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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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New microsoft office power point presentation

  1. 1. RETAINERS IN FIXED DENTAL PROSTHESIS INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. CONTENTSCONTENTS PART IPART I Introduction Requirements of retainer Criteria for selecting retainers Classification Full veneer crown retainer Metal ceramic retainer All ceramic crown retainer Pinledge retainer Partial veneer crown retainer
  3. 3. PART IIPART II Resin bonded retainer Rochette bridge Maryland bridge Virginia bridge inlays onlays Radicular retainers Failures in retainers Conclusion references
  4. 4. INTRODUCTIONINTRODUCTION All fixed partial dentures are made up of retainers that obtain support from the abutment, pontics that replace the missing tooth and connectors that connect the pontics to the retainers Retainer is defined as, part of fixed partial denture which unites abutment to the remainder of restoration
  5. 5. REQUIREMENTS OF RETAINERREQUIREMENTS OF RETAINER Biocompatible Withstand masticatory forces Restore anatomy of the tooth Pulp consideration Strength: to resist deformation under functional stresses Esthetically acceptable Maintain oral hygiene
  6. 6. CRITERIA FOR SELECTION OF RETAINERSCRITERIA FOR SELECTION OF RETAINERS 1. Degree of retention required  Most important consideration  Factors which effect retention are a.Length of the span: Longer the span greater the stress on retainers, so the components of a bridge must be stronger b.Type of bridge required Strong retainers are required for fixed-fixed bridge than fixed-movable to withstand stresses on cementing media
  7. 7. c. Strength of bite It will vary with the age, sex and muscular development of patient Heavier bite requires stronger and thicker metal to prevent failure of retainers d.Tooth or teeth to be replaced Size and position of pontic have a direct effect on type of retainer Eg: replacement of molar impart great stress to abutment than lower central
  8. 8. e. Articulation -influences the selection and design of retainer -correction of any supra erupted tooth opposing pontic area is done prior to construction of a bridge f. Habits of patient -bruxism patients should be given thicker and stronger retainer than normal because of their excessive clenching
  9. 9. 2. Surface area of the casting 3.Periodontal condition In Gingival recession –place margins supra gingivally to minimize gingival irritation 5.Effective root surface area of eruption of crown of the tooth
  10. 10. 9. Condition of abutment teeth Partial veneer crown-non-carious abutment Endodontically treated tooth- post and core Full veneer crown-large carious abutment 10. Preservation of tooth structure Partial> fullveneer >all ceramic 11.Relation with the opposing tooth
  11. 11. 12.Material used in the construction of the retainer 13.Condition of root Shape, periodontal condition and surface area are considered 14.Alignment of tooth 15.Mutiple retainers Placed by locking various retainers together with precision attachments
  12. 12. 1.EXTRACORONAL A.FULLVENEER CROWN a. Complete metal b. All ceramic c. Metal ceramic B.PARTIAL VENEER CROWN a. Anterior -3/4crown b. Posterior -3/4 crown or 4/5 crown -Reverse ¾ crown -mesial1/2crown -7/8crown C.RESIN BONDED RETAINERS 2.INTRACORONAL a. inlays b. onlays 3.RADICULAR RETAINERS
  13. 13. FULL METAL CROWNFULL METAL CROWN Introduced by W.N.Morrison-1869 INDICATIONS Extensive coronal destruction Short clinical crowns Max retention and resistance needed Axial correction needed Endodontically treated teeth
  14. 14. CONTRAINDICATIONCONTRAINDICATION If treatment objective can be met with more conservative preparation High esthetic demand When less than max retentive and resistance needed
  15. 15. ADVANTAGESADVANTAGES Highly retentive High resistance Superior strength Axial contour modification Occlusal modification
  16. 16. DISADVANTAGESDISADVANTAGES 1.more extensive preparation 2.not feasible for electrical vitality test 3.esthetic objection
  17. 17. PREPARATIONPREPARATION Includes following steps Occlusal guiding grooves Occlusal reduction Axial alignment grooves Axial reduction finishing
  18. 18. Guiding grooves  round end tapered diamond  Placed in the mesial, central, distal fossa- appx 1mm depth  Placed in buccal and lingual dev. Groove • Purpose:  occlusal reduction follows anatomic configuration and minmizes loss of tooth structure
  19. 19. Depth orientation grooves :round end tapered Half occlusal reduction done
  20. 20.
  21. 21. Chamfer and axial finishing torpedo bur Seating groove no.171Lbur
  22. 22.
