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Veneers/ fixed orthodontics courses


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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.

Veneers/ fixed orthodontics courses

  1. 1. GOOD MORNING INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. A captivating smile showing an even row of natural gleaming white teeth is a major factor in achieving that elusive dominant characteristic known as personality. This entails lack of an inferiority complex due to crooked, unsightly teeth, which during speech causes a hand to be raised to cover the mouth or manipulation of the lips in an unnatural manner to make up for the defect. It is this lack of confidence in dental equipment which often spells the difference in success and failure
  3. 3. VENEERS
  4. 4.
  6. 6. • INDIRECT VENEERS – Processed composite – Porcelain laminate veneers – Cast ceramic laminate system – Veneers for metal restoration – Veneers for existing metal restoration • REPAIR OF VENEERS • CONCLUSION • MY VIEWS • BIBLIOGRAPHY
  7. 7. INTRODUCTION The demand for the tooth color restorations and a more attractive smile has now passed the boundaries of exclusive practitioners, specialist and the esthetic centers all over the world. As esthetically pleasing restorations of young fractured malformed or discolored teeth has been a perplexing problem for dentist, in past few years a conservative approach to improve the esthetic appearance has led widespread use of the veneering systems. An idea of covering the unattractive teeth is not new it goes back to many decades to the original "Hollywood bridge" and to more recent porcelain laminate veneers.
  8. 8. HISTORY
  9. 9. It is an out growth of the process described by Dr.Charles Pinicus in 193029 . At that time it was only for the temporary esthetic modification and for the improvement of smile of Hollywood film actresses. The concept of laminate veneers although existing long back, got surface in 1975 by Rochette29 who introduced the use of silane coupling agent with porcelain laminate veneers of repairing fractured incisors. Then the popularity of porcelain laminate skyrocketed in 1980's partly because of its conservative nature and the dental researches in the acid etched technique and new bonding
  10. 10. Porcelain has long history in the dental field. It is one of the most esthetically suitable and biocompatible material available. Porcelain abrasion and stain resistance are excellent and well tolerated by gingival tissues. Thus it makes porcelain laminate veneers superior to other veneering systems. Porcelain laminate veneer restoration has a unique position in today's dental practice. Increase awareness of veneers and their potential has sparked the numerous technical variations and there has been lot of improvement regarding the technical and in the material aspects.
  11. 11. REVIEW OF LITERATURE • Highton Ren, Angeco A.Caputo and Joska Matyas (1987)4 concluded from the photo elastic study on four design for tooth preparation for porcelain laminate veneer that incisal, labial, proximal and gingival reduction is recommended for patients with class I division I malocclusion. Although modification of variant tooth condition may be necessary, gingival tooth preparation was essential to control stress distribution and provide the best potential for periodontal health.
  12. 12. • Graber A.David (1989)2 compared direct composite' veneer versus etched porcelain laminate veneers. He concluded that inherent weakness in composite veneer was in the composite itself. The etched porcelain restoration offered the advantage of increased strength, color, stability and biocompatibility for veneering material using composite merely as a luting agent. He further concluded that the etched porcelain restoration, in future, will replace direct bonding composite restoration most clinical situation. • Tjan M.L., Anthony et al (1989)26 evaluated the micro leakage of conventional porcelain and Dicor castable ceramic laminate veneer bonded either entirely on acid etched enamel or with cervical margin on
  13. 13. Light cure composite resin cement system were used to lute the veneers. They concluded that, there was minimal micro leakage under both type of ceramic veneer bonded to all enamel preparation and markedly greater leakage at the dentine composite resin interface in veneer with cervical margins placed on dentine.
  14. 14. • Herbert Victor Exner (1991)20 investigated the predictability of color (hue, value and chroma) on cervical surfaces, body surfaces and incisal surfaces of ceramic veneers and the extent to which laminates may be shade adapted by use of tints and opaquers on the fitting surfaces. In his study he found significant discrepancies in the final color match of ceramic laminate veneers. He concluded that dentist should opt for a lighter, more translucent shade, which can be modified before final cementation.
