.
  19. 19. Indications  As with all buildup materials more than 2 mm of sound tooth structure should remain at the margin for optimum composite resin core function.  On anterior teeth where a crown is not required and enamel margins provide long-term resistance to leakage  On posterior teeth where composite is used as a build-up material, maintaining at least 2 mm between crown margins and the build-up should reduce leakage.
  20. 20.  Richard W.Chan et al (JPD 1982;48:401) Cast-gold post-core combination and amalgam or composite resin cores used in combination with cemented steel post have been examined. Cast gold specimens required less force before failure occurred. All of the cast post core foundations showed displacement from original cemented position and most teeth showed evidence of root fracture. Amalgam and composite resin specimens commonly exhibited fracture of the core but showed less evidence of post core dislodgement and root fracture
  21. 21. R.A. Oliva et al (JPD 1987;57: 554) Did a study to investigate the dimensional stability of silver amalgam and a conventional composite used as core material. Result of this study indicates that silver amalgam used as a core material is dimensionally stable when exposed to moisture. Seating of crowns fabricated for silver amalgam cores was not affected by exposing
  22. 22. Conventional composite used a core material in this study was found to be dimensionally unstable when directly exposed to moisture. Seating of crowns fabricated to fit the composite cores was significantly affected by the dimensional instability of the resin core material
  23. 23. Glass Ionomer Cement Advantages  The major benefit  anticariogenic quality resulting from the presence of fluoride in the chemical composition,  Offer a low level of leakage
  24. 24. Disadvantages  Low strength and frac-ture toughness results in brittleness contraindicated as buildup material in thin anterior teeth or to replace unsupported cusps. Use limited to small restorations in which core strength is not required.  Glass ionomer cores exhibit low retention to preformed metal dowels.  Soluble and sensitive to moisture  Glass ionomer is not strong enough for a core for an abutment tooth.
  25. 25. It is indicated in posterior teeth in which (1) a bulk of core material is possible, (2)Sig-nificant sound dentin remains, (3) moisture con-trol is assured, (4) caries control is indicated.
  26. 26. Kovarik et al (JADA 2000) fatiguetested crowns with amalgam, composite and glass ionomer cores, and found that amalgam was significantly stronger than composite and that glass ionomer had inadequate strength as a core buildup.
  27. 27. Resin-modified glass ionomer Are a combination of glass ionomer and composite resin technologies exhibit properties of both materials. Exhibits moderate strength greater than glass ionomer and less than composite resin. As a core material it is adequate for moderate-size buildups. Hygroscopic expan-sion can cause fracture of ceramic crowns.
  28. 28.  Solubility is between that of glass ionomer and composite resin.  Fluoride release is equal to glass ionomer  The bond to dentin is close to that of dentin-bonded composite resin, and it is significantly higher than traditional glass ionomer.  minimal microleakage.
  29. 29. Advantages of direct core (Plastic Filling) Materials.  Maximum tooth structure can be conserved because undercuts do not need to be removed.  Treatment  There • • • requires less patient visit. are fewer laboratory procedures. Disadvantages Long-term success may be affected by  corrosion of amalgam cores, the low strength of glass ionomer, continued polymerization and high coefficient of thermal expansion and Microleakage of composites
  30. 30. CORONAL COVERAGE  Reestablish function  Isolate dentine and endodontic filling materials from microleakage  Protect tooth against fracture
  31. 31. Anterior teeth Intact, nonvital, anterior teeth minimal risk for fracture. Restorative treatment sealing of the access cavity.
  32. 32. significant loss of tooth structure crown supported and retained by the dowel and core.
  33. 33. Posterior teeth •Subjected to greater loading than anterior •More susceptible to fracture
  34. 34. Should receive cuspal coverage to prevent fracture
  35. 35. Procedure for tooth preparation
  36. 36. a) Removal of endodontic filling material b) Post space preparation c) Preparation of coronal tooth structure
  37. 37. a) Removal of endodontic filling material
  38. 38. Obturation performed with silver cones Retreatment
  39. 39.  The amount of gutta percha to be removed is dictated by:  The desired dowel length  The bone height.  The root morphology
  40. 40.  First completely obturate the root canal and then remove GPlateral canals will be sealed.  The removal of gutta percha can been done using Chemical: involves dissolving the gutta percha by chemical solvents such as xylene, chloroform. Mechanical: use of a heated plugger, rotary instruments like paezo reamers and gates glidden drills.
