Post endodontic restoration/ orthodontic continuing education


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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.

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  • Remainder flash is cut off by heavy carbide acrylic bur , and the restoration is polished with pumice and whiting, its seated with suitable temp. cement.
  • Post endodontic restoration/ orthodontic continuing education

    1. 1. POST ENDODONTIC RESTORATION INDIAN DENTAL ACADEMY Leader in continuing dental education
    2. 2. • CONTENTS 1. Introduction 2. History 3. Restorative decision making 4. Differences between Vital & Endodontically treated teeth 5. Stress distribution patterns 6. Fracture predisposing patterns 7. Restorative classification for endodontically treated teeth 8. Biomechanical Considerations 9. Treatment planning 10. Foundation Restoration 11. Principles of Tooth Preparation and procedures Post Core
    3. 3. 12. Temporization 13. Post fabrication 14. Cementation 15. Managing roots with open apex. 16. Root reinforcement 17. Conclusion 18. References
    4. 4.
    5. 5. The goal of Endodontic and Restorative dentistry is to retain natural teeth with maximum function and aesthetics So, for long term clinical success of the endodontically treated teeth requires skilled integration of restorative and endodontic disciplines.
    6. 6. HISTORY • 1728 – Pierre Fauchard described the use of “TENONS” which were metal posts screwed into the roots of teeth to retain the prosthesis • 1745 – Claude Mouton published his design of a gold crown with a gold post that was to be inserted into the root. • 1830-1870 –Wood replaced metal as the material of choice for posts. • 1871 – Harries introduced wooden posts. However, they swelled and caused roots fracture.
    7. 7. “Pivot crown” – a wooden post fitted to an artificial crown and to root canal • 1884 – Richmond crown • Later 19th century, single piece post crown. • 1930 – custom cast post and core replaced the one piece post crowns or the Richmond crown. • 1960’s – Prefabricated post – core systems introduced. • 1990’s (Shillinburg 1997) – Widely used prefabricated post – core systems.
    8. 8. Restorative Decision Making Anterior teeth:- Minimal to moderate Coronal damage:- Conservative treatment Resin composite, Reinforced GICs JPD 1984;51 Significant Coronal Damage:- Complete crown coverage Custom cast post and core; Prefabricated post and core
    9. 9. Posterior Teeth :- Cuspal coverage required Minimal damage:- Intact buccal/lingual walls; Minimal occlusal load Conservative Treatment:- MOD Onlay Classification of remaining tooth structure based on no. of existing axial walls: Navmann et al 2002 Class I :- - 4 remaining cavity walls - Thickness greater than 1mm No need for inserting posts Class II & III -Loss of one or two cavity walls -Remaining hard tissue capable of supporting core-Adhesive system -No indication of using a post Class IV -1 remaining cavity wall Post Indicated Class V -No remaining cavity wall Post Indicated; Ferrule effect is significant
    10. 10.
    11. 11. Fractures in endodontically treated teeth have been understood to be multifactorial in origin.
    12. 12.
    13. 13. Endodontically Treated Teeth 1. Loss of tooth structure. 2. Altered physical characteristics. 3. Altered esthetic characteristics. Loss of tooth structureLoss of tooth structure a)a) Endodontic access cavity destroys the strucutural integrity provided by the coronal dentinEndodontic access cavity destroys the strucutural integrity provided by the coronal dentin of the pulpal ceiling.of the pulpal ceiling. b.b. Tooth stiffness reduction by 5 %.Tooth stiffness reduction by 5 %.
    14. 14. Are endodontically treated teeth brittle? Vital dentin was 3.5% harder than dentin from contralateral endodontically treated teeth. JOE1992; 18(7): 332-335 Reeh et al stated that endodontic procedures reduced the relative cuspal stiffness of premolar teeth by only 5%, An occlusal cavity preparation (20%) and an MOD cavity preparations (63%). The concept of “brittle” or weakened endodontically treated teeth has been attributed to loss of tooth structure following trauma, caries, endodontic access, instrumentation. AlthoughAlthough Helfer et alHelfer et al reported 9% lower water content of pulpless teeth versus vital teeth.reported 9% lower water content of pulpless teeth versus vital teeth.
    15. 15. Altered physical characteristics a) Changes in collagen cross linking and dehydration of dentin. 14% reduction in strength and toughness. Altered esthetic characteristics Biochemically altered dentin modifies light refraction through the tooth and correspondingly modifies its appearance.
