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Post endodontic restoration /certified fixed orthodontic courses by Indian dental academy


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Post endodontic restoration /certified fixed orthodontic courses by Indian dental academy

  1. 1. Post Endodontic Restorations INDIAN DENTAL ACADEMY Leader in Continuing Dental Education
  2. 2. INTRODUCTIONThe goal of the endodontic restoration is toprovide optimal oral health, esthetics andfunction.Therapeutic efforts made to result in easilymaintainable and reliable treatment over longterm.Endodontic therapy, restorative dentistry andperiodontal health are intimately related.The purpose of this topic is to discuss thiscomplex relationship, treatment planning andprocedures for restoring these RC treated teeth.
  3. 3. HISTORY• 1747 PIERRE FAUCHARD described how to restore roots of pulp less teeth --- PIVOT today termed as a post (Made of gold or silver) ---Mastic-heat softened adhesive (mastic) (prepared by Gum, Lac, Turpentine and White coral powder)• 1849 Sir John Tomes Post length and diameter confirmed closely to today’s principles in fabricating posts.• 1869 G.V Black advised filling the gold foil.• 1878 Richmond Crown – porcelain faced dowel crowns• 1880 U.S Seasoned wood as a pivot• 1960 Carbon fiber post• 1989 Modifications of Carbon fiber posts• 1996 Meyeberg – Zirconium posts• 2000 Everstick & Millinium white post
  4. 4. DefinitionsPost (dowel):- Refers to a cylindrical ortapered object that fits into the preparedroot canal of a toothCore :- Refers to a build up restoration ,usually amalgam/composite placed in abadly broken down tooth to restore thebulk of the coronal portion of the tooth tofacilitate subsequent restoration by meansof an indirect extracoronal restoration
  5. 5. Changes in teeth after RCT• Loss of tooth structure• Absence of pulp• Decrease in moisture content• Physical properties (strength)• Esthetics• Nature of dentine toughness• Collagen fibers alignment
  6. 6. When the Post Is Indicated Depends on how much tooth structure remains after RCT to retain core material As an abutment• Tooth which is susceptible to # Incisors – JC or post is not indicated (only depends on amount of tooth structure remains and Esthetics) Premolars require post more often than Molars -- Small pulp chamber -- Less tooth structure -- Inclined lingually So restoring the RCT teeth with Amalgam/ composite/miraclemix will strengthen the tooth but may #
  7. 7. Placement of crown on an endodontically treated tooth reduced its Fracture only by 2% -- for anterior teeth And 38% to 48% # for posterior teeth when left uncovered (sorensen and Martinoff) MOD preparation reduces stiffness by 63% Molar teeth # at 122 Kg (left uncovered after RCT and MOD) and teeth # at 341 Kg (when the crown given) Occlusal cavity reduced cuspal stiffness by 20%
  8. 8. WHY THE POST IS NEEDED?• To give support for the core material• To replace the lost crown structure PRE TREATMENT EVALUATION• Endodontic evaluation• Periodontal evaluation• Restorative evaluation• Esthetic evaluation
  9. 9. Factors which are not favorable For post endo Rx: Severe curvature of root - eg:- dilaceration of root• Perforations caused by resorption• Poor crown to root ratio , vertical #• Sensitivity, inflammation, sinus opening, exudate , apical seal, and peridontitis
  10. 10. Fundamental rules for “post”• The post must be at least as long as the crown• The post must have parallel sides or have a max convergence of 3-5 °• The post must achieve a precision fit in the canal.
