Pontic/ orthodontic straight wire technique

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Pontic/ orthodontic straight wire technique

  1. 1. 1 INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. 2www.indiandentalacademy.com
  3. 3. 3www.indiandentalacademy.com
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  5. 5. 5 • Introduction • History • Definitions • Requirements • Basic principles of pontic design • Principle considerations in pontic designing • Specifications for Pontic Design • Classifications • Pretreatment assessment • Pontic designs • Summary • Conclusion • References www.indiandentalacademy.com
  6. 6. 6 • Replacement of a missing tooth is not a simple replacement, because placing an exact anatomic replica of the tooth in the space would be hygienically unmanageable. •Replacement of a missing tooth is a compromise at best • Its name is derived from the Latin pons, meaning bridge. •The design of the prosthetic tooth will be dictated by – Esthetics, – Function, – Ease of cleaning, – Maintenance of healthy tissue on the edentulous ridge, www.indiandentalacademy.com
  7. 7. 7 History • Ancient relics of early civilization – detached natural teeth from one mouth adjusted to another by means of ligature wires • Phoeniceans were the first to construct dental bridge work • Kerr & Roger in 1877 suggested that teeth of ivory or bone secured by copper wire or catgut string were used in china for ages before they were introduced to Europe • Pierre Fouchard 1923- Father of modern dental prosthesis • He used “Tenons” which were in reality dowels or pivots screwed into the roots to retain some of his bridges www.indiandentalacademy.com
  8. 8. 8 • Seldberg in 1936 – Gold or porcelain or combination of two • Restoration must meet – Protection, – Comfort – Esthetics – Durability – Utility www.indiandentalacademy.com
  9. 9. 9 Definitions “An artificial tooth on a FPD that replaces a missing natural teeth, restores function, & usually fills the space previously occupied by the clinical crown”. GPT “An artificial tooth suspended from the abutment teeth is a pontic” -Shillingberg HT “Pontics are the artificial teeth of a fixed partial denture that replace missing natural teeth, restoring function and appearance” -Rosenstiel SF www.indiandentalacademy.com
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  11. 11. 11 REQUIREMENTS  Restore function.  Provide esthetics and comfort.  Be biologically acceptable.  Permit effective oral hygiene.  Preserve underlying residual mucosa  Adequate strength  Colourstability  Do not overload the abutment tooth  Non irritant www.indiandentalacademy.com
  12. 12. 12 Basic Principles of pontic design Cleansability Appearance Strength Becker & Kaldahl in JPD 1981– Current theories of crown contour, margin placement, and pontic design Guidelines •Buccal and lingual contours are flat •Embrasure spaces should be open •Contact should be high •Furcation should be fluted •For posterior spaces – modified ridge lap •For anterior spaces - ridge lap www.indiandentalacademy.com
  13. 13. 13 Cleansability • All surfaces of the pontic, especially adjacent to the saddle, should be made as cleansable as possible. • They must be smooth and highly polished or glazed, not contain any junctions between materials. • The embrasure space and connectors should be smooth and cleansable. www.indiandentalacademy.com
  14. 14. 14 Appearance • Where the full length of the pontic is visible, it must look as tooth like as possible. • In premolarand first molarregion it is often possible to strike a happy compromise between reasonable appearances forthose parts of the pontic that are visible and good access for cleaning towards the ridge.www.indiandentalacademy.com
  15. 15. 15 Strength • The longerthe span, the greaterthe occlusal gingival thickness of the pontic should be. • All pontics should be designed to withstand occlusal forces; but porcelain pontics in the anteriorpart of the mouth may not of course be accepted to withstand accidental traumatic force. www.indiandentalacademy.com
  16. 16. 16 PRINCIPLECONSIDERATIONSIN PONTIC DESIGNING • Biological consideration • Esthetic consideration • Mechanical Consideration Fayyad and Al-rafee, J Oral Rehabil 1996 •156 dental bridges – college of dentistry •Material used was metal ceramic, •Results – rate of bridge failure 35.5% •Reasons for failure •Periodontal disease – 36.6% •Secondary caries – 23.2% •Pontics used •Modified ridge lap – 50.8% •Saddle type – 59.6% www.indiandentalacademy.com