  41. 41. James E Haddex et al ( JPD 1990;64: 515-519) did a study to investigate the effect of the method of Guttapercha removal on apical seal. They concluded that heated pluggers should be used to remove guttapercha. Although rotary instruments remove guttapercha faster, they seem to disturb apical seal to a greater extent.
  42. 42. Gordon D. Mattison et al (JPD 1984;51:785) Did a study to analyze the apical leakage and effect of gutta-percha removal technique (hot instrument, mechanical rotary instrument and chemical solvent) on apical seal. They concluded that mechanical method is most desirable for gutta-percha removal in post preparation.
  43. 43. Before removing GP calculate appropriate length of post ( make it equal to crown Or 2/3rd of root, leave 5mm GP)
  44. 44. GP be removed immediately after obturation warm plugger (not with rotary instruments may disturb seal), instrument be hot enough to cut and remove the gutta percha. An instrument that is too cool melts the filling in a sticky mass that can dislodge the entire canal fill when the instrument is withdrawn.  Advantage allows operator to work in an area where root canal anatomy is still familiar.
  45. 45.  If old GP and has lost its thermoplasticity use rotary instruments Use safe tip instruments(pesoreamer). Friction generated between the RC material and insturment softens GPallows rotary instrument to track the canal with reasonable predictability. Donot use end cutting instruments(para post drill etc) to gain lengthmay cause root perforation.
  46. 46. use of chemical for gutta percha removal should be discouraged. The result of chemical removal may be leakage into root canal complex or into apical areas
  47. 47. b) Post space preparation Depend on type of post used. a) pre fabricated post  Enlarge canal using endodontic files, reamer or twist drills of same dimension as that of post (each system comes with its own standardized twist drills)
  48. 48.  Twist drills  to parallel the walls of post space  Careful not to remove excess dentine at apical extent of post pace  Threaded post appropriate drill followed by a tap that prethreads the internal walls of the post space.
  49. 49.  b) custom made post Not much of preparation required  enlarge enough so that post has adequate strength . Do not over enlarge weak walls (1/3rd)  Remove any undercuts present within the canal.
  50. 50. c) Preparation of coronal tooth structure  Ignore any missing tooth structure and prepare remaining tooth structure as though it were undamaged.  Remove external and internal undercuts.that will prevent withdrawal of pattern  Remaining wall thin (since tooth str. Removed from out and inside), ideally residual coronal wall be 1mm wide. 1 mm
  51. 51. Wall height reduce proportionately acc to wall thickness. (thin tall wall tend to fracture during removal of provisional restoration) (2mm) Prepare part of remaining tooth str. Perpendicular to post provide positive stop to prevent overseating and splitting of tooth. Provide ferrule effect to prevent fracture of tooth
  52. 52. Prevent rotation by making flat parallel plane . Sufficient tooth structure Present vertical coronal wall prevents rotation
  53. 53. Coronal dentine lost small groove ( anti rotational element)
  54. 54. fabrication of Custom made post
  55. 55.  Direct technique  Indirect technique  Direct technique recommended for single canals  Indirect technique more appropriate for multiple canals
  56. 56. Direct technique Materials  Inlay wax  Thermoplastic resin  Autopolymerising resin  light polymerised resin
  57. 57. Using auto polymerising resin Lubricate canal Select a loose fitting plastic dowel. Should extend to full depth of prepared canal Notch it 1. add resin only to canal orifice first Add resin on post using bead-brush Technique Or Mix some rein  roll in cylinder shape introuced in canal  Push with monomer moistened dowel.
  58. 58. Donot allow resin to harden fully Loosen and reset it several times Once polymerised remove it 2. Form apical part of post by adding additional resin  reseat and removing Care not to lock it in canal
  59. 59. add additional resin for core formation Slightly overbuild the core and let it polymerize Shape the core with carbide finishing burs.