    16. 16. Restorative classification of endodontically treated teeth: CLASS • One canal • Two canals • Three canals Sub classification a) Chamber space:-Interlocking; limited interlocking, Non-interlocking b) Canal quality:-Shape: Segmented: straight/curved Uniform: straight/curved Size: Diameter: uniform/segmented Length: Short/normal/long Taper: Uniform: parallel/tapered segmented,parallel/tapered Journal of esthetic dentistry 1998; 10(2): 75-83
    17. 17. Biomechanical considerations in restoring Endodontically treated teeth Journal of Prosthetic Dentistry 1994; 71(6): 565-567 . Maximal force occurs at external surface of root and decrease to zero at the center of pulp space. Center of root is neutral area as regard to stress concentration. A post therefore receives minimal stresses under occlusal load and consequently does little to reinforce root under Stress distribution across root in tooth under load
    18. 18. The key differences between intact tooth and tooth restored using post–core are :- (1)Occurrence of regions of stress concentration. (2)Increase in the tensile stresses produced within the remaining tooth structure of a post–core restored tooth. (3) Increased flexure of the remaining reduced tooth structure.
    19. 19. The maximum shear stresses were primarily located at the post cement/dentine interface, while the maximum tensile and von Mises stresses were primarily located at the peripheral portions of the tooth. This tensile and von Mises stresses culminate in increased risk of root fracture, while the shear stresses culminate in increased risk of loss of retention of the post.
    20. 20. Treatment Planning A. Endodontic consideration: B. Restorative consideration C. Periodontal consideration
    21. 21. A. Endodontic consideration:  Dense, uniform, three dimensional obturation (fluid impervious seal) of the root canal system,0.5 to 1 mm from the radiographic apex of the root/roots is necessary.  Unsatisfactory obturation should be re-treated. B. Restorative consideration: • A critical amount of solid coronal dentin is required, which must encase a coronal restoration for structural integrity of the restored tooth. a) Dentin axial wall height- At least 2 to 3mm b) Axial walls must be parallel. c) Restoration should completely encircle the tooth . d) The margin should rest on sound tooth structure. e) The crown and the crown preparation should not invade attachment
    22. 22. Ferrule Effect:- (Eissman & Radke ) • A ferrule can be defined as a metal ring or cap put around the end of a tool to give added strength.(Webster’s New World Dictionalry Springfield 1968) • It is a 360 degree ring of cast metal extension at least 2mm apical to the junction of the core and the remaining tooth structure. • Ferrule created by the crown-encompassing tooth structure is more effective than a ferrule that is part of the post and core • Ferrule is desirable, but should not be provided at the expense of the remaining tooth/root structure. CORE FERRULECROWN
    23. 23.
    24. 24. C. Periodontal consideration: • Dimensions of the attachment apparatus range from 1.77 mm to 2.43 mm. This means that there should be an absolute minimum of 2.5 mm distance between the restoration margin and the crest of bone. • Biologic width relates the amount of tooth structure coronal to the osseous crest to the gingival attachment apparatus. • As a general rule, a minimum of 3 mm of sound tooth structure coronal to the osseous crest will be necessary to accommodate the connective tissue attachment, the junctional epithelium, and the margin of the crown. Defective tooth structure requiring margin placement in to zone B or C is is an indication for periodontal crown lengthening or orthodontic extrusion. (preferred)
    25. 25. Extrusion Distance = X+BW+1 X= Distance b/w alveolar crest and deepest extent of destruction BW= Biologicwidth=J.E(0.97mm)+C.T.A(1.07mm)
    26. 26. • Other Factors: a) Tooth type, morphology, arch position, the occlusal and prosthetic forces applied to the tooth and the amount of tooth substance loss. b) The translucency of all ceramic crowns must be considered in the selection of dowel and build up materials.
    27. 27. Restorative Treatment Planning Considerations:-  Amount of remaining tooth structure.  Anatomic position of the tooth.  The occlusal forces on the tooth.  Restorative requirements of the tooth.  The esthetic requirements of the tooth. Timing the Restorative Treatment  Good apical seal  No sensitivity to pressure  No exudate  No fistula  No apical sensitivity  No active inflammation
    28. 28. Restoration of non vital teeth Basic components:- Apical endodontic seal (5mm of Gutta-percha) Dowel Core Final coronal restoration
    29. 29. Foundation Restoration: Post and Core The post and core and their luting or bonding restoration together form a foundation restoration to support a coronal restoration for the endodontically treated teeth. JPD 82:643,1999 POST: The Post is a restorative dental material placed in the root of a structurally damaged tooth in which additional retention is necessary for the core and the coronal restoration. Functions:-  Retention of the core and crown.  Protection of the crown margin seal from coronal leakage.  Pleasing esthetics, when desired.  High radiographic visibility.  Biocompatibility
    30. 30. CLASSIFICATION OF POSTS (I) a. Prefabricated and Custom cast dowels b. Metallic and Non metallic dowels c. Rigid and Flexible dowels d. Aesthetic and Non aesthetic dowels (II) Barry et al Classification 1. Active posts a. Parallel sided post positioned by tapping b. Parallel self threading c. Tapered self threading 2. Passive posts a. Parallel smooth or serrated b. Tapered smooth or serrated
    31. 31. (III) Weine’s Classification a. Tapered smooth sided posts b. Parallel, serrated and vented posts c. Parallel threaded posts d. Parallel, threaded, split shank posts (IV) Ingle’s Classification a. Tapered, smooth, cemented posts b. Parallel sided cemented posts c. Tapered self threading d. Parallel, threaded inserted into prepared channels e. Parallel sided with tapered apical end, cemented in to the channel (V) Custom Cast Posts Direct and Indirect
    32. 32.