  15. 15. • Magne Pascal et al (1999)8 investigated the parameters associated with the development of cracks in porcelain veneers using cyclic thermal fatigue. This study points out the importance of a controlled and uniform tooth reduction. A minimal and homogenous thickness of ceramic will provide the restoration with a favorable tooth configuration. For enamel surfaces, it was essential to establish the original volume of the tooth. Use of an additive diagnostic wax up and corresponding silicon matrices are imperative. During laboratory procedures, die spacer should be applied carefully to avoid an excessive luting composite thickness at a particular location.
  16. 16. • Hekimoglu Canan, Nesrin Anrl and IIker Etikan (2000)19 studied the effect of accelerated aging on the color stability of cemented laminate veneers. This study investigated the effect of in vitro accelerated aging of different durations on the color properties of dual cure, light cure and self cure resin cements. They concluded that, overall color change, chroma change, and hue change of the materials tested were not influenced by prolonged aging time. Overall color change was not affected by type of cementing material. Chroma change and hue change were influenced by the type of cementing material. They also proposed light cure resin cement as a suitable material for luting laminate
  17. 17. • Jacopo Castelnuovo, Anthony H. L. Tjan Dr Dent, Keith Phillips, Jack I. Nicholls, John C. Kois (2000)22 did an in vitro study to evaluate fracture load and mode of failure of ceramic veneers, with 4 tooth preparation designs, that were bonded on extracted human maxillary central incisors. Identical parameters were also measured on unrestored intact teeth for comparison. Each group was assigned a different tooth preparation design: (1) no incisal reduction, (2) 2 mm incisal reduction without palatal chamfer (butt joint), (3) 1 mm incisal reduction and 1 mm height palatal chamfer, (4) 4 mm incisal reduction and 1 mm height palatal chamfer, and (5) unrestored (control). Groups 1 and 2 recorded the greatest fracture loads that were comparable to an unrestored control.
  18. 18. • Hager BertH, Agneta Oden, Bernt Anderson et al (2001)18 the use of Procera All Ceram laminates for patients with discolored teeth has been described. In their experience, these laminates are simple to use and provide possibilities for excellent esthetics. • George P. Cherukara, Graham R. Davis, Kevin G.Seymour, Lifong Zou, DayanandaY.D.Samarawickrama (2005)17 did a study to assess the effectiveness of 3 clinical techniques, namely, dimple, depth groove, and freehand, in producing an intraenamel preparation. The relation between overpreparation beyond the commonly accepted depth of preparation of 0.5 mm and dentin exposure was also examined.
  19. 19. • A single operator prepared 3 groups of 5 extracted maxillary central incisors to a depth of 0.5 mm using dimple, depth-groove, and freehand methods of tooth preparation. The prepared teeth were scanned using an x-ray microtomography scanner. Within the limitations of this pilot study, the 3 different techniques tested did not differ significantly in conserving enamel.
  20. 20. • Seok-Hwan Cho, DDS Won-Gun Chang, DDS, Bum-Soon Lim, Yong-Keun Lee (2006)28 did a study to evaluate the shear bond strength differences between enamel and a feldspathic PLV as a function of die spacer thickness. It was found that the appropriate application of die spacer exerts a favorable influence on the shear bond strength of composite-bonded PLV. The 2-coat application of die spacer provides suitable space to accommodate the cement thickness.
  21. 21. • Fernando Zarone, Ettore Epifania, Giuliana Leone, Roberto Sorrentino, Marco Ferrari, MD, (2006)16 The purpose of this study was to detect the stress in maxillary anterior teeth restored with porcelain veneers and compare the resistance to fracture of porcelain veneers prepared using different preparation designs. The SEM analysis showed that both adhesive and cohesive fractures were primarily concentrated at the cervical region. Statistical analysis showed that both the type of tooth and the design of the preparation significantly influenced the resistance to fracture of the restored teeth (P<.001).