  17. 17. 17 BIOLOGICALCONSIDERATION • The biologic principles of pontic design pertain to the maintenance and preservation of the residual ridge, abutment and opposing teeth, and supporting tissue. – Ridge contact – Oral hygiene considerations – Pontic materials – Occlusal forces www.indiandentalacademy.com
  18. 18. 18 Ridge contact • Pressure free contact between the pontic and the underlying tissues is indicated to prevent ulceration and inflammation of the soft tissues. • If any blanching of the soft tissue is observed at try-in, the pressure area should be identified with a disclosing medium (i.e., pressure- indicating paste) and the pontic re contoured until tissue www.indiandentalacademy.com
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  20. 20. 20 • This passive contact should occur exclusively on keratinized attached tissue. • When a pontic rests on mucosa, some ulceration may appearas a result of the normal movement of the mucosa in contact with the pontic. www.indiandentalacademy.com
  21. 21. 21 Oral hygiene considerations • The chief cause of ridge irritation is the toxins released from microbial plaque, which accumulate between the gingival surface of the pontic and the residual ridge, causing tissue inflammation and calculus formation. • Patients must be taught efficient oral hygiene techniques, with particularemphasis on cleaning the gingival surface of the pontic. www.indiandentalacademy.com
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  24. 24. 24 • Where tissue contact occurs, the gingival surface of a pontic is inaccessible to the bristles of a toothbrush. Therefore, excellent hygiene habits must be developed by the patient. • Devices such as proxy brushes, pipe cleaners, super floss, and dental floss with a threaderare highly recommended. www.indiandentalacademy.com
  25. 25. 25 • Sten RS in JPD 1958 • “for a patient to maintain good oral hygiene to prevent formation of plaques and to enjoy the assurance of longevity of post dental restoration” • Glazed porcelain presented to gingival tissue is indispensable factor in pontic www.indiandentalacademy.com
  26. 26. 26 Pontic material • Any material chosen to fabricate the pontic should provide good esthetic results where needed; – Biocompatibility, – Rigidity, – Strength to withstand occlusal forces; – Longevity. • FPDs should be made as rigid as possible, because any flexure during mastication or Para function may cause pressure on the gingiva and cause fractures of the veneering material. www.indiandentalacademy.com
  27. 27. 27 • Metal ceramic pontics are stifferand withstand occlusal forces betterif they are made fairly thick and if the porcelain is carried right round them ,from the occlusal to the ridge surface, leaving only a line of metal visible on the lingual surface ornone at all www.indiandentalacademy.com
  28. 28. 28 • Occlusal contacts should not fall on the junction between metal and porcelain during centric oreccentric tooth contacts, norshould a metal ceramic junction occurin contact with the residual ridge on the gingival surface of the pontic. www.indiandentalacademy.com
  29. 29. 29 • Clayton JA in JPD 1970 • Concluded that test surfaces of glazed porcelain were significantly rougher than polished test surfaces of either acrylic resin or cast gold • Behrend DA in JPD 1981 & Henry PJ in JPD 1966 • STATED THAT GLAZED PORCELAIN WAS MOST HYGIENIC MATERIAL USED AND IT IS SUPERIOR IN TERMS OF ESTHETICS AND CLEANING www.indiandentalacademy.com
  30. 30. 30 Occlusal forces • Potentially harmful forces are more likely to encounterif an FPDis loaded by an accidental biting on a hard object orPara functional activities like bruxism ratherthan by chewing food of uniform consistency. www.indiandentalacademy.com
  31. 31. 31 • These forces are not reduced by narrowing the occlusal table • Narrowing the occlusal table may impede or even preclude the development of harmonious and stable occlusal relationship. • Forthese reasons pontic with normal occlusal width of at least on the occlusal third are generally recommended www.indiandentalacademy.com
  32. 32. 32 Mechanical considerations • Mechanical problems may be caused by – Improperchoice of materials, – Poorframework design, – Poortooth preparation, – Poorocclusion. • These factors can lead to fracture of the prosthesis ordisplacement of the retainers. • Long-span posteriorFPDs are particularly susceptible to mechanical problems.www.indiandentalacademy.com
  33. 33. 33 Failure of a long span metalFailure of a long span metal ceramic FPDdue to highceramic FPDdue to high stressstress www.indiandentalacademy.com