  60. 60. 2.Rosenstiel et al (JPD 1997;77;209) Using thermoplastic resin material Palstic 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
  61. 61.  Lubricate canal  Heat thermoplastic material  Apply on apical aspect of rod
  62. 62. Insert the rod Wait for 5-10 secs reseat Inspect for completeness
  63. 63. Core build up from autopolymerising resin Trimmed to ideal tooth preparation form Final preparation.
  64. 64. 3. William H. Silverstein (JPD1964;14;374)  First prepare tooth for crown  prepare temporary acrylic resin crown  Prepare tooth for post and core casting
  65. 65. Fabricate direct wax pattern with aid of temporary resin crown.
  66. 66. Same procedure for posterior teeth 1 post in major canal and bead of wax in smaller canal
  67. 67. 4. Light cure resin (JPD 1992) (GC unifast LC ) Serrated plastic dowel (dura lay plastic pins)
  68. 68. Resin injected Plastic dowel placed
  69. 69. Curing coronal portion Curing apical portion
  70. 70. Core build up with resin Final resin pattern
  71. 71. Indirect procedure Orthodontic wire bend in J shape Verify fit loosely fit, extend to full depth If too tight impression will tear away
  72. 72.  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
  73. 73. Remove impression Pour cast
  74. 74.  In lab, select a plastic post (toothpick)  Using impression as guide make sure it extend to full depth
  75. 75. Lubricate stone cast Add inlay wax in increments on post Pattern fabricated
  76. 76. Add wax core and shape it
  77. 77. (J Prosthet Dent 2002;88:555-7.)
  78. 78. Vinyl polysiloxane material seated over prepared teeth on stone cast. teeth prepared for custom-cast posts
  79. 79. Plastic posts fitted and coated with autopolymerizing acrylic resin. Posts and cores immediately after removal of index material
  80. 80. Refined posts and cores
  81. 81. Direct technique for posterior Shillingburg et al (JPD 1970) Plastic tooth pick-loose First mix of acrylic resin ills the canal and completely covers the occlusal surface
  82. 82. Second mix of resin for completion of core preparation Finished pattern
  83. 83. 2. Single piece core with auxiliary post Indirect approach better as access is better Fit prefabricated post into prepared canal Roughen one post, others smooth and lubricate All posts should extend beyond eventual preparation.
  84. 84. Build core with autopolymerising resin Shape it Grip smooth posts with forceps and remove Remove pattern invest
  85. 85. Indirect pattern for multirooted teeth (split core) Wax the custom made post Build up part of core around first post
  86. 86. Remove any undercuts adjacent to other post holes Cast it Wax additional sections Cast them
  87. 87. Interlocking sections can be made using dove tails Complicated Limited benefit as final build up is held together by fixed cast restoration.
  88. 88. Provisional restoration  To prevent drifting of opposing teeth or adjacent teeth provisional restoration.  If cast post-core is made additional provisional restoration needed. Retained by fitting a wire into prepared canal.
  89. 89. By lining a polycarbonate crown. Not necessary that reline material may extend down till full length of post By engaging apical portion wire will enhance resistance of restoration.
  90. 90. Removal of existing post
  91. 91.  If sufficient length exposed coronally thin beaked forceps  Vibrating with ultra sonic scaler weaken cement facilitates removal  Ultrasonic cracks in dentine
  92. 92.  Post puller Vise to grip post Legs that bear on root surface Screw activates the vise and extracts the post.
  93. 93.  Using high speed bur  Fractured post can not be pulled by post puller or tweezer  Risk of cutting dentine
  94. 94.  Masserann technique for removal of fractured posts.  Diameter of post is gauged with sizing tool  Selected trephine is rotated counterclockwise to create a narrow channel around the post  Once sufficient material removed  Post recovered.
  95. 95.  Thomas post removing system High speed bur used to free the post from the coronal tooth structure and parallel its sides.