  22. 22. The chamfer preparation is recommended for central incisors, whereas the window preparation showed better results for canines. Both preparations can be adopted in the restoration of lateral incisors.
  23. 23. DEFINATIONS • Complete Crown / Full Veneer Crown: A restoration that covers the entire coronal tooth surfaces (mesial, distal, facial, lingual and occlusal)26 • Veneers : A thin sheet of material usually used as a finish protective or ornamental facing26 • Laminate Veneers : A superficial or attractive display in multiple layers26 • Partial Veneer Crown: A restoration that restores all but one coronal surface of a tooth or dental implant abutment, usually not covering the facial surface26
  24. 24. The art of veneering teeth has progressed over 30 years to the current generation or concepts and materials. Typically veneers are made of chair side composite, processed composite, porcelain, or cast ceramic material. Veneers can be divided into two categories: I. Directly fabricated composite resin veneers (i.e. free hand placed), and 2. Indirectly fabricated veneers, such as preformed laminates or laboratory fabricated acrylic resin, micro fill resin, or porcelain veneers.
  25. 25. DIRECT VENEERS • Buonocore's12 research of the acid etch technique in 1955, combined with Bowen's later use of filled resins, provided the technology enabling mechanical bonding between etched tooth and filled resins (direct bonding). Although these were major breakthroughs in dental research by the early 1960s, little esthetic use was made of this bonding technology of nearly a decade. This was partially due to the limitations of the available self curing resins, which did not allow sufficient working time for the dentist to recreate a labial surface before the composite resin chemically cured itself.
  26. 26. • The introduction of light cured composite resins in the early to mid 1970s allowed the dentist greater flexibility. The advantages of visible light cured composite resins, such as greater working time and improved chemistry, versus the self cured composite resins, marked the entrey into the next generation of esthetic materials. Visible light cured composite resins were replacing self cured composite resins by the late 1970s and were preferred for esthetic anterior restorations. • Direct acid etched bonding proved to be advantageous, yet a susceptibility to stain, poor wear resistance, and lack of natural fluorescence spurred the continued search for improved materials.
  27. 27. INDIRECT VENEERS The idea of restoring teeth for esthetic purposes became more widely accepted by the dental community as new esthetic restorative techniques and material became available. Faunce12 described a one piece acrylic resin prefabricated veneer as an improved alternative to direct acid etched bonding. By using a chemical primer applied to the veneer and a composite to lute the veneer onto an etched tooth both a chemical and mechanical bond contributed to the attachment. It was more stain resistant than composite resin veneers, but numerous preformed acrylic resin laminates suffered from de lamination at the laminate/composite interface, usually due to the weak chemical
  28. 28. • Like composite resins, they also exhibited poor resistance to abrasion. The inherent advantage to laboratory fabricated veneers is the anatomical accuracy. Laboratory formed acrylic resin veneers and laboratory fabricated microfiIl resin veneers offer a smooth surface, good masking ability, and very little finishing, if they are completed properly. However, their esthetics, strength, and longevity can be surpassed by porcelain laminates. Veneers are also classified as: 1. Partial Veneers And 2. Full Veneers
  29. 29. • Partial veneers are indicated for the restoration of localized defects or areas of intrinsic discoloration. Full veneers are indicated for the restoration of generalized defect or areas of intrinsic staining involving the majority of the facial surface of the tooth.
  30. 30. • Full veneers can be accomplished by a direct or an indirect technique. When a small number of teeth are involved or when the entire facial surface is not faulty (partial veneers), directly applied composite veneers can be completed for the patient in one appointment with chair side composite. . Placing direct composite full veneers is very time consuming and labor intensive. However, for cases involving young children, a single discolored tooth, or when economics or patient time are limited precluding a laboratory fabricated veneer, the direct technique is a viable option.
  31. 31. Advantages of indirect technique: • Much less technique sensitive to operator ability. • Second, if multiple teeth are to be veneered, indirect veneers usually can be placed much more expeditiously. • Third, indirect veneers typically will last much longer than a indirect veneer, especially if made of porcelain or cast ceramic.