  11. 11. Basic components used in restoration of Non vital teeth Dowel Core material Coronal restoration
  12. 12. How much GP should be removed to preserve apical seal• Portell :- Tested leakage around 3,5,7 mm GP – -leakage around only 3mm of GP left• Nixon et al:-compared leakage around 3,4,5,6,7mm GP left by DIE INK PENETRATION TEST and found greatest leakage around 3 mm and least around 6mm• Kvist et al found more periapical radiolucencies found around 3mm GP left• So 4-5mm www.indiandentalacademy.comgood apical seal GP should be left for
  13. 13. When to remove GP?• No difference between immediate and after 1 week -- ( Bourgeois and lemon ) NO difference between 5 mins and 48 hours (BY DIE INK PENETARTION METHOD)— ZMENER• Significant difference between immediate and after 24 hours --DICKEY et al• So adequately condensed GP can be safely removed immediately after obturation
  14. 14. What instruments remove GP without disturbing apical seal?• No difference in leakage between removing GP with hot instruments (i.e. pluggers) and rotary instruments (i.e. gates glidden and peeso reamers)• Less leakage when hot instruments are used --HADDIX et al
  15. 15. How to Remove GP• By chemical solvents (xylol, chloroform and eucalyptol)• Mechanically (by gates glidden and peeso reamer)• Thermally (by hot pluggers)• Combination with one another• Its shown that after GP removal vertical condensation improves the apical seal
  16. 16. Dowel (Post)• It is the metal post or rigid restorative material placed in the radicular portion of non vital teeth Functions: To retain a core material• For the distribution of masticatory forces to the root• To decrease the risk of root fracture
  17. 17. Classification of postsBroadly categorized into Custom cast posts and• Preformed post systems Tapered Smooth Serrated parallel threaded
  18. 18. Based on materialMetallic posts Non metallic posts Dentatus post Carbon post Para post Aestheti plus post Root post FRC post Zirconium oxide post Ceramic post
  19. 19. Resistance triad• Anti rotation• Vertical remaining coronal tooth structure• Crown bevel RETENTION TRIAD Post length Post shape Luting cement used
  20. 20. Factors effecting retention & resistance form• Post length• Post design• Post diameter and remaining dentin• Surface preparation• Canal preparation• Cement used• Anti rotational groove
  21. 21. Post length• Equal to Inciso cervical or occlusocervical dimension• Should be longer than crown• Half the root length• Two thirds of root length• Halfway between crestal bone and root apex• Should be as long as possible without disturbing the apical seal• At least 3 Quarters of post length (leary et al 1987 JOP)• For molars should not be extended more than 7 mm (palatal for Maxillary and distal for Mandibular)
  22. 22. Post diameter• As the post diameter increases-increase in retention (shillingburg, turner)• No significant retention changes with diameter variation (standlee JP, kurer)• As the diameter increased there is increase in stresses in the tooth• Increased diameter decreases the tooth resistance to #• 1 MM the tooth diameter decreases—six times the # potential increases• Large diameter posts showed higher root #• POST DIAMETER SHOULD NOT INCREASE ONE THIRD OF ROOT DIAMETER (Goodacre 1995 JOP)
  23. 23. Post
  24. 24. Relation between post diameter and the potential for root #• Post diameter should not exceed 1/3 rd of root diameter• Mand. incisors 0.6-0.7 mm• Max. central incisors 1.7 mm• other teeth 0.8-0.9 mm Mesial roots of Max. molars and Buccal roots of Mand. molars should not be used for custom posts
  25. 25. Post shapeTapered form Less tooth structure is removed• Act like wedge - exert lateral forces - vertical root fracture• Used in tapered root canalsParallel sided• More tooth structure is removed• More retention & decreases force distribution.• 2-4 times more retentive than tapered posts.