  96. 96. A trephine bur machines the post to correct diameter and places threads for the mandrel
  97. 97. Mandrel threaded on to the post which distribute forces evenly over the root
  98. 98. Beaks of plier fitted on to mandrel Screw rotated Beaks separated Post removed
  99. 99.  Removal kits for fiber post
  100. 100. Post placement and core build up Steps for luscent anchor system
  101. 101. Gutta-percha removed The length of the post determined in the canal
  102. 102. The trimmed post replaced canal etched with 37% phosphoric acid.
  103. 103. etchant gently rinsed with water and dried with paper points An adhesive primer and bonding agent applied
  104. 104. A flowable composite resin The flowable composite (Tetric Flow Ivoclar Vivadent, resin light cured ) dispensed for 60 seconds into the canal.
  105. 105. completed core build-up The core build up
  106. 106. Postoperative radiograph Final restoration
  107. 107. Bleaching as an treatment option
  108. 108.
  109. 109. Warren et al (J Endod 1990:16;570) Discoloration in the absence of significant tooth loss may be more effectively treated by bleaching than by placing complete crown.
  110. 110. Thermocatalytic Walking bleaching bleach
  111. 111. Thermocatalytic bleaching/ heat and light bleaching  A) cotton mat saturated with Superoxol (30%hydrogen peroxide) on labial surface and in pulp chamber Repeated several times On completion, cotton pellet moistened with superoxol or sodium perborate is sealed in pulp chamber till next appointment.
  112. 112.  B) alternative procedure  Activate supeoxol by using Stainless stel instrument heated over flame.
  113. 113. Walking bleach  Apply petroleum jelly on gingival tissues  Re-establish the access cavity  Remove GP till crest of alveolar ridge (1-3 mm below the free gingival margin  Seal root canal orifice with cement  Remove smear layer by applying 25%citric acid or 30% phosphoric acid
  114. 114.  Mix superoxol and sodiumperborate  Place in pulp chamber  Cover with cotton moistened with superoxol  Seal  Pt cavity with temp. cement recalled after 3-7 days.
  115. 115. Summary An endodontically treated tooth should have good prognosis. It can resume full function and serve satisfactorily as an abutment for fixed or removable partial denture Different clinical procedures have been advocated, many of which are successful if properly used. Where the crown is preserved, an anterior tooth can be safety restored with a plastic filling. To prevent fracture of posterior teeth, cast restorations providing cuspal coverage are recommended.
  116. 116. Preserving as much tooth structure as possible is important, particularly within the root canal, where the amount of remaining dentin may be difficult to assess. A post-and-core is used to provide retention and support for a cast restoration. It should be of adequate length for good stress distribution but not so long as to jeopardize the apical seal. The safest method to create post space is to use a warmed endodontic plugger to remove the gutta-percha.
  117. 117. Anterior tooth, particularly those with flared or elliptical canals, should be built up with a custom cast post-and-core, although prefabricated posts can be used successfully too. Esthetic post materials should be considered if a dark post would ruin an esthetic restoration. Amalgam can be used satisfactorily on posterior teeth, although a casting may be preferred if much coronal tooth structure is missing.
  118. 118. Conclusion Endodontically treated teeth have been exposed to a variety of insults ranging from caries, the operative procedures that follow, the chemical insults due to the restorative materials, loss of structural integrity (removal of critical dentin during endodontic procedures) and finally dehydration of the tooth structure.
  119. 119. Restoring such a tooth involves a range of treatment options of varying complexity. The loss of tooth structure makes retention of the subsequent restoration more problematic and increases the likelihood of fracture during function. If the requirements of the tooth are assessed carefully and the treatment is planned appropriately, it can resume full function and serve satisfactorily as an abutment for a fixed or removable partial denture.