    33. 33. Passive retention posts: Cast posts Smooth tapered posts Active retention posts: Flexi posts Kurer Anchor posts III. Types of non-metal posts: A. Based on composite materials: 1.Carbon Fibre posts: Composipost Carbonite Endopost Mirafit carbon 2.Silica Fibre posts: Aesthetipost Aesthetiplus Light post Snow post Parapost fibre white Light transmitting posts: Light post Luscent anchor post Ribbon fibre posts: Ribbond (Ribbond Inc.)
    34. 34. Rigid Post systems:- Traditionally rigid post systems were metal and were either Custom cast or prefabricated. Non-metal Posts Zirconia Posts Zirconia posts are esthetic, adhesive alternatives to metal posts but also brittle and difficult to retrieve from the canal. Properties:- Titanium,Gold and Zirconium posts are biocompatible. Stainless steel contains nickel which is an allergen. Cast gold,stainless steel are all radioopaque and easily distinguished on a radiograph. Titanium and a well condensed gutta purcha share almost similar radio opacity. Crown and Bridge alloys Stainless steel Titanium-Titanium alloy Metal PostsMetal Posts
    35. 35. Recommendations:- Rigid Posts:- Less than 3 to 4mm of vertical height or when less than 25% of the tooth structure remains. Non rigid posts:- When 25 to 50% of the tooth structure is remaining. If more than 50 % of the tooth structure is remaining, no post is required.
    37. 37. Pre fabricated posts: Passive tapered posts: a) Maintains natural pericanal tooth structure. b) Mimics natural canal shape. c) Tapered shaped provide least retention. d) When there is adequate canal length for axial retention. (8 to 9 mm), and the canal is not funnel shaped, the tapered post is an ideal choice. e) Especially useful in the restoration of maxillary premolars, due to their thin, fragile, fluted, tapered root form
    38. 38. Passive parallel posts: • Greater retention. • Clinically: successful history. • Pericanal tooth structure has to be removed. • Indicated when there is increased need for retention when the preparation of the parallel canal space will not jeopardize the root integrity in the apical one third. Active post: a) Threads of the post actually engage or screw into the pericanal dentin. b) V-Lock (Brasseler) and Flexi-post (Essential dental systems) have performed well in laboratory investigations. c) Indicated when increased retention is required in a short canal space.
    39. 39. PARA POST SYSTEM They are passive, parallel, vented posts made of stainless steel or Titanium. Three Designs (a) Original Parapost (b) Para post plus (c) Unity System (i) It has a vertical groove cut through the length of its serrations, allowing axial venting. (ii) The transfer of occlusal forces of the tooth occurs through the cement layer. (iii) Cement retention is gained by horizontal serrations on the Original para post , spiral flutes and grooves on ParaPost Plus and raised diamond pattern on the Unity post.
    40. 40. BOSTON POST SYSTEM (Goldsman and Nathanson) a) It resembles parapost system without the vertical venting channel. b) 99.6% Titanium c) It is a passive post, depends upon horizontal serrations and cementing medium for retention. PARKELL PARALLEL POST SYSTEM a) Stainless steel passive, vented serrated post. b) It has an anti rotational lock which fits on to the seat produced on the root. c) It has a plastic core burn out pattern available for cast pattern
    42. 42. ACTIVE POSTS • The active posts engage the root dentine with threads they must always be cemented with a luting cement. Self-threading posts Self-threading posts have a shank (shaft) that is fractionally narrower than the post channel. a) Dentatus Screw Post
    43. 43.
    44. 44. (b)Flexi Post
    45. 45. Radix Anchor System
    46. 46. Pretapped Posts KURER POST SYSTEM (a)It has a high frequency thread around a parallel-sided shank. (b) After post space preparation counter-thread on the internal aspect of the post hole is prepared with a thread cutter. (c) Root Facer which flattens the root face onto which the head of the post seats. This unfortunately removes coronal tissue, which is important in creating a ferrule.
    47. 47.
    48. 48. • WHICH POST DESIGN PRODUCES THE GREATEST RETENTION? • Tapered cemented posts are the least retentive. Cemented, parallel-sided posts with serrations are more retentive than cemented, smoothsided parallel posts. Threaded posts are most retentive. • RELATIONSHIP BETWEEN POST FORM AND THE POTENTIAL FOR ROOT FRACTURE • All types of threaded posts produce the greatest potential for root fracture(7%), compared with tapered cemented posts (3%) and parallel cemented posts (1%).