  34. 34. 34 • A strong all-metal pontic may be needed in high-stress situations ratherthan a metal- ceramic pontic which would be more susceptible to fracture. • When metal ceramic pontics are chosen, extending porcelain onto the occlusal surfaces to achieve betteresthetics should also be carefully evaluated. www.indiandentalacademy.com
  35. 35. 35 AVAILABLE PONTIC MATERIALS • Some fixed partial dentures are fabricated entirely of – metal, – porcelain, – oracrylic resin, – but most use a combination of metal and porcelain. • Acrylic resin veneered pontics have had limited acceptance because of theirreduced durability (wearand discoloration). www.indiandentalacademy.com
  36. 36. 36 • The newerindirect composites, based on high inorganic-filled resins and the fiber- reinforced materials used in composite resin and resin-veneered pontics. www.indiandentalacademy.com
  37. 37. 37 Metal-ceramic Pontics. Most pontics are fabricated by the metal- ceramic technique. •A well fabricated metal-ceramic pontic is –strong, easy to keep clean, –and looks natural. www.indiandentalacademy.com
  38. 38. 38 Resin veneered Pontics. • Historically acrylic resin-veneered restorations had deficiencies that made them acceptable only as long term provisionals. • Theirresistance to abrasion was lowerthan enamel orporcelain, and noticeable wear occurs with normal tooth brushing. www.indiandentalacademy.com
  39. 39. 39 ADVANTAGES OVERCERAMICS – They are easy to manipulate and repair and do not require the high melting range alloys needed formetal-ceramic techniques. – New generation indirect resin have a higherdensity of inorganic ceramic filler than traditional direct and indirect composite resin. www.indiandentalacademy.com
  40. 40. 40 FIBER REINFORCED COMPOSITE RESIN PONTICS • Composite resin can be used in FPDwithout a metal substructure • A substructure matrix of impregnated glass orpolymerfiberprovides structural strength. www.indiandentalacademy.com
  41. 41. 41 ESTHETIC CONSIDERATIONS • No matterhow well biologic and mechanical principles have been followed during fabrication, the patient will evaluate the result by how it looks, especially when anterior teeth have been replaced. • Many esthetic considerations that pertain to single crowns also apply to the pontic. Several problems unique to the pontic may be encountered when attempting to achieve a natural appearance. www.indiandentalacademy.com
  42. 42. 42 The gingival interface • An esthetically successful pontic SHOULD replicate – The form, – Contours, – Incisal edge, – Gingival and incisal embrasures, – Colorof adjacent teeth. • The pontics simulation of a natural tooth is most often betrayed at the tissue-pontic interface. www.indiandentalacademy.com
  43. 43. 43 • The greatest challenge here is to compensate foranatomic changes that occur afterextraction. Special attention should be paid to the contourof the labial surface as it approaches the pontic-tissue junction to achieve a natural appearance • This cannot be accomplished by merely duplicating the facial contourof the missing tooth, because aftera tooth is removed, the alveolarbone undergoes resorption and/or remodeling.www.indiandentalacademy.com
  44. 44. 44 • If the pontic is poorly adapted to the residual ridge, there will be an un natural shadow in the cervical area but looks odd and spoils the illusion of the natural tooth. • Additional recesses acquiring at the gingival interface will collect food debris further betraying the illusion of the natural teeth. www.indiandentalacademy.com
  45. 45. 45 • Edelhoff, spiekermann and yildirim in Quintessence Int 2002 • Pontic design is primarily influenced by esthetic and phonetic considerations • Local defects of the alveolar ridge often complicate restorative measures • They advocated modification of the pontic design and pretreatment of the recipient site for the pontic www.indiandentalacademy.com
  46. 46. 46 SPECIFICATIONS FOR PONTIC DESIGN: •POSTERIOR PONTIC DESIGN •ANTERIOR PONTIC DESIGN www.indiandentalacademy.com
  47. 47. 47 • All surfaces should be smooth and convex and properly finished • Contact with the labial mucosa should be minimal and pressure free • Esthetics may require a long area of contact to prevent the “black space appearance” ANTERIOR PONTIC DESIGN www.indiandentalacademy.com
  48. 48. 48 POSTERIOR PONTIC DESIGN • All surfaces should be convex and properly finish • Contact with buccal contagious slope should be minimal and pressure free • Buccal and lingual shunting mechanism should confirm to that of adjacent teeth • The occlusal table must be in functional harmony with the occlusion of all the teeth. • The overall length of the buccal surface should be equal to that of the adjacent abutment teethwww.indiandentalacademy.com