  23. 23. METAL CERAMIC CROWNMETAL CERAMIC CROWN Most widely used fixed restoration Consists of Cast metal crown + layer of fused porcelain-mimics the natural tooth Requires considerable tooth reduction-to mask the metal sub-structure Strength(metal)+esthetics(porcelain)
  24. 24. INDICATIONSINDICATIONS High esthetic demand FPD retainers and single restorations for anterior and posterior teeth Mandibular anterior teeth where full shoulder is prohibited  Peg shaped laterals/teeth with morphologic deviations
  25. 25. CONTRA-INDICATIONSCONTRA-INDICATIONS a. Active caries b. Periodontally compromised teeth c. Young patients d. Where conservative treatment feasible
  26. 26. ADVANTAGESADVANTAGES A. Strength & Esthetics B. Excellent retentive qualities C. Axial form correction D. Occlusal correction
  27. 27. DIS-ADVANTAGESDIS-ADVANTAGES 1.High tooth reduction 2.Risk of periodontal disease-facial margin placed subgingivally 3.Inferior esthetic-to all porcelain 4.Expensive 5.Subjectable to stress fracture 6.Difficulty in shade selection
  28. 28. PREPARATIONPREPARATION Includes 5 steps 1.Guiding grooves 2.incisal reduction 3.labial reduction 4.Axial reduction of proximal and lingual surfaces 5.finishing
  29. 29. Guiding grooves Place 3grooves- centre,mesiofacial,distofacial line angles- parallel to long axis of the tooth-in 2 sets One parallel to gingival half of labial surface Second parallel to incisal half of labial surface Approximately 1.4mm deep
  30. 30.
  31. 31. Labial/buccal reduction Cervical plane-path of placement of restoration Incisal plane-provides space needed for porcelain veneer Resulting shoulder-1mm wide with 0.5mm apical to crest of gingiva
  32. 32. Lingual reduction  Lingual surface is reduced with Small wheel diamond to obtain a Minimum clearance of 0.7mm With the opposing teeth  Lingual surfaces that receive ceramic veneer should have 1mm Clearance  Care should be taken so that the junction between cingulum and lingual wall must not be overreduced
  33. 33. Axial reduction  -Proximoaxial and linguoaxial surfaces-reduced with torpedo diamond held llel to path of withdrawal of restoration-with a taper of 6 degree  -lingually chamfer is prepared with depth of 0.5mm width and extended buccally to blend with interproximal shoulder
  34. 34. Lingual axial reduction : torpedo diamondInitial proximal reduction : long needle diamond
  35. 35. Finishing  Axial and lingual finishing-torpedo bur  Axial and shoulder-radial fissure bur Evaluation  Margins should provide distinct resistance to vertical displacement of explorer tip
  36. 36. Axial finishing: torpedo bur Axial and shoulder finishing: radial fissure bur
  37. 37.
  38. 38. ALL CERAMIC CROWNALL CERAMIC CROWN All ceramic crowns are the most esthetically pleasing prosthodontic restorations Resembles natural tooth structure in terms of color and translucency Only drawback is highly susceptible fracture
  39. 39.
  40. 40. INDICATIONSINDICATIONS High esthetic requirement Considerable proximal caries Incisal edge reasonably intact Endodontically treated teeth with post and cores Favorable distribution of occlusal load.
  41. 41. CONTRAINDICATIONSCONTRAINDICATIONS High caries index Where treatment can be achieved by more conservative restoration Insufficient tooth structure to support to porcelain  Thin teeth facio-lingually bruxism where opposing tooth occluding in the cervical third of the crown short clinical crown
  42. 42. ADVANTAGESADVANTAGES The complete ceramic restoration has improved esthetics because of its superior translucency The restoration will have good tissue response because of inert nature of porcelain The restoration is slightly more conservative than metal ceramic in labial surface due to lack of metal reinforcement
  43. 43. DISADVANTAGESDISADVANTAGES The complete ceramic restoration will have reduced strength compared to metal ceramic because of lack of metal reinforcement The tooth reduction is more The restoration is susceptible for fracture due to brittleness of the porcelain. Mostly restricted to anteriors.
  44. 44. PREPARATIONPREPARATION Includes 5 steps 1.Guiding grooves 2.incisal reduction 3.Labial reduction 4.Axial reduction 5.finishing
  45. 45. Guiding grooves Usually placed in two sets Flat end tapered bur One set parallel to incisal Half of labial surface Second set parallel to gingival Half of labial surface Approximately 1.4mm deep
  46. 46.
  47. 47. Labial reductionLabial reduction
  48. 48. Proximal reduction and lingual reductionProximal reduction and lingual reduction Lingual reduction: s mall wheel diamond Lingual axial reduction: flat-endtapered
  49. 49. FinishingFinishing Fine-grit diamond or carbide is used. Preparation is made smooth and continuous with no unsupported enamel and 90 degree cavosurface margin.