    49. 49. Non Rigid Posts: CLASSIFICATION Carbon Fibres Silica Fibres Polyethylene Endo post Carbonite system Mirafit carbon Snow post Fibre white Mirafit white Glass Fibre Quartz Fibre Aesthetic post Style post Ribbond Construct
    50. 50. CARBON FIBRE POSTS:- • Introduced by Duret and associates(1990) in France. • They consist of continuous, unidirectional, pyrolytic carbon / graphite fibres reinforced in an epoxy resin matrix with 64% carbon. TYPES:- a) ENDOPOST:- Narrow parallel sided cylindrical posts(1 to 1.2mm) used for retention of core materials in narrow-diameter roots such as molars or mandibular incisors. b) CARBONITE SYSTEM :-Parallel sided with a 3 mm conical tip. Available in three diameters- 1.2mm, 1.35 mm and 1.5mm, with a single bur for each size.
    51. 51. Carbon Fibre Post
    52. 52. SILICA FIBRE POSTS: TYPES- GLASS FIBRE AND QUARTZ FIBRE: GLASS FIBER POSTS Glass fibers have a lower elastic modulus than carbon / graphite fibers. These posts can be made of different types of glasses. a) SNOW POST :- It is composed of 60% longitudinally arranged Silica Zirconium glass fibres in an epoxy resin matrix. It is cylindrical in shape with a 3 degrees taper. The taper is 4-6 mm long. Available in 1, 1.2, 1.4, and 1.6 mm diameters along with matching burs. b) PARAPOST FIBRE WHITE :- Designed to complement and extend the existing parapost system, fiber white has longitudinally arranged glass fibers. Post is parallel has a removable colour coded ring around the head for identification. Available in four diameters – 1.14, 1.25, 1.4 & 1.5 mm.
    53. 53. The Opaque Fiber White Post
    54. 54. Quartz Fibre:- TYPES :- • I. AESTHETI POST:- These posts retain the central core of carbon fibre bundle surrounded by quartz fibers arranged longitudinally. • II. AESTHETI PLUS POST: - Belong to the next generation of aesthetic posts and is composed entirely of quartz fibers. • III. LIGHT POST: - A translucent quartz fibre post designed to permit light curing materials to be used for leading curing light in to the canal. • All of these variations are produced in the same shapes and sizes as the original Composi post. RTD have recently introduced a series of posts with a double taper. • STYLE POST: - Parallel sided, tapered end quartz fibre post system. This is compatible with its metal prefabricated M-P post system and is produced in 4 diameters.
    55. 55. Translucent quartz-fibre posts, The DT light-post and The Luscent anchor
    56. 56. 3. WOVEN-FIBRE COMPOSITE MATERIALS/ POLYETHYLENE FIBRE MATERIALS: They are cold gas plasma treated, polyethylene woven fibres embedded in conventional resin composite, they are advocated for corono radicular stabilization of pulpless teeth. Disadvantage similar to those of fibre reinforced epoxy resin post system-Inferior strength combined with undesirable flexibility.
    57. 57.
    58. 58.
    59. 59.
    60. 60.
    61. 61. CORE The core consists of restorative material placed in the coronal area of the tooth. The core replaces carious, fractured, or missing tooth coronal structure and retains the final restoration. Desirable physical characteristics:- a) High compressive strength b) Dimensional stability c) Ease of manipulation d) Short setting time e) Ability to bond to the tooth and post
    62. 62. CORE MATERIALS • Amalgam has a long history of success. Its strength has been confirmed in laboratory studies in both static and dynamic loading. • However it possesses several disadvantages: – Dark colour potentially lowers the value of all ceramic restorations. – Causes a grey halo at the gingival margin. – Low early strength (15-20 minutes wait before core preparation.) – Messy to prepare. – Irreversible staining of the gingival margin during preparation.
    63. 63. Glass Ionomer Cement Advantages: Ease of manipulation Fluoride release Chemical bonding Disadvantage: Low fracture toughness (fracture toughness - materials ability to resist crack propagation) Attempt to increase the fracture toughness; silver reinforcement has been added to Glass Ionomer cement. Unfortunately this material also has low fracture toughness:  These materials should be used in posterior teeth in which more than 50% of the coronal tooth structure remains. 
    64. 64. Composite resin • Available as light cured, autopolymerized and dual cure formulations. • Major advantage: is the ability to be bonded to tooth structure and then to serve as a substrate to which a ceramic crown can bonded. • Laboratory studies have suggested adequate fracture toughness and compressive strength in a static load test. • However, it has not performed as successfully in dynamic load tests, that is performed in a chewing machine. • It appears to undergo plastic deformation. • Not dimensionally stable in a wet environment. As it absorbs water, the core expands and as it dries out, the core shrinks.
