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


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

  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education
  3. 3. CONTENTS 1. Introduction. 2. Definitions 3. History 4. Review of literature 5. Changes in endodontically treated teeth. 6. Pretreatment evaluation.
  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 iv) Materials used for fabrication
  5. 5. v) Recent advances in post 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) Failures 14) Summary 15) Conclusion 16) References
  8. 8. A tooth that has been pulpally involved is often given a second chance with endodontic treatment. However, in most instances endodontically treated teeth have been exposed to a variety of insults ranging from caries, the operative procedures that follow,
  9. 9. 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.
  10. 10. 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.
  11. 11. 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.
  12. 12. Restoration of the pulpless teeth has been dated back to the 1740’s where posts were fabricated of gold or silver .Ever since then a variety of techniques and materials have been introduced to reinforce the endodontically treated tooth.
  14. 14. Dowel : a post, usually made of metal that is fitted into a prepared root canal of a natural tooth. When combined with an artificial crown or core, it provides retention and resistance for the restoration (GPT-7)
  15. 15. Core : the center or base of a structure Post-core crown: a restoration in which the crown and cast post is one unit
  16. 16. Ferrule (GPT-7): l: a metal band or ring used to fit the root or crown of a tooth 2: any short tube for making a tight joint
  17. 17. • Apex (GPT-7): in dentistry, the anatomic end of a tooth root. • Biologic width: the combined width of connective tissue and epithelial attachment superior to the crestal bone
  18. 18. HISTORY
  19. 19. In 1747, Pierre Fauchard described the process by which roots of maxillary anterior teeth were used for the restoration of single teeth and the replacement of multiple teeth.
  20. 20. A 6 unit bridge, pivoted in lateral incisor, with canines cantilevered
  21. 21. Posts were fabricated of gold or silver and held in the root canal space with a heat-softened adhesive called “mastic” (prepared by gum, turpentine and white coral powder).
  22. 22. In Fauchard’s days, replacement crowns were made from bone, ivory, animal teeth, and sound natural tooth crowns. Gradually, the use of these natural substances declined, and were replaced by porcelain.
  23. 23. • A pivot (what is today termed a post) was used to retain the artificial porcelain crown into a root canal, and the crown-post combination was termed a “pivot crown.” • In the early 1800s Dubois de Chemant described Porcelain pivot crowns.
  24. 24. • Early pivot crowns used seasoned wood (white hickory) pivots. The pivot was adapted to the inside of an all-ceramic crown and also into the root canal space. Moisture would swell the wood and retain the pivot in place.
  25. 25. • Subsequently, pivot crowns were fabricated using wood/metal combinations, and then more durable all-metal pivots were used.
  26. 26. Metal pivot retention was achieved by various means such as threads, pins, surface roughening, and split designs that provided mechanical spring retention.
  28. 28. Hamilton et al ( JPD 1959:9;639) In their article, Porcelain dowel crowns, discussed about the method of fabrication and various advantages and disadvantages of porcelain as restorative material
  29. 29. Silverstein et al ( JPD 1964: 14;372) in their article, Reinforcement of weakened pulpless tooth, stated that, for the success of the restoration, the post selected should be longer than the crown
  30. 30. Colley et al ( BDJ 1968;124;63-69) did a study on the effect of post length on the retention of post and concluded that increasing the length of post in teeth increases the retention of post.
  31. 31. Goldrich M et al (JPD 1970;23:173) in his article on ‘construction of posts for teeth with existing restorations’, mentioned that the post length should equal the incisocervical or occlusocervical dimension of the crown.
  32. 32. H.G.Kurer et al (JPD 1977;38:515) Did a study to assess the axial retention of dowels. They concluded that threaded dowels appear to have better resistance to axial displacement than other types.
  33. 33. Guzy et al (JPD 1979:42;39) did invitro study on the effects of post placement on endodontically treated teeth and concluded that when the tooth is loaded, stresses are greatest at the facial and lingual surfaces of the root ( lingual surface is in tension, while facial surface is in compression), while the centrally located post lies in the neutral axis (ie only minimally stressed) and thus, does not help prevent fracture
  34. 34. • 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.
  35. 35. 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. As the level of gutta-percha increased to 7 mm the degree of leakage decreased. At least 5 mm of gutta-percha is necessary for an adequate apical seal.
  36. 36. John A. Sorensen et al ( JPD 1984;52:28) in the article ‘ Clinically significant factors in dowel design’ concluded that: • The cast parallel-sided serrated dowel and core and the parallel-sided serrated dowel with an amalgam or composite resin core recorded the highest success rate. • The tapered cast dowel and core display a higher failure rate than teeth treated without intracoronal reinforcement.
  37. 37. • Teeth that had a dowel length equal to or greater than the crown length had a success rate of 97%.
  38. 38. 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 the cores to moisture.