  120. 120. References
  121. 121. 1 A simplified method of making post and cores (JPD 1970;24:287)  2 Restoration of endodontically treated posterior teeth (JPD 1970;24:401)  3 Evaluation and restoration of endodontically treated posterior teeth (JADA 1976;93:597)  4 Construction of a post and core to fit a completed restoration (JPD 1977;38:229)
  122. 122. 5 Preparation of endodontically treated teeth to receive a post core restoration (JPD 1977;38:413)  6 Factors influencing the retention of dowels (JPD 1977;38:515)  7 An amalgam coronal-radicular dowel and core technique for endodontically treated posterior teeth (JPD 1980;43:511)  8 The retentive and stress distributing properties of a threaded endodontic dowel (JPD 1980;44:398)
  123. 123. 9 Post core foundations for endodontically treated posterior teeth (JPD 1982;48:401)  10 Clinically significant factors in dowel design (JPD 1984;52:28)  11 Intracoronal reinforcement and coronal coverage: a study of endodontically treated teeth (JPD 1984;51:780)  12 Effect of post preparation on the apical seal (JPD 1984;51:785)  13 Endodontically treated teeth as abutments (JPD 1985;53:631)  14 Dimensional stability of silver amalgam and composite used as core materials (JPD 1987;57:554)
  124. 124.  15 Retention of cast endodontic posts:comparison of cementing agents (JPD 1988;59:318)  16 Ferrule design and fracture resistance of endodontically treated teeth (JPD 1990;63:529)  17 Threaded endodontic dowels :effect of post design on incidence of root fracture (JPD 1991;65:179)  18 An accelerated technique for casting post and core restorations (JPD 1991;66:155)
  125. 125.  19 In vitro bond strength of silica coated metal posts in roots of teeth (IJP 1992;5:373)  20 Evaluation of fracture resistance of a wrought post compared with a completely cast post and core (JPD 1992;68:443)  21 Effect of eugenol containing endodontic sealer on retention of prefabricated post luted with an adhesive composite resin cement (QI 1992;23:839)  22 The dentin root complex:anatomic and biologic considerations in restoring endodontically treated teeth (JPD 1992;67:458)
  126. 126.  23 Light cured resin for post patterns (JPD 1992;68:412)  24 Root fracture in endodontically treated teeth related to post selection and crown design (JPD1992;68:428)  25 Retention of posts cemented with various dentinal bonding cements (JPD 1994;72:591)  26 Custom cast post fabrication with a thermoplastic material (JPD 1997;77:209)  27 Comparison of the fracture resistance of pulpless teeth restored with a cast post and core or carbon fibre post with a composite core (JPD 1998;80:527)
  127. 127.       28 An in vitro study of the fracture resistance and incidence of vertical root fracture of pulpless teeth restored with six post and core systems (JPD 1999;81:262) 29 Essential endodontology – D. Orstavik and T.R.Pittford 30 Contemporary fixed prosthodontics 3rd edn – Rosenstiel, Land, Fujimoto 31 Pathways of the Pulp 8th edn. – Stephen Cohen, Richard C. Burns 32 Color atlas and text book of endodontics 2nd edn – Christopher J. 33 Preservation and restoration of tooth structure – Graham J.Mount
  128. 128.
  129. 129. The Ruddle post removal system including the extractor. (B) A domer bur, trepan and tap used to modify and engage the post. Ruddle post removal system (Fig. 8.4) which consists of a series of trepans to mill the post, tubular taps to engage the post and extraction pliers to provide the elevation force.
  130. 130. (A) Masserann kit. (B) Close-up of a Masserann trepan.
  131. 131.                     The Masserann system is preferred to the Ruddle for removal of fractured posts, as the metal trepans are thinner and therefore more conservative of tooth tissue. A suitably sized trepan is directed along the side of the post in the space created by the ultrasonic tips. A smaller trepan may then be used to grip and remove the fractured portion (additional ultrasonic vibration applied to the trepan may be useful at this point). If the post is of the screwin type, then it may be unscrewed after the use of ultrasound to weaken the cement seal, either by placing a groove in its end or grasping it with a tight-fitting trepan. If this is unsuccessful, then a trepan should be selected which will cut along the threads of the post, as this will minimize the amount of dentine removed while easing the cutting of the metal. In exceptional cases, fractured posts may be drilled out using an endcutting bur. This procedure, however, is rarely necessary in view of the recent developments in ultrasonic tip design and improved magnification and lighting.
  132. 132.  Vented post
  133. 133.
  134. 134.
  135. 135.
  136. 136. Thank you Leader in continuing dental education