    65. 65. Cast Core The core is an integral extension of the post, and the core does not depend on mechanical means for retention on the post. ADVANTAGES a) The design prevents the dislodgement of the core and crown from the post and root when minimal tooth structure remains. b) Less removal of the tooth structure during fabrication. DISADVANTAGES:- a) Higher clinical rates of root fracture. b) Technique sensitive and expensive.
    66. 66. Final Restoration:- As a general rule, all endodontically treated posterior teeth and structurally damaged anterior and posterior teeth should be restored with a crown.
    67. 67. PRINCIPLES OF TOOTH PREPARATION 1. Conservation of the tooth structure:- Preparation of the canal:- a) The thickness of the remaining dentin is the prime variable in fracture resistance. b) The root canal should be enlarged only enough to enable the post to fit acuurately yet passively.
    70. 70. 2. Retention form of a Post a) Preparation geometry:- Preparation walls desire parallelism or minimal taper, elliptical canal (6 to 8 degrees) • Post surface texture:- • Luting agent:- It is of great importance if the post is lose in the canal, Adhesive resin have the potential to improve the performance of the post and core. Zinc phosphate and Glass ionomer cement have similar retentive properties. Composite resin and zinc polycarboxylate cements have slightly less. d) Post length and
    71. 71. WHAT IS THE PROPER LENGTH FOR A POST? A wide range of recommendations:- (1)The post length should equal the incisocervical or occlusocervical dimension of the crown. (2) The post should be longer than the crown. (3) The post should be one and one-third the crown length. (4)The post should be half the root length. (5) The post should be two-thirds the root length. (6) The post should be four-fifths the root length. (7) The post should be terminated halfway between the crestal bone and root apex. (8) The post should be as long as possible without disturbing the apical seal.
    72. 72. WHAT IS THE PROPER LENGTH FOR A POST? Reasonable clinical guidelines for length include the following: (1) Make the post approximately three-quarters the length of the root when treating long-rooted teeth. (2) When average root length is encountered, then post length is dictated by retaining 5 mm of apical gutta-percha and extending the post to the gutta-percha. (3) Whenever possible, posts should extend at least 4 mm apical to the bone crest to decrease dentin stress. (4) Molar posts should not be extended more than 7 mm into the root canal apical to the base of the pulp chamber.
    73. 73. Average Crown Length Average Root length 2/3 Root length 4 mm from Apex. Maxillary Teeth Central Incisor 10.8 12.5 8.3 8.5 Lateral Incisor 9.5 13.1 8.7 9.1 Canine 10.2 15.8 10.5 11.8 First Premolar 8.6 12.7 8.5 8.7 Second Premolar 7.5 13.5 9.0 9.5 First Molar 7.4 MF DF L 12.5 12.0 13.2 MF DF L 8.3 8.0 8.8 MF DF L 8.5 8.0 9.2 Second Molar 7.4 12.8 12.0 13.4 8.5 8.0 8.9 8.5 8.0 9.4 Mandiular Teeth Central Incisor 9.1 12.4 8.3 8.4 Lateral incisor 9.4 13.0 8.7 9.0 Canine 10.9 14.3 9.5 10.3 First premolar 8.7 13.4 8.9 9.4 Second premolar 7.8 13.6 9.1 9.6 First Molar 7.4 M D 13.5 13.4 M D 9.0 8.9 M D 9.5 9.4 Second Molar 7.5 13.4 13.3 8.9 8.9 9.4 9.3
    74. 74. WHAT IS THE IDEAL POST DIAMETER Instruments used to prepare posts should be related in size to root dimensions to avoid excessive post diameters that lead to root perforation.
    75. 75. 3.3. Resistance form of a PostResistance form of a Post a) Stress distributiona) Stress distribution One of the functions of the Post is to distribute the directed forces over as large anOne of the functions of the Post is to distribute the directed forces over as large an area as evenly as possible.area as evenly as possible. i)i) The greatest stress distribution is at the shoulder, particularly interproximally,The greatest stress distribution is at the shoulder, particularly interproximally, Dentin should be conserved in these areas.Dentin should be conserved in these areas. ii)ii) Parallel sided posts may distribute stress more evenly than tapered posts.Parallel sided posts may distribute stress more evenly than tapered posts. iii)iii) Sharp angles should be avoided.Sharp angles should be avoided. iv)iv) High stresses are generated during insertion, particularly with smooth, parallelHigh stresses are generated during insertion, particularly with smooth, parallel sided posts that have no vent for cement escape.sided posts that have no vent for cement escape. v)v) Threaded posts distribute stresses more evenly if the posts are backed off half aThreaded posts distribute stresses more evenly if the posts are backed off half a turn.turn.