  26. 26. Surface of the postSMOOTH SURFACE• Least retentiveSERRATED SURFACE• More retentive than smooth surfaced• Provide mechanical undercuts for cement .• Serrations can be Horizontal with single vertical vent channelThreaded• Most retentive• Significant stress
  27. 27. • Tapered posts produced the greatest stress at the coronal shoulder, and parallel posts generate their greatest stress at apex of the canal preparation (Oral Sci Rev 1977)• Parallel posts resisted tensile, shear and torquing forces better than tapered and distribute stress more uniformly along their length during function (JOE 1991)
  28. 28. FEA & PHOTOELASTIC studies:
  29. 29. Does the surface and shape of the post influence the root #• Tapered Threaded posts produce greatest stress and highest potential for root # (7%)• Tapered threaded posts increases root # by 20 times that of parallel threaded posts (parallel sided posts distribute stress more evenly to the root )• Tapered cemented posts (3% root #),and parallel cemented posts (1% root #)• Split threaded posts produced less stresses than than threaded posts
  30. 30. Cementation• Glass ionomer cement• Zinc phosphate cement• Polycarboxylate cement• Resin cement• Cast gold luted with ZnP bond failed at 11897 cycles ParaPost (Ti alloy) luted with Znp and Comp. core bond failed at 24384 cycles FiberPost luted with resin cement and Comp core bond failed at 50,696 Cycles ( JOP 2005) Film thickness :- Thicker layer of cement will transform stresses to the tooth in a Different manner than a Uniform Thin layer of cement (JOE 1990)
  31. 31. • Occlusal force micromovemants Disintegration of brittle cement Conc. of stresses at Apex # of Root ANTI ROTATIONAL GROOVE
  32. 32. Technique of cementation:- Application of cement in the canal (with lentulospiral) is essential because it produces Uniform, Bubble-free layer of cement and voids that Distributes stresses Evenly (OOO 1972)(1). Post space should be free of residue [ Residue in the canal can generate enough force to cause root #] ( JOP 1993 )(2). Hydrostatic pressure in the cement , excessive seating pressure and the torque exerted by the clinician may cause # of Root (J D RESEARCH 1985)(3). Post space should be cleaned by a 17% EDTA (30 sec),5.2% Naocl(30 sec) ,Rinse with H2O and Dried paper points. (J D RESEARCH 1984)
  33. 33. Core• Replaces carious, missing or # tooth structure• It is anchored to the tooth by the direct connection into canal or to the post• Tooth structure can also be altered to enhance retention, resistance and to prevent rotation (pins, grooves and channels)
  34. 34. Ideal requirements of core material:- Morgano and brackett described as Adequate compressive strength Sufficient flexural strength Biocompatible Resistance to leakage Ease of manipulation Bonding to tooth structure C.E.O. thermal Exp Dimensional stability Min potential to H2O ABSORPTION of dental caries
  35. 35. CAST CORE• It is the one piece dowel and core in a traditional and proven method for restoring endodontically treated teeth• This has superior physical and mechanical properties at the• Dowel & core junction• Main disadvantage is NO of appointments and Lab. procedure
  36. 36. Post material• Alloys of gold ,SS, titanium ,Ni-Cr, Ceramic posts, FRC, and dental amalgam• Wrought gold alloy posts are 2-4 times stronger than cast gold alloysMaterial should be:-• Adequately stiff and high yield strength (resistance to permanent deformation)• Resistance to corrosive effect of oral fluids
  37. 37. • Success rate of 90.6% using cast post and core as a foundation material• Cast gold alloy type 3 and 4 as an inert material with 6 M.O.E (stiffness of 14.5 x 10 ) 6 C.E.T.E is =15 x 10 similar to those of Enamel Main disadvantage is Esthetics Metal ceramic crown is given to mask the shade of the metal
  38. 38. How post metal corrode(1). Initiation of corrosion is by access of electrolytes via cementum dentine covering root surface(2). Microleakage around post and core(3). # of root during post space preparation Corrosion of posts is mainly because of presence of Zn and Cu in posts (Derand et al) Base metal is most corrosive Ti posts most corrosive resistant- passivation
  39. 39. • Nayyar amalgam core• SECTIONED Nayyar amalgam core
  40. 40. COMPOSITE RESIN CORE Advantages• Less time consuming and ease of manipulation• Additional retention and anti rotation features easily achieved Disadvantages• Polymerization shrinkage & contraction- marginal discrepancy• At least 2mm coronal tooth structure - for build up• Retention of core with zirconium posts ?• Microleakage• Sensitivity
  41. 41. GIC core• Is indicated when there is significant amount of dentin is remaining and an additional retention is needed• Main advantage is the anticariogenic potential• Main disadvantage is high solubility moisture sensitivity• Low retention to preformed dowels• Low strength and fracture toughness• Technique sensitivity