  39. 39. 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
  40. 40. Ryle A. Radke et al (JPD 1988;59:318) Did a study to compare the retentive values of 4 luting agents (Zinc phosphate, glass ionomer , polycarboxylate cement and a composite resin ) for ability to retain posts in prepared root canals of extracted teeth. Zinc phosphate and glass ionomer cements were found to be more retentive than polycarboxylate cements and composite resins.
  41. 41. Rahmat A et al ( JPD 1989:61:676-678) did a study to examine the effect of metal collar (with approx. 3 degree taper) on the resistance of endodontically treated roots to fracture. They concluded that reinforcement with metal collar is necessary to enhance resistance to root fracture.
  42. 42. 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 disturbe apical seal to a greater extent.
  43. 43. Felton D.A et al (JPD 1991;65:179) did a study on the effect of post design on incidence of root fracture and concluded that: • There were no statistically significant differences in the incidence of root fracture among any of the dowel systems evaluated regardless of shape, taper or presence or absence of threads.
  44. 44. • Most of the root fractures resulting from dowel insertion occurred on the mesial or distal root surfaces as a result of reduced thickness of dentin and the presence of external depressions (flutes) on these surfaces.
  45. 45. Hemmings et al (JPD 1991;66:325-329) did a study and investigated the resistance of various post and core designs to torsional forces and concluded that cervical collar form design was the most favorable design, embracing resistance and decreasing tooth fractures.
  46. 46. Anthony H.L. Tjan et al (Q Int. 1992;23:839) • Did a study to evaluate the effect of eugenol- containing endodontic sealer on retention of prefabricated pots luted with adhesive composite resin cement. They concluded that: • Eugenol significantly reduced the retention of parapost dowels luted with panavia composite resin cement.
  47. 47. Irrigating the post space with alcohol or etching with phosphoric acid gel effectively restored the retention. • The use of alcohol (ehtyl alcohol/ethanol) as a canal irrigant or etching with 37% phosphoric acid gel was found to be effective in restoring the resistance to dislodgement of post. Irrigation with alcohol produced a more consistant and reliable result.
  48. 48. Daniel B et al (JPD 1994: 72;591-594) Did a study to evaluate the retention of pre formed posts with four different cements • Panavia (Kuraray), • All- Bond 2 ( Bisco), • C&B Meta bond (parkel) and • Ketac-Cem (ESPE-Premier). They concluded that C&B Meta bond was most retentive, while no difference in retention was found between Ketac-Cem and Panavia cements. All- Bond 2 was the least retentive cement.
  49. 49. Arturo M et al (JPD 1998;80:527) • Did a study to compare the fracture resistance of two types of restorations: teeth restored with pre fabricated carbon fiber posts and composite cores to cast dowel-core restored teeth. They concluded that
  50. 50. • Significantly higher fracture threshold values were obtained in the cast post core group. Teeth restored with carbon fiber post and composite cores typically showed failure of the post core interface before the fracture of the tooth occurred. This failure occurred in response to acceptably high loads. By contrast, teeth restored with cast post and core typically showed fracture of the tooth.
  51. 51. • Steele et al ( J endod 1999:25;6) did an invitro study on the fracture strength of endodontically treated premolars and concluded that premolars with access openings or conservative MOD preparations can be restored to nearly normal cusp fracture values with dentine bonding and composite resin systems, but this strengthening may only be temporary.
  52. 52. Flemming et al ( IJP 1999: 12;78-82) did a study on the influence of post length and crown ferrule length on the fracture resistance of post and concluded that an increase in ferrule length is more important than post length.
  53. 53. Mary Rafter et al (J Prosthet Dent 2003;89:360-7.) Did study to compare the effect of fiberreinforced composite post systems on the fracture resistance and mode of failure of endodontically treated teeth. Results show that the load to failure of the stainless steel posts were significantly stronger than all the composite posts studied. However, the mode of failure or deflection of the fiberreinforced composite posts is protective to the remaining tooth structure.
  54. 54. M. ROSENTRITT et al (Journal of Oral Rehabilitation 2004 31; 675–681) • Did a study to compare the fracture resistance and marginal adaptation of allceramic incisor crowns with all-ceramic posts, glass–fibre-reinforced posts and titanium posts as well as a control without any post. • The results showed that the restored teeth without posts showed no significantly different fracture strength compared with teeth with the titanium system.
  55. 55. • The all-ceramic posts and the glass–fibrereinforced posts both provided a significant higher fracture resistance than the teeth without posts. • The greatest marginal gap was found with the titanium system at the interface cementcrown and with the all-ceramic posts at the transition between cement-tooth. • Regarding fracture resistance and the marginal adaptation, the all-ceramic and FRC posts may be considered as an alternative to the commonly used titanium post restorations.