    76. 76. b) Rotational thickness It is important that a post with a circular cross section should not rotate during function. GROOVE a) If sufficient coronal structure is present rotation is prevented by a vertical coronal wall. b) If coronal dentin is absent then a small vertical groove in the canal serves as an anti rotational element.It is located in the bulkiest area of the root. Pins Pins are used either alone or in combination with a postPins are used either alone or in combination with a post Retention for the core materialRetention for the core material Increase the resistanceIncrease the resistance Maximum of 3 pins in anterior teeth if no coronal tooth structure existsMaximum of 3 pins in anterior teeth if no coronal tooth structure exists
    77. 77.
    78. 78.
    79. 79. Custom cast posts: Long history of clinical success Circumstances in which they are the material of choice include: a) Multiple cores to be placed in the same arch (cost effective) b) Usage in small teeth. Eg. Mandibular incisors where core build up is difficult. c) Angle of the core must be changed in relation to the post. (Prefabricated systems should not be bent) d) If a large core is supposed to be placed in high stress situations.
    80. 80. Maxillary first molars have deep concavities on the furcal surface of 94% of mesio-buccal roots,31% of disto-buccal roots, and 17% of palatal roots. Mandibular first molars have root concavities on the furcal surface of all mesial roots and 99% of distal roots. Maxillary first premolars have deep mesial concavities and slender roots with thin dentine. These anatomical restrictions should be kept in mind when restoring such teeth.
    81. 81. Tooth preparation procedures:- 1. Removal of the root canal filling material to the appropriate depth. 2. Enlargement of the Canal. 3. Preparation of the coronal tooth structure.
    82. 82. 1. Removal of the root canal filling material to the appropriate depth. Q1.)How much gutta-percha should be retained to preserve the apical seal? Ans.) 4 to 5 mm should be retained apically to ensure an adequate seal. Stopping precisely at 4 mm is difficult, and radiographic angulation errors could lead to retention of less than 4 mm.Therefore, 5 mm of gutta-percha should be retained apically Goodacre and Spolnik , Journal Of Prosthodontics 1995;4
    83. 83. Removal of Endodontic filling material:- The root canal should be completely obturated in the first place so as the lateral canals get sealed. A post cannot be placed if the canal is filled with a full length silver point, so these must be removed and the canal should be retreated with gutta percha. Methods to remove Gutta Percha • Use of heated hand pluggers • Use of Chemical solvents • Use of rotary instruments
    84. 84. Use of heated hand pluggers a) A heated instrument such as a lateral compactor can be inserted in to the canal up to desired depth. b) In narrow canals system B spreader is ideal for removal. c) The hot instrument is carried in to canal and allowed to cool in the canal for up to 7-10 seconds d) An instrument such as BUCHANAN PLUGGER can be used to vertically compact the remaining gutta percha in the root canal.
    85. 85.
    86. 86. Canal filled with Gutta Percha Hot Plugger placed in the canal, apical portion intact. Serial widening of the canal Verifying Fit
    87. 87. Use of Chemical Solvents Organic solvents such as Chloroform,Eucalyptol or Xylol. Methyl Chloroform and heated eucalyptol both have good solvent action and are less toxic than chloroform ( Wennberg and Ostravik 1989 ). Disadvantage:- - Solvent evaporate from the softened Gutta percha and the latter material shrinks - It is difficult to control the depth of softening of the gutta percha and potential leakage of the solvents in to the periradicular tissues.
    88. 88. Use of Rotary instruments Rotary systems such as Peeso reamers, Gates Glidden drills are advocated for gutta Percha removal. Advantages of Peeso reamer:- Non cutting tip and Ability to remain centered in the canal The frictional heat generated during the mechanical elimination of the gutta percha aids in its removal by softening it. Softened mass is transported coronally by the direction of the flutes, slight apical pressure will condense it apically, thus improving the apical seal. Kwan and Harrington, 1981.
    89. 89.
    90. 90. PEESO REAMER SIZES Reamer Number Diameter Teeth 1. 0.7 mm Mandibular incisor 2 0.9 mm Maxillary first premolar Maxillary second molar (DF) Mandibular first molar (ML) Mandibular second molar (MF, ML) 3 1.1 mm Maxillary Second premolar Maxillary first molar (MF, DF) Maxillary second molar (MF) Mandibular first molar (MF, D) Mandibular second molar (D) 4 1.3 mm Maxillary lateral incisor Mandibular premolar Maxillary molar (L) 5 1.5 mm Canine 6 1.7 mm Maxillary central incisor
    91. 91. Coronal Tooth Preparation a) Post and core fabrication can often best be done after the coronal tooth preparation has been completed. b) Type of single crown or retainer (all-metal, all-ceramic, metal ceramic) i.e., the definitive restoration decides the reduction depths and form recommended for each type of crown/retainer.
    92. 92. Pulp Chamber Preparation The pulp chamber should be cleaned of any filling material prior to post space preparation.