  49. 49. 49 CLASSIFICATION OF PONTICS •Based on relation to soft tissues •Based on materials used •Prefabricated pontics •Based on retention used for facing www.indiandentalacademy.com
  50. 50. 50 I BASED ON RELATION TO SOFT TISSUES A -Mucosal contact – Ridge lap/saddle – Modified ridge lap – Ovate – Conical B- No Mucosal contact • Sanitary (hygienic) • Modified sanitary(hygienic) www.indiandentalacademy.com
  51. 51. 51 II BASED ON MATERIALS USED A - Metallic – Gold alloys – Nickel chromium alloy B - Non Metallic • Acrylic • Porcelain C - Combination-alloys with acrylic or porcelain www.indiandentalacademy.com
  52. 52. 52 III PRE FABRICATED PONTICS • Trupontic • Interchangeable facing • Pin facing • Modified pin facing • Reverse pin facing • Harmony facing • Porcelain fused to metal www.indiandentalacademy.com
  53. 53. 53 IV BASED ON TYPE OF RETENTION USED FOR FACING • Pins, Post and Cores • Bonded to metal – in case of porcelain • Mechanical inter locking – –under cut • –acrylic www.indiandentalacademy.com
  54. 54. 54 PRE TREATMENT ASSESMENT • PONTIC SPACE. • TISSUE CONTACT. • POSTINSERTION HYGIENE. www.indiandentalacademy.com
  55. 55. 55 PONTIC SPACE • One function of an FPDis to prevent tilting or drifting of the adjacent teeth into the edentulous space. • If such movement has already occurred, the space available forthe pontic may be reduced and its fabrication complicated. www.indiandentalacademy.com
  56. 56. 56 • At this point, creating an acceptable appearance without orthodontic repositioning of the abutment teeth is often impossible particularly if esthetic is important. • When orthodontic repositioning is not possible, increasing the proximal contours of the adjacent teeth may be betterthan making an FPDwith undersized pontics www.indiandentalacademy.com
  57. 57. 57 TISSUE CONTACT • The extent and shape of the pontic contact with the ridge is very important. • Excessive tissue contact has been cited as a majorfactorin the failure of fixed partial dentures. • The area of contact between the pontic and the ridge should be small and the portion of the pontic touching the ridge should be as convex as possible. www.indiandentalacademy.com
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  60. 60. 60 • If there is contact along the gingivofacial angle of the pontic, there must be no space between pontic and soft tissue on the facial side of the ridge. • If the tip of the pontic extends past the mucogingival junction, an ulcerwill form there. • The pontic should contact only attached keratinized gingiva www.indiandentalacademy.com
  61. 61. 61 Post insertion Hygiene • Mesial distal and lingual gingival embrasure of the pontic should be wide open to allow the patient easy access forcleaning • The contact between the pontic and tissue must allow the passage of floss from one retainerto the other • Good hygiene around and underthe pontic with dental floss, interproximal brushes or pipe cleaners. www.indiandentalacademy.com
  62. 62. 62 • Even the smoothest pontic surface must be cleaned well and often to prevent the accumulation of plaque. • If cleaning is not done at frequent, regular intervals, the tissue around the pontic will become inflamed. www.indiandentalacademy.com
  63. 63. 63 • Pontics designed forplacement in the appearance zone (areas of high visibility) must produce illusion of being teeth, esthetically, without compromising cleaning ability. • Those pontics placed in the nonappearance zone (usually mandibular posteriorreplacements) are there to restore function and prevent the drifting of teeth. www.indiandentalacademy.com
  64. 64. 64 Success of the FPD depends on the pontic design. www.indiandentalacademy.com
  65. 65. 65 • According to Eissmann, the boundaries of the edentulous space are the residual ridge, the opposing occlusal surface, the proximal surfaces of the abutment teeth, and the musculature of the tongue and cheek orlips. • The design consists of constructing a substitute tooth that favorably compares in form, function, and appearance with the tooth it replaces. www.indiandentalacademy.com
  66. 66. 66 Pontic Designs There are several designs available for use in situations requiring pontics in the fabrication of FPDs.They are: Hygienic, Saddle (Ridge Lap), Modified Ridge Lap, Conical, Ovate, Prefabricated Pontic Facings, & Metal- Ceramic Pontics. www.indiandentalacademy.com
  67. 67. 67 Sanitary or Hygienic Pontic • The term hygienic is used to describe pontics that have no contact with the edentulous ridge. • As its name implies, the primary design feature of the sanitary pontic allows easy cleaning, because its tissue surface remains clearof the residual ridge. www.indiandentalacademy.com