  42. 42. Resin modified GIC core• Improved properties than conventional GIC core• Bond strength close to that of bonded composite restoration Microleakage less than GIC 88% of tooth stiffness is recovered after restoring the ET tooth with composite (JADA 2005)Disadvantage:• Dimensional instability in the presence of and leads to expansion
  43. 43. Diaphragm• Diaphragm or apron, usually placed on palatal aspect• May help to brace the tooth and distribute forces more favorably• It prevents conc. of stresses around the apical portion and leads to decrease in horizontal or oblique #
  44. 44. FerruleFerrule = ferrum (iron) + vairiola (bracelets)It is a metal band that encircles the externalsurface of residual tooth• Resistance form primarily , and retention also• It resists the lateral forces and leverage action• Reduces the incidence of #• To be effective - it must encircle the tooth(360) °
  45. 45. • Ferrule width is more imp than post length in increasing the tooth resistance to #• Bevelld or sloping ferrule is effective• Ferrule created by crown encompassing the tooth structure is more effective• Circumferential contra bevel reinforces the coronal aspect• Positive occlusal seat - acts as a anti rotational device• Without ferrule tooth # at 49.6 kg force applied at 135° and with ferrule of 2mm # at 65.29kg (JOP 1989)
  46. 46. Types of ferrule• Core ferrule• Crown ferrule• Crown ferrule is more effective than core ferrule what should be the width of ferrule?• 1.5-2.0 mm ferrule of crown more effectively enhances # resistance of custom cast post and core• Ferrule which covers -larger amounts of tooth structure > than small amount of tooth structure• Presence of 0.5-1mm of ferrule is ineffective
  47. 47. • Tooth restored with PFM # at 958 N (without post) No ferrule / cast post and core / PFM # at 992 N 2mm ferrule / pre fabricated post and resin core / PFM # at 994 N 2 mm ferrule/cast post and core # at 1793 N (JOP 2003) Crowns alter the distribution of forces i.e restoration should have subgingival collar, which acts by its “hugging” action and prevents vertical # of the tooth
  48. 48. Principles of tooth preparation(a) CONSERVATIONISTS – Restrict the diameter of the post (Mattison)(b) PROPORTIONISTS – Diameter should not exceed one third of root diameter (Stern and Hirshfled, Tilk et al)(c) PRESERVATIONISTS – 1mm of sound dentin surrounding the entire canal (Halle et al)
  49. 49. The crown and crown prepn. Should be• Parallel axial wall• Min of 1-2 mm dentine axial wall• Margins should be on sound tooth structure• It must not invade the attachment apparatusResistance form:-• Post design should distribute stresses as evenly as possible to prevent #• Residual tooth b/w core and gingival sulcus must be structurally sound and min. of 2mm high for the crown ferrule and margin
  50. 50. • If there is insufficient tooth structure to construct ferrule – periodontal crown lengthening surgery or orthodontic extrusion is indicated• Gingivectomy
  51. 51. Retention form• It is the Dislodgement of post retained anterior crown• It is due to inadequate retention form of the prepared post Retention of the post is mainly affected by• Post length• Post diameter• Surface texture
  52. 52. CUSTOM CAST POST AND CORE• In direct technique using inlay wax, auto polymerizing or light polymerizing resin usually for single tooth restoration• Indirect technique – multiple teeth or tooth with multiple canals• The post/pin should extend the full length of prepared canal• soft wax is added or a brush bead technique is used to add resin
  53. 53. Indirect tech. for the construction of multipost• Impression post canal rubber base of the tooth preforrmed posts impressionImpression of the die
  54. 54. • Wax pattern withdrawable post pattern posts in 2 canals try in• Removable post & core post-op Posts inserted cemented
  55. 55. Restoration of teeth with resected root• Tooth pre post resection resectionWax pattern cast post luted post op
  56. 56. Restoration of a hemisected tooth• Difficulties of contouring rest. in furcation
  57. 57. PROVISIONAL RESTRORATIONS It plays an important role in the successful restoration of a toothFUNCTIONS• Esthetics• Protection of the tooth from further damage• Prevents migration of adjacent teeth• provides occlusal function• Poly carbonate crowns• Plastic posts relined with acrylic resin• Silicone post reinforced with a paper clip or orthodontic wire• Braided SS wire with acrylic resin crown• SS crowns with reinforcement
  58. 58. Pre fabricated posts• Wide range of prefabricated posts are available in various shapes and sizes• Parallel sided prefabricated posts are recommended for conservatively prepared root canals with Circular cross section.• Excessively prepared canals managed with custom post.