    93. 93. Enlargement of the Canal. Root Selection for Multirooted Teeth Primary roots:- Palatal roots of maxillary molars and distal roots of mandibular molars. Others:- Mesial roots of molars, Post length should be 3 to 4mm and Width should be no larger than Peeso no.2 ( 1mm)
    94. 94. 1. The canal is enlarged in size using the rotary instrument that corresponds to the final dimension of the selected post.2. At least the apical half of the post should fit closely to the preparation. The coronal half of the post may not fit as well because of root canal flaring. 3. If the root canal cannot be prepared to conform to the round shape of the post and have adequate approximation to the root canal walls, then a custom-cast post may be preferable. 4. The incisal/occlusal end of the post is shortened so that it does not interfere with the opposing occlusion, but it must provide support and retention for the restorative core material ( 2-3mm). Prefabricated Cemented or Bonded Post/Restorative Material Core
    95. 95. 5. When metal posts are used, they can be bent coronally,if necessary, to align them within the core material . Post bending is done outside the mouth with orthodontic pliers. 6. If there is little or no remaining coronal tooth structure to provide resistance to core rotation, an auxiliary threaded pin (TMS pins, minimum or regular) should be placed into the remaining tooth structure
    96. 96. Temporization As root canal treatment and final restoration are not finished in a single appointment, Therefore, a tooth must be prepared for a sealing temporary. Objectives of Temporizaion: The restoration must a) Seal coronally, preventing ingress of oral fluids and bacteria and egress of intracanal medicaments. b) Protect tooth structure until the final restoration is made. c) Provide aesthetic requirements at times, but always as a secondary consideration to providing seal.
    97. 97. Types of Temporary Restoration 1. Reinforced Zinc Oxide Eugenol Cement 2. Cavit 3. Light cured composite material ( TERM ) Techniques of Placement •Coronal seal depends on the thickness of the material, a minimum of 3-4mm is required, preferably 4mm to allow for wear. •In anterior teeth, the access is oblique to the tooth surface, care must be taken to ensure that material is at least 3mm in the cingulum area. •A cotton is placed in the access cavity to prevent ingress of temporary material in the root canals. •Patient should avoid chewing on the tooth for an
    98. 98. For severely broken down tooth, At the first visit a Cusp overlay amalgam, Clayette or occasionally a well fitting orthodontic band is cemented on the tooth which provides a durable temporary restoration. At the next appointment, a conventional access cavity is made, and the bulk of the restoration is left in the place.
    99. 99. Temporary Dowels and Crowns 1. An Endopost is prepared in the same manner as for the impression to fabricate post and core. 2. The non working end of the post is bent in a cane shape to fit the coronal portion of the template. 3. Vaseline is applied on to the prepared tooth with a camel’s hair brush, if little tooth structure remains, a small amount of saliva acts as a separating media. 4. Before the template is inserted in to its place, a portion of the a creamy mix of quick setting acrylic is painted on the cane portion of the post by camel’s hair’s brush. 5. With the Endopost in its place, quick setting acrylic is poured in to the coronal portion of the template. Patient is asked to close his mouth. 6. When the acrylic reaches a rubbery consistency, the patient is instructed to open, template is removed, and the temporary restoration with the post is separated from the temporary restoration by a plastic instrument. The gross flash is cut off with the small scissors , while still in soft state, the restoration is reinserted in to the preparation and allowed to set.
    100. 100. Ion Crown form for an Individual retainer Selection of ion crown Endopost placement Quick setting acrylic placement Polished Temporary crown cemented
    101. 101. Lost coronal seal ? • Management of potentially contaminated, filled root canals:- 1. Clean the pulp chamber thoroughly. 2. Penetrate the canal orifices up to 1/3rd to ½ of the length of the canal. 3. Irrigate with NaOCl, place EDTA for 1 to 2 minutes and place 2% chlorhexidine for approx. 2 minutes. 4. Dry the canal, fill the canal with Ca(OH)2 and place a sound temporary filling. 5. Recall the patient after 1 to 2 weeks and, if symptom free, begin restoring the tooth.
    102. 102. POST FABRICATION
    103. 103. Custom-cast post and core Traumatically fractured central incisor after endodontic treatment Indirect Technique
    104. 104.
    105. 105.
    106. 106.
    107. 107.
    108. 108.
    109. 109. Prefabricated Posts
    110. 110.
    111. 111.
    112. 112.
    113. 113. NON RIGID POSTS
    114. 114.
    116. 116.
    117. 117. CEMENTATION Any of the current luting cements can be used successfully with a post if the proper principles are followed. The most common luting agents are Zinc phosphate, Resin, Glass ionomer, Resin modified glass ionomer. Recent trend is favouring resin cements due to the following a) Increased retention QI 2003;34 b) Less leakage JOE 2003;29 c) Short term strengthening of the root JOE 1984;10 The 4th generation adhesive systems ( 3 step ) should be used as they provide a better seal to radicular dentin than recent 5th generation systems. Self cure or dual cure systems are preferred.