  56. 56. Emine Y. et al ,(J Prosthodont 2005;14:8490.) Did a study to compare fracture strengths of teeth restored with cast metal and ceramic dowel and cores supporting all-ceramic crowns. The comparison between metal and ceramic dowel and cores did not reveal significant differences in spite of the fact that In-Ceram Spinells had lower mean fracture values. The fracture strength of all groups was remarkably higher than forces applied to anterior Teeth.
  57. 57. They concluded that In-Ceram Spinell and IPS Empress 2 ceramic dowel and cores may be candidates for the restoration of endodontically treated anterior teeth, as the fracture strengths of these restorations are above the maximum occlusal forces of natural dentition.
  59. 59. 1. Loss of tooth structure. 2. Altered physical characteristics. 3. Altered esthetic characteristics of the residual tooth.
  60. 60. 1. Loss of tooth structure.
  61. 61. Reeh et al (J Endod 1989:15;512-516) Evaluated the effects of endodontic procedures as compared to restorative reduction of tooth. They concluded that endodontic procedures reduce tooth stiffness by only 5% (attributed primarily to the access opening), while restorative procedures causes appreciable loss of tooth stiffness
  62. 62. Endodontic procedures reduce tooth stiffness by only 5%
  63. 63. MOD cavity decreases stiffness > 60%
  64. 64. The endodontic access into the pulp chamber destroys the structural integrity provided by the coronal dentin of the pulpal roof and allows greater flexing of the tooth under function.
  65. 65. When tooth structure is significantly reduced, Fracture of undermined cusp Or Fracture of tooth in the area of Smallest circumference (Frequently CEJ)
  66. 66. The decreased volume + The effect of prior dental procedures Significant potential for fracture of the endodontically treated teeth.
  67. 67. 2. Altered physical characteristics
  68. 68. Changes that takes place in endodontically treated teeth: a) Changes in collagen cross linking b) Dehydration of the dentine c) Changes due to use of sealer cements.
  69. 69. a) Changes in collagen cross linking Collagen Structure of dentine
  70. 70. Rivera et al ( J Endod 1988: 14;195) did a study on dentine collagen cross links of root filled and normal teeth. They concluded that the root canal treated teeth have more immature and fewer mature crosslinked collagen fibers. Thus leading to decrease in tensile strength. These changes in cross links may contribute to brittleness of nonvital teeth.
  71. 71. B) Dehydration of the dentine ( loss of moisture) Helfer et al ( OOO 1972: 34;661-670) did a study to determine the moisture content of vital and pulpless teeth and concluded that there was 9% less moisture in calcified tissues of pulpless teeth than in vital teeth. This moisture loss may increase brittleness.
  72. 72. Messer et al (J. Endod. 1994:10;91-93) did a study to measure the moisture content of vital and endodontically treated teeth and concluded that there was no statistically significant difference in moisture content of both.
  73. 73. Stephen Cohen : Path ways of pulp: 8th edt.) Changes in collagen cross-linking and dehydration of the dentin result in a 14% reduction in strength and toughness of endodontically treated molars.
  74. 74. C) Changes due to use of sealer cements May effect the properties of endodontically treated teeth
  75. 75. Jonck et al (J Endod 1979; 5: 20-24) did an analysis of the root dentine in teeth treated endodontically with ZOE sealers and concluded that in sealers containing ZOE, free Zinc competes with calcium binding sites on the surface of hydroxyapatite crystals. But it is not clear whether Zinc causes changes in physical properties of dentine.
  76. 76. • Biven et al ( BDJ 2005) in their study showed that the eugenol present in the eugenol containing root canal sealers increases the microhardness of dentine.
  77. 77. 3. Altered esthetic characteristics .
  78. 78. • A) Biomechanically altered dentin modifies light refraction through the tooth and modifies its appearance. • B) Inadequate endodontic cleaning and shaping of the coronal area  staining the dentine from degradation of vital tissue left in the pulp horns.
  79. 79. C) Caries, restorations and secondary calcifications modify the appearance.
  81. 81. Before restoring, the endodontically treated tooth should be assessed for : • Endodontic evaluation • Periodontal evaluation: • Esthetic evaluation • Restorative evaluation
  82. 82. Endodontic evaluation
  83. 83. CHECK FOR • Apical seal • No tenderness on percussion • No draining sinus. • No mobility • No active inflammation
  84. 84. Inadequate root fillings retreatment
  85. 85. Signs of failure Retreatment
  86. 86. Obturation performed with silver cones Retreatment
  87. 87. If doubt  observe until there is definitive evidence of success or failure.
  88. 88. Periodontal evaluation:
  89. 89. In addition to performing a routine periodontal evaluation (pocket depth, bleeding on probing etc), the effect of the planned restoration on the attachment apparatus must be considered.