  50. 50. PIN LEDGE PREPARATIONSPIN LEDGE PREPARATIONS Occasionally used as single restoration- only lingual surface is prepared Used as retainer for fpd to splint periodontally compromised teeth One or more proximal surfaces included in preparation design Pins extend to depth of 2mm into dentin- which provides retention and resistance
  51. 51. Pin ledge is very conservative preparation Plaque control easy-short margin length And supragingival margin
  52. 52. INDICATIONSINDICATIONS Undamaged ant teeth with low caries index On bulbous teeth unsuitable for ¾ crowns
  53. 53. CONTRAINDICATIONSCONTRAINDICATIONS High caries index Poor oral hygiene On non-vital teeth In cases where alignment of teeth will obstruct path of withdrawal of fpd
  54. 54. ADVANTAGESADVANTAGES  esthetically pleasing Min tooth preparation Lin concavity of max ant teeth can be modified with pin ledge restoration DISADVANTAGE Pinholes are difficult to place in teeth that are thin labiolingually
  55. 55. MAXILLARY CENTRAL INCISORMAXILLARY CENTRAL INCISOR PINLEDGEPINLEDGE 3 designs of pinledge Conventional ledge involving lingual surface of teeth Ledge with proximal slice Ledge with proximal groove preferance depends on tooth configuration presence/absence of caries
  56. 56. Tooth with slight proximal convexity prepared with proximal slice Tooth with small carious lesion-proximal groove
  57. 57. PREPARATIONPREPARATION PINLEDGE WITH PROXIMAL SLICE AND PROXIMAL REDUCTION Prepare proximal slice –tapered diamond-llel to path of withdrawal  purpose is-to provide room for a fixed dental prosthesis connector Proximal reduction includes proximal contact area-not to extend too far facially-alter outline form of the tooth
  58. 58. Incisal and lingual reduction Incisal bevel prepared with diamond inclined slight lingually-extends on the crest of incisal edge -remain in curvature of incisal edge-to minimize display of metal lingual reduction –football/wheel diamond-follows the lingual marginal bridge
  59. 59.
  60. 60. LEDGES AND INDENTATIONS two ledges prepared on reduced Li surface on incisal and cervical region prepared with cylindrical bur indentations in left and right side of incisal ledge and in cervical ledge-to prevent pulp exposure when pinholes are placed,indentations are just within mesial and distal marginal ridges-1.5mm inside external tooth contour
  61. 61.
  62. 62. PINHOLE PREPARATION Pilot channels- small round bur-with depth of 2mm Enlarge and deepen pilot channels with carbide bur when orientation and placement are satisfactory Bevel the junction between pinhole and indentation with round bur-slightly longer than diameter of pinhole
  63. 63.
  64. 64. PATIAL VENEER CROWNPATIAL VENEER CROWN An extra coronal metal restoration that covers only a part of clinical crown Also called as partial coverage restoration Types of partial veneer crown 1.Ant 3/4crown 2.Post3/4 crown 3.Reverse ¾ crown 4.Mesial1/2 crown 5.Post7/8 crown
  65. 65. INDICATIONSINDICATIONS Retainers for fpd where restoration of occlusal surface required Intact buccal surface Sturdy clinical crowns
  66. 66. Contra-indicationContra-indication Short clinical crown As retainer for long span FPD Anterior endodontic tooth High caries index Extensively damaged teeth Poor aligned teeth
  67. 67. AdvantagesAdvantages Conservative tooth preparation Accessibility Less gingival involvement Good/complete seating of prosthesis Feasible to electrical vitality test
  68. 68. Dis-advantagesDis-advantages Less retentive/resistant than full crown Limited path of withdrawal Requires dextrisity from operator Cannot be used on nonvital tooth
  70. 70. Steps in preparationSteps in preparation 1. incisal reduction 2. Lingual reduction 3. Inter-proximal reduction 4. Proximal box or groove placement 5. incisal offset placement 6. Facial bevel 7. Finishing the preparation.
  71. 71. Incisal reductionIncisal reduction Use a tapered, round-ended diamond. Reduce the incisal edge 1mm at 45 degree angle to the long axis of the tooth.
  72. 72. Lingual reductionLingual reduction Use a football-shaped diamond. Reduce lingual surface leaving a slight ridge running incisogingivally along the center of the lingual surface. Clearance with the opposing teeth should be atleast 0.7mm to 1mm.
  73. 73. LINGUALGINGIVAL REDUCTION Using tapered, round-ended diamond, make a chamfer 0.5mm deep at the cervical finish line. This is usually parallel to the incisal two third of the labial surface.
  74. 74. Interproximal reductionInterproximal reduction Reduce the proximal surface by moving the bur from lingual to the facial surface. Position the bur so that the tip of the bur is farther facial than the shank.
  75. 75. Facial line angles must remain intact to produce esthetically acceptable results. Establish a light chamfer on the proximal surface, blending it with the lingual chamfer. Break the contact with adjacent teeth.
  76. 76. Proximal groovesProximal grooves Using 167 carbide bur, place the proximal grooves parallel to the incisal two thirds of the facial surface. Grooves resist the lingual displacement. Grooves are a minimum of 3mm long and terminate 0.5mm of the gingival finish line. The facial and lingual walls of the grooves have a 2 to 5 degree incisal divergence.
  77. 77.
  78. 78. Incisal groove/offsetIncisal groove/offset Using inverted cone bur develop a 0.5 to 1mm groove connecting the proximal grooves. The grooves should be in dentine. Groove is not placed at the expense of the incisal edge.
  79. 79. Facial bevelFacial bevel Using a fine, flame-shaped bur, develop a narrow bevel less than 0.5mm on the labioincisal finish line at right angles to the incisal two thirds of the facial surface.
  80. 80. Finishing the preparationFinishing the preparation Using finishing bur, round the line angles to ensure continuity of all finish lines.
  81. 81.
  82. 82.
  83. 83. Thank you For more details please visit