    118. 118. Cementation of Posts An attempt should be made to place the post in the canal after the canal coated with cement to avoid air entrapment leading to voids.
    119. 119. MANAGING ROOTS WITH OPEN APEX Treatment of non-vital,permanent teeth with wide open immature apicies is difficult , as it is impossible to achieve an apical hard tissue barrier against which a root canal filling can be compacted.
    120. 120. TREATMENT MODALITIES 1. Apexification:-It is a technique that induces apical closure by the formation of mineralised tissue. Calcium hydroxide in the form a non-setting aqueous suspension is the material of choice. Disadvantages:- a) Long time required, the time taken for closure is variable,ranging from five to 19 months. J Endod 1987; 13 b) Varying success rate of apexification has been reported as 74–96%.
    121. 121. One-visit apexification An alternative to apexification over multiple visits has been the placement of a biocompatible material into the apical part of the root canal. Materials that have previously been tried are :- a) Calciumphosphate ceramic b) Surgicel with amalgam, c) Freeze-dried cortical bone d) Freeze-dried dentine and dentinal shavings.
    122. 122. • Mineral Trioxide Aggregate can be used as an apical barrier material for root-end closure. The material consists of fine hydrophilic particles of tricalcium silicate, tricalcium aluminate, tricalcium oxide and silicate oxide. When mixed with sterile water it forms a colloidal gel that sets within three to four hours.
    123. 123. Occasionally the post endodontic presentation of the canal may be too wide for routine direct restoration. The problem in restoring weakened roots is the fact that the remaining root dentine is thin and therefore prone to fracture. The Luminex light transmitting system (Dentatus) is used to rehabilitate this canal to an ideal size and shape. ROOT REINFORCEMENT
    124. 124. Procedure: • Canal is reamed to the desired depth with a size matched reamer. The reamer is correlated in size and shape to the corresponding light transmitting post (LTP) and a luscent anchor. • Light transmitting post is tried in and adjusted for length. • Canal is then dried, etched and rinsed. Bonding agent is applied in the canal and cured.•A microhybrid composite resin, Esthet X (Caulk, Dentsply) is injected into the bonded canal and the light transmitting post is pushed into the uncured composite resin to its full
    125. 125.
    126. 126. CONCLUSION A pulpless tooth has commonly lost substantial tooth structure. Consequently, an endodontically treated teeth requires a restoration that conserves and protects the remaining tooth structure. Although, there are many materials available for providing almost perfect restoration but prognosis of the pulpless teeth relies primarily on the application of sound biomechanical principles rather than on the materials used for the restoration.
    127. 127. REFERENCES
    128. 128. References:-References:- Textbooks:-Textbooks:- a)a) Endodontics:- Ingle, Bakland, 5th EditionEndodontics:- Ingle, Bakland, 5th Edition b)b) Pathways of the pulp :- Cohen S,8th EditionPathways of the pulp :- Cohen S,8th Edition c)c) Textbook of Endodontics – WeineTextbook of Endodontics – Weine d)d) Operative dentistry- SummitOperative dentistry- Summit e)e) Problem solving in endodontics- GutmannProblem solving in endodontics- Gutmann f)f) Fixed Prosthodontics- Tyllman;Shillinberg;RosensteilFixed Prosthodontics- Tyllman;Shillinberg;Rosensteil g)g) Endodontics in clinical practice- T.R Pitt FordEndodontics in clinical practice- T.R Pitt Ford
    129. 129. (1)“Restoration of the endodontically treated tooth” J. William Robbins DCNA 2002; 46:367-384. (2)“Restoration of endodontically treated teeth: An overview of clinical aspects.” Pankaj Dhawan Journal of IPS 2001 Oct; 1(3): 21-28. (3)“Esthetic Post and core treatment” George A. Freedman DCNA Jan 2001; 45(1): 103-116. (4)“Factors affecting retention of post systems: A literature review” Lawrence W. Stockton JPD 1999; 81(4): 380-385. (5)“Biomechanical criteria for evaluating prefabricated post and core systems: A guide for the restorative dentist”. Charles T. Smith et al Quintessence International 1998; 29: 305 –312.
    130. 130. (6)“The endodontically treated tooth” Restorative concepts and techniques. Kenneth C. Trabert, et al. DCNA 1984 Oct; 28(4): 923-951. (7)“Biomechanical considerations in restoring endodontically treated teeth”. David Assif et al. JPD 1994; 71: 565-567. (8)“Restoration of endodontically treated teeth: A review of literature” Stephen I. Hudis JPD 1986; 55(1): 33-38 (9)“Prefabricated dowels: A literature review. JPD 1983; 49(4): 498-503. (10)“Management of endodontically treated tooth Part I : Concept for restorative designs” Albert C. Goerig et al JPD 1983; 49(3): 340-345.
    131. 131.