  90. 90. Attempts to place the restorative margins on solid tooth structure Invade the biological attachment zone. In such cases, Crown lengthening orthodontic extrusion
  91. 91. Restorative evaluation Comprises of estimating the strategic importance of the tooth
  92. 92. Need extensive treatment Most Distal tooth Long span bridge Avoid DEB RPD Intermediate abutment
  93. 93. • Reliability of tooth after restoration should be considered. • Tooth must be able to withstand functional forces placed on it. • Large amount of missing tooth structure must be replaced by post n core and crown.
  94. 94. Esthetic evaluation
  95. 95. • Thin gingiva may transmit a shadow of dark root color through the tissue. • Metal or dark, carbon fiber dowels or amalgam placed in the canal can result in unacceptable gingival discoloration from the underlying root.
  96. 96. • The translu-cency of all-ceramic crowns must be considered in the selection of dowel and buildup materials. • Tooth-colored carbon fiber post, glass fiber, or zirconia posts can be used in esthetic areas. • Tooth-colored, rather than opaque, composite core material should be selected for the esthetic case.
  98. 98. Important considerations are: • The amount of remaining tooth structure • The anatomic position of the tooth • The functional load on the tooth • The esthetic requirements for the tooth
  99. 99. 1. The amount of remaining tooth structure
  100. 100. The amount of tooth structure damage is one of the most important aspects in restoration of the endodontically treated tooth.
  101. 101. Christensen et al (JADA1998:129:96) Teeth with more than half of the tooth structure intact can be restored Conservatively with coronal restorations and without dowels inside the roots.
  102. 102. • Teeth with extensive tooth structure loss  weak making dowels, cores, and crowns necessary.
  103. 103. Teeth with minimal remaining tooth structure present several problems :
  104. 104. The amount of remaining dentin is far more significant to the longterm prognosis of the restored tooth than is the selection of artificial dowel, core, or crown materials.
  105. 105. • Additional dentine at the marginal area, when encased by the crown margin or ferrule provides greater protection than dowel and core considerations.
  106. 106. Treatment planning requires use of dental specialties • to obtain the necessary sound tooth structure • to design the dowel-core-crown complex for atraumatic retention and • also recognize when the prognosis is poor .
  107. 107. 2. The anatomic position of the tooth
  108. 108. Anterior teeth • Intact, nonvital, anterior teeth minimal risk for fracture. • Restorative treatment sealing of the access cavity.
  109. 109. significant loss of tooth structure crown supported and retained by the dowel and core.
  110. 110. • Hunter et al ( JPD 1992:68;421) and Guzy et al (JPD 1979:42;39) did invitro study on the effects of post placement on endodontically treated teeth and concluded that when the tooth is loaded, stresses are greatest at the facial and lingual surfaces of the root (lingual surface is in tension, while facial surface is in compression), while the centrally located post lies in the neutral axis (ie only minimally stressed) and thus, does not help prevent fracture
  111. 111.
  112. 112. Disadvantage of routine use of cemented post in intact anterior teeth: • Requires additional operative procedure • Removes additional tooth structure for post space preparation.
  113. 113. • May be difficult to restore the teeth later when crown is needed, because this post may fail to provide adequate retention for the core material. • Post can complicate or prevent further endodontic re treatment if it becomes necessary.
  114. 114. 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.
  115. 115. When extensive tooth loss or tooth will be serving as abutment for FPD or RPD  complete coverage is must.
  116. 116.
  117. 117. Posterior teeth •Subjected to greater loading than anterior •More susceptible to fracture
  118. 118. Should receive cuspal coverage to prevent fracture
  119. 119. Significant loss of tooth structure post and core
  120. 120. • Steele et al ( J endod 1999:25;6) did an invitro study on the fracture strength of endodontically treated premolars and concluded that premolars with access openings or conservative MOD preparations can be restored to nearly normal cusp fracture values with dentine bonding and composite resin systems, but this strengthening may only be temporary.
  121. 121. 3. Functional load of the tooth
  122. 122. teeth as abutments for fixed or removable partial dentures bear more horizontal and torquing forces need more extensive protective and retentive features in the restoration.
  123. 123.
  124. 124. Abutment teeth for long-span fixed bridges and DEB RPD absorb greater transverse loads and require more pro-tection than do abutments of smaller bridges or tooth supported removable partial dentures.
  125. 125. Teeth that exhibit extensive wear from bruxism, heavy occlusion require the full complement of dowel-core-crown
  126. 126. 4. Esthetic requirements of the tooth
  127. 127. Anterior teeth, premolars, and often the maxillary first molar come in the esthetic zone of the mouth. Alterations to the color or translucency  negative impact on the esthetics of this zone.
  128. 128. • Careful selection of restorative materials . • Restorative materials include: Tooth colored dowels, Tooth colored composite resin or ceramic cores, Tooth colored cements and Ceramic crowns.
  129. 129. Thank you Leader in continuing dental education