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  69. 69. 69 • This pontic design is frequently called a "sanitary pontic," which in years past was the trade name fora prefabricated, convex facing with’ a slot back, used formandibular molarpontics ' • This hygienic design permits easierplaque control by allowing gauze strips and other cleaning devices to be passed underthe pontic and seesawed in shoe-shine fashion. www.indiandentalacademy.com
  70. 70. 70 • The hygienic pontic is used in the nonappearance zone, particularly for replacing mandibularfirst molars. It restores occlusal function and stabilizes adjacent and opposing teeth. If there is no requirement foresthetics, it can be made entirely of metal. www.indiandentalacademy.com
  71. 71. 71 • The occlusogingival thickness of the pontic should be no less than 3.0 mm. and there should be adequate space underit to facilitate cleaning. The hygienic pontic is frequently made overall- convex configuration, faciolingually and mesiodistally 3mm www.indiandentalacademy.com
  72. 72. 72 • Making the undersurface of the pontic round without angles allows foreasier flossing. It is more difficult to get floss to pass overa flat undersurface evenly, orto get oversharp faciogingival and linguogingival line angles. The round design has been described as a “fish belly". www.indiandentalacademy.com
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  74. 74. 74 • Its disadvantages include entrapment of food particles, which may lead to tongue habits that may annoy the patient. • The hygienic pontic is the least "tooth like" design and is therefore reserved forteeth seldom displayed during function (i.e., the mandibularmolars). www.indiandentalacademy.com
  75. 75. 75 • An alternative design, in which the pontic is made in the form of a concave archway mesiodistally. The undersurface of the pontic is convex faciolingually, giving the tissue- facing surface of the pontic the configuration of a hyperbolic paraboloid. • There is added bulk forstrength in the connectors, and access forcleaning is good. An esthetic version of this pontic can be created by veneering with porcelain those parts of the pontic that are likely to bewww.indiandentalacademy.com
  76. 76. 76www.indiandentalacademy.com
  77. 77. 77 • This design has been called an “arc-fixed partial denture” a "modified sanitary pontic”, or simply a “Perel pontic”. www.indiandentalacademy.com
  78. 78. 78 SADDLE OR RIDGE LAP PONTIC • This pontic looks most like a tooth, replacing all the contours of the missing tooth. • It forms a large concave contact with the ridge, obliterating the facial, lingual, and proximal embrasures. www.indiandentalacademy.com
  79. 79. 79 • It is also called a ridge lap, because it overlaps the facial and lingual aspects of the ridge. • A contact with the ridge that extends beyond the midline of the edentulous ridge, ora sharp angle at the linguogingival aspect of the tissue contact, constitutes a ridge lap www.indiandentalacademy.com
  80. 80. 80 • This design has long been recognized as being unclean and uncleansable and it still is. • The saddle causes tissue inflammation, and it should not be used. • This design deficiency has been shown to result in tissue inflammation www.indiandentalacademy.com
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  83. 83. 83 MODIFIED RIDGE LAP PONTIC • The modified ridge lap pontic combines the best features of the hygienic and saddle pontic designs, combining esthetics with easy cleaning. • This design gives the illusion of a tooth, but it possesses all ornearly all convex surfaces forease of cleaning www.indiandentalacademy.com
  84. 84. 84 FPD partially seated FPD completely seated A :max, B:mand www.indiandentalacademy.com
  85. 85. 85 • The lingual surface should have a slight deflective contourto prevent food impaction and minimize plaque accumulation. • There may be a slight facio-lingual concavity on the facial side of the ridge, which can be cleaned and tolerated by the tissue as long as the tissue contact is narrow mesiodistally and faciolingually. www.indiandentalacademy.com
  86. 86. 86 • Ridge contact must extend no farther lingually than the midline of the edentulous ridge, even on posteriorteeth. • The contourof the-tissue-contacting area of the pontic should be convex, even if a small amount of soft tissue on the ridge must be surgically removed to facilitate it. www.indiandentalacademy.com