  59. 59. Recent advances in post systemFiber-reinforced resin post systems:-1) Carbon fiber post system2) Luscent anchor post system3) Twin luscent anchor post systems4) Double taper post system5) Luminex post technology6) Parapost fiber white system7) Anatomic post & core8) ceramic post & core system9) Ni-ti posts10) Flexi post11) Everstick post12) Millinium post
  60. 60. Fiber reinforced composite post system• The addition of fibers to a polymer matrix results in a significant improvement in the mechanical properties of :-• Strength• Fracture toughness• Stiffness• Fatigue resistance• The fibers composed of WOVEN POLYETHYLENE GLASS OR CARBON
  61. 61. ADVANTAGES:- Disadvantage• One appointment tech • Tech sensitive• No lab procedure • Need for an adhesive• No corrosion protocol• Root # is less• Conserved tooth structure• Improved Esthetics
  62. 62. • Fibers are 7 – 10 micro meters in diameter and are available in braided, woven and longitudinal configurations M.O.E is 1 and 4 x 10 6 psi which is closer to that of dentin =2 x 10 6 and this can psi decrease the incidence of root Fracture 95% of FRC posts showed the success rate And these can be easily removed in failure cases
  63. 63. Carbon fiber post system• Introduced in 1990 by DURET,REYNAUD & DURET• Fabricated from continuous unidirectional carbon fibers,8 micro meter in diameter and embedded in an epoxy matrix• The fibers constitute 64% of post weight• Modulus of elasticity is similar to dentine• Available in 3 diameters:1.4mm,1.8mm,2.1mm
  64. 64. Mechanical properties• Compressive strength 449 mpa• Shear strength 170 mpa• Tensile strength 1.6 mpa• Modulus of elasticity 8-110 Gpa• At 90 degrees angle to the post the MOE is 8 Gpa (that is equal to radicular dentine) Disadvantage:-• Not esthetic-causes black/grey shadow• The post is radiolucent
  65. 65. Luscent anchor post system• This is the one step effective procedure for curing composites within the confines of canals providing anchorage and esthetics• Transmits polymerizing light within confines of canals• Reflects natural hues for flawless aesthetics• Visible radiolucency in canal and through the core material• Available in 3 diameters to fit into very slim and large canals
  66. 66. Twin luscent anchors:-• This design gives visible assurance against accidental debonding of adhesive and resin core material• Slim mid section creates Physical choke• Vent grooves eliminates air resin entrapment and prevents rotational dislocation• Twice the retention
  67. 67. DOUBLE TAPER POST SYSTEM (DT postsystem)• This system provides close canal adaptation with mainimal tooth structure removal• Bigger taper at the coronal level so better adaptation and less polymerizing shrinkage DT quartz post
  68. 68.