  87. 87. 87 •Tissue contact should resembleTissue contact should resemble a letterTwhose vertical arma letterTwhose vertical arm ends at the crest of the ridge.ends at the crest of the ridge. •This design was historicallyThis design was historically referred to as ridge-lap; the termreferred to as ridge-lap; the term ridge-lap is now usedridge-lap is now used synonymously with the saddlesynonymously with the saddle design.design. • The modified ridge lap designThe modified ridge lap design is the most common pontic formis the most common pontic form used in areas of the mouth thatused in areas of the mouth that are visible during function.are visible during function. www.indiandentalacademy.com
  88. 88. 88 • This design, with a porcelain veneer, is the most commonly used pontic design in the appearance zone forboth maxillary and mandibularfixed partial dentures www.indiandentalacademy.com
  89. 89. 89 CONICAL PONTIC • Often ,called egg-shaped, bullet-shaped, orheart- shaped, the conical pontic is easy forthe patient to keep it clean. • This pontic is related to the "sanitary dummy" described by Tinkerin 1918. • Its use is limited to replacement of teeth overthin ridges in the nonappearance zone. www.indiandentalacademy.com
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  91. 91. 91 • It should be made as convex as possible with only one point of contact at the centerof the residual ridge. • The conical pontic is rounded and cleanable, but the tip is small in relation to the overall size of the pontic. It is well suited foruse on a thin mandibularridge. www.indiandentalacademy.com
  92. 92. 92 • When used with a broad, flat ridge, the resulting large triangularembrasure spaces around the tissue contact have a tendency to collect debris. • This type of design may be unsuitable forbroad residual ridges, because the emergence profile associated with the small tissue contact point may create areas of food entrapment. www.indiandentalacademy.com
  93. 93. 93 A: correctly with a thin ridge B:incorrectly with broad flat ridge www.indiandentalacademy.com
  94. 94. 94 OVATE PONTIC • The ovate pontic is a round-end design currently in use where esthetics is a primary concern. • Its antecedent was the porcelain root- tipped pontic, which was used considerably before 1930-as an esthetic and sanitary substitute forthe saddle pontic. www.indiandentalacademy.com
  95. 95. 95 FPDpartially seated FPDcompletely seatedwww.indiandentalacademy.com
  96. 96. 96 • The ovate pontic is the most esthetically appealing pontic design. Its convex tissue surface resides in a soft tissue depression orhollow in the residual ridge, which makes it appearthat a tooth is literally emerging from the gingiva. • The tissue-contacting segment of the ovate pontic is bluntly rounded, and it is set into a concavity in the ridge. www.indiandentalacademy.com
  97. 97. 97 • The concavity can be created by placement of a provisional fixed partial denture with the pontic extending one-quarterof the way into the socket immediately afterextraction of the tooth. www.indiandentalacademy.com
  98. 98. 98 Advantage • It is easily flossed. • Its strength • Its pleasing appearance • In addition, its recessed form is not susceptible to food impaction. • The broad convex geometry is strongerthan that of the modified ridge lap pontic. www.indiandentalacademy.com
  99. 99. 99 Disadvantages • Because the tissue surface of the pontic is convex in all dimensions, it is accessible to dental floss; however, meticulous oral hygiene is necessary to prevent tissue inflammation resulting from the large area of tissue contact. • Otherdisadvantage include the need forsurgical tissue management. www.indiandentalacademy.com
  100. 100. 100 Prefabricated Pontic Facings • At one time, preformed porcelain facings were popularforfabricating pontics. • They required adaptation to a specific edentulous space, afterwhich they were reglazed. www.indiandentalacademy.com
  101. 101. 101 Slot back Reverse pin facing Harmony pin facing Tru- pontic Pontipwww.indiandentalacademy.com
  102. 102. 102 • Some, such as Trupontics, Sanitary pontics, and Steeles facings, relied on a lug in a custom cast metal backing to engage a slot in the occlusal orlingual surface of the facing • The large bulk of porcelain could result in a thin gold backing susceptible to flexing. www.indiandentalacademy.com
  103. 103. 103 • Harmony and Trubyte facings used horizontal pins that fit into the gold backing. • They were difficult to use in limited occlusogingival space, and refitting the pins into a backing aftercasting was demanding. www.indiandentalacademy.com
  104. 104. 104 • Porcelain denture teeth also were modified to use as pontic facings. Multiple pin holes, 2.0 mm deep, were made with a drill press in the lingual surface of the reverse pin facing. The pins came out of the backing, providing retention where a deep overbite would have overshortened conventional pins. • Unfortunately, the pin holes in the facing were stress points that led to fracture.www.indiandentalacademy.com
  105. 105. 105 PREFABRICATEDWAX PONTIC www.indiandentalacademy.com
  106. 106. 106 Metal-Ceramic Pontics • Most pontics are fabricated by the metal- ceramic technique. • With the widespread use of metal-ceramic restorations, metal- ceramic pontics have replaced othertypes of pontics employing porcelain. • Metal-ceramic pontics have the greatest esthetic potential as prosthetic replacements formissing teethwww.indiandentalacademy.com
  107. 107. 107 • A well fabricated metal-ceramic pontic is strong, easy to keep clean, and looks natural. • Additionally, metal-ceramic pontics are stronger, since the porcelain is bonded to the metal substrate ratherthan cemented to it. www.indiandentalacademy.com
  108. 108. 108 • Excessive thickness of porcelain contributes to inadequate support and predisposes to eventual fracture. • Sharp angles on the veneering area should be rounded. They produce increased stress concentrations that can cause mechanical failure www.indiandentalacademy.com
  109. 109. 109 • Any deformation of the metal frame work at the junction can lead to the chipping porcelain. • They are easierto use because the backing is custom made fora space (no need to adapt a premade porcelain facing to the space). www.indiandentalacademy.com
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  111. 111. 111 METAL CERAMIC • Advantages ► esthetics, biocompatible • Disadvantages ►weaker than all metal • Indication ► most situations • Contraindications ► long spans with high stresses www.indiandentalacademy.com
  112. 112. 112 All metal • Advantages ►strength,easy procedure • Disadvantages ► non esthetic • Indication ► mandibular molars • Contraindications ► where esthetics is important www.indiandentalacademy.com
  113. 113. 113 Fiber reinforced all resin • Advantages ► Conservative, esthetics, ease of repair • Disadvantages ► Limited to short span • Indications ► High esthetic concern • Contra indications ► Long span FPDs www.indiandentalacademy.com
  114. 114. 114 Saddle/ridge lap • Location ►Not recommended • Advantages ►Esthetics • Disadvantages ►Poor oral hygiene • Indications ►Not recommended • Contra indications ►Not recommended • Materials ►Not applicable www.indiandentalacademy.com
  115. 115. 115 Sanitary/hygienic • Location ►Posterior mandible • Advantages ►Good access for oral hygiene • Disadvantages ► Poor esthetics • Indications ►Non esthetics zones& impaired oral hygiene • Contra indications ►Where esthetic is important • Materials ►All metalwww.indiandentalacademy.com
  116. 116. 116 Modified ridge lap • Location ►High esthetic • Advantages ►Good esthetics • Disadvantages ►Moderately easy to clean • Indications ►Area with esthetic concern • Contra indications ►Where minimal esthetic concern • Materials ►Metal ceramic and all resin www.indiandentalacademy.com
  117. 117. 117 Conical • Location • Advantages • Disadvantages • Indications • Contra indications • Materials ► Molars without esthetics ► Good accesses For oral hygie ► Poor esthetics ► Posteriors ► Poor oral hygiene ► All metals ,metal ceramics, all resin www.indiandentalacademy.com
  118. 118. 118 Ovate • Location ► Maxillary anteriors • Advantages ► Superior esthetics, ease of cleaning • Disadvantages ► Requires surgical preparation • Indications ► Optimal esthetics, high smile line • Contra indications ► Un willingness for surgery • Materials ► Metal ceramic, all resins www.indiandentalacademy.com
  119. 119. 119 Conclusion • Principles of pontic designing is the primary concern • In posterior segment where esthetics is not critical, a sanitary pontic form is most compatible with function and hygiene • In the maxillary anterior region – modified ridge lap pontic design constructed of glazed porcelain readily fulfills both esthetic and physiologic requirements • Role of oral hygiene measures plays a vital role • Patient should be highly motivated and instructed www.indiandentalacademy.com
  120. 120. 120 Referances • DCNA Comprehensive fixed prosthodontics vol. 36 1992 • Tylman, Theory and practice of fixed prosthodontics 8th edition • Rosenstiel, contemporary fixed prosthodontics, 3rd edn, • Shillingberg, fundementals of fixed prosthodontics, 3rd edn., • JPD vol.28, 1972 • JPD vol.16, 1966 • Quintessence Int 2002 • JPD vol.46, 1981 • J.oral Rehabil 1996 • JPD vol.88, 2002 • IJP vol.9, 1996 • J Prosthodont, vol.11, 2002www.indiandentalacademy.com
  121. 121. www.indiandentalacademy.com 121

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