  69. 69. Tran illuminating luminex post system• Used in thin walled roots• The clear light transmitting posts polymerize light-cured composites within the entire root canal• After curing LUMINEX post is removed leaving a ready canal for a post
  70. 70. Advantages• These will reinforce root strength• Improved control• Centered canal position• Superior esthetics• Technique versatility
  71. 71. DENTATUS CLASSIC POST SYATEM (FRC posts)• Made of polyethylene woven fibers that are treated with cold gas plasma hydrophobic to hydrophillic (this allows complete wetting and infusion of fibers by resin, creating lower contact angle and greater bonded surface area to enhance adhesion to rest. material)
  72. 72. ADVANTAGES DISADVANTAGES• Max. post retention • Need for careful and core stability adhesive protocol• Conservation of tooth • Need to demonstrate structure long term• Internal adaptation effectiveness• Esthetics • tech. sensitive• No corrosion• M.O.E ,flexural and T.S similar to root dentine
  73. 73. Ceramic postsAdvantage Disadvantage• Biocompatibility • Low # resistance• High flexural • Low # toughness strength(1400 Mpa) • Brittle• High strength and resilience• Esthetics• No corrosion
  74. 74. FILPOST• Made of titanium(99.8%)• Biologically inert, compatible with all dental materials• Fast and easy to place• Can be bent and shortened to customize• Minimizes potential of crown root #allows placement of 2 posts in molars
  75. 75. • Post can be adjusted i.e bent to the size and shape of the individual canal and cemented
  76. 76. World post supplied with primary reamer and secondary drill secondary drill- tier-stabilizes & bottoming out Length & head position Peeso Gates Primary reamer 1 2 0 3 4 1 4 5 2 5 6 3
  77. 77. Advantages :- Passive fit post Parallel sided and serrated for Max. retention It has counter sink to prevent wedging effect of post It has vent for escape of cement Easy to retrieve It can be bent Tensile strength is same as dentine Made Ti Al Vandium Does not corrode
  78. 78. ParaPost XP Is a parallel sided passive post.. 19mm length makes it ideal for elongated canals. Available in stainless steel or ti alloyParaPost XH Passive post with a rounded undercut, slotted head. Designed to lock on composite and glass ionomer Available in titanium alloy in seven sizes.ParaPost XT Requiring mechanical retention.Threads located in the coronal section of the post to provide extra retentionAvailable in titanium alloy.
  79. 79. FLEXI POST Parallel sided , threaded , splint shank Advantage :- Absorbs the stresses of insertion (closes during placement) Retention Twice retentive than para post Can be reduced 4 mm coronally Available in Flexi flange also
  80. 80. MAILLEFER RADIX ANKER LONG ( titanium alloy)
  81. 81. Gold coated anchorage postsDentatus
  82. 82. Sand blasted posts
  83. 83. C-post Millennium White Composition:• Glass fibres• Epoxy polymer• Disadvantages :• Less penetration of bonding resins when compared to Everstick Post
  84. 84. Everstick Post Composition :• Glass fibre• Polymethylmethacrylate• Bis-GMA• Advantages :• The degree of penetration of bonding resins is greater• This helps in establishing a good bonding between FRC posts , luting cements and composite cores.
  85. 85. Techs .of Post removal• Masserann tech• Post puller• Ultrasound• Ganon post removing system• S.S white post extraction kit• Fiber post removal kit• Diamond and Largo bur( is effective than post removal kit JOE 2003)
  86. 86. • Cutting the FRC post with carborundum disk showed regular surface than with scissors and with rotary instruments (which showed # lines along their length) SEM study JOE 2003• Application of adhesive solution in the canal is more effective with micro brushes than with small plastic brush (JOE 2002)• The highest resistance to post dislodgement is shown with taper of 0.04(i.e 79.10 lb) and lowest with taper of 0.02 (18.70 lb) JOE 2002• Metallic posts showed greater microleakage than non metallic posts (JOE 2002)• Decreasing proximal dentin thickness increased the tendency for buccolingual fracture (VRF) IEJ 2002
  87. 87. Basic principles to be followed for therestoration of endodontically treated teeth:- Provide cuspal coverage for posterior teeth-use post with adequate strength in thin diameters-provide adequate post length for retention.-Maximize resistance form including an adequateferrule
  88. 88. Common failuresTurner 1982 (Dental updates) ; a survey for 5 years showed :-Out of 100 post – retained failures 59 caused by post loosening apical lesions and caries next common 10 # roots 6 # postsSorenson & Mortinoff (JOP 1984)Out of 420 teeth – 36 post & core failures (8.8%) 13 post dislodgement 12 non restorable tooth # 8 restorable tooth # 3 perforations
  89. 89. CONCLUSION:-• The success of treatment depends on quality endodontic treatment, periodontal support available, shape of the canals, and the status of remaining tooth structure.
  90. 90.