  32. 32. • Some operators prefer to etch the existing enamel and apply the veneer over the entire existing facial surface without any tooth preparation. • The perceived advantage of this method is, that in case of failure or in the event the patient does not like the veneer, it can be removed, thus being reversible. • However, several significant problems exist with this approach: 1. First, in order to achieve an esthetic result, the facial surface of such a restoration must be over contoured, thus appearing and feeling unnatural. Hyperemia and bleeding due to bulbous and impinging gingival contours.
  33. 33. 2. Second, the veneer is more likely to be dislodged when no tooth structure is removed before the etching and bonding procedures are done. If the veneer is lost, it can be replaced, but the patient may live in constant fear that it will happen again, possibly creating an embarrassing situation. Removing full veneers with no damage to the underlying unprepared tooth is exceedingly difficult if not impossible.
  35. 35. • To consistently achieve esthetic and physiologically sound results, an intraenamel preparation is almost always indicated. The only exception is in cases where the facial aspect of the tooth is significantly under contoured due to severe abrasion or erosion. In these cases, mere roughening of the involved enamel and defining of the peripheral margins are indicated.
  36. 36. • Intraenamel preparation (or the roughening of the surface in under contoured areas) before placing a veneer is strongly recommended for the following reasons; (l) To provide space for opaque, tinting, bonding and/or veneering materials for maximal esthetics without over contouring; (2) To remove the outer fluoride rich, layer of enamel which may be more resistant to acid etching; (3) To create a rough surface for improved bonding; and (4) To establish a definite finish
  38. 38. The only logical reason for; extending the margin sub gingivaIly is if the area is carious or defective, warranting restoration, or if it involves significantly dark discoloration that presents a difficult esthetic problem.
  39. 39.
  40. 40. PREPARATION DESIGN FOR FULL VENEER: Two basic preparation designs exist; (I) a "window" preparation, and (2) An incisal lapping preparation.
  41. 41.
  42. 42.
  43. 43. • A "window" preparation is recommended for most direct and indirect composite veneers. This intraenamel preparation design preserves the functional lingual and incisal surfaces of the maxillary anterior teeth, protecting the veneers from significant occlusal stress. A "window" preparation design also is recommended for indirectly fabricated porcelain veneers if the patient exhibits significant occlusal function as evidenced by wear facets on the lingual and incisal surfaces. By using a "window" preparation, the functional surfaces are better preserved in enamel. This design reduces the potential for accelerated wear of the opposing tooth that could result if the functional path involved porcelain on the lingual and incisal surfaces,' as with an incisal lapping design.
  44. 44. • Incisal lapping preparation is indicated when the tooth being veneered needs lengthening or when an incisal defect warrant restoration. Additionally, the incisal lapping design is frequently used with porcelain veneers, because it not only facilitates accurate searing of the veneer upon cementation, but also allows for improved esthetics along the incisal edge. • The preparation and restoration of a tooth with a veneer should be carried out in a manner that will provide optimal function, esthetics, retention, physiological contours, and longevity. All of these objectives should be accomplished without compromising the strength of the remaining tooth structure.
  45. 45. • Discolored mandibular anterior teeth are rarely indicated for veneers, because the facio incisal portions are thin and usually subject to biting forces and attrition. Therefore, veneering lower teeth is discouraged if the teeth are in normal occlusal contact, because it is exceedingly difficult to achieve adequate reduction of the enamel to totally compensate for the thickness of the veneering material. Also, if porcelain veneers are placed, they may accelerate wear of the opposing maxillary teeth because of the abrasive nature of the porcelain.
  46. 46. DIRECT VENEERS TECHNIQUE: • Teeth are cleaned and isolated • The "window' preparation is typically made to a depth roughly equivalent to half the thickness of the facial enamel ranging from approximately 0.5 to .75 mm midfacially and tapering down to a depth of about 0.2 to 0.5 mm along the gingival margin, depending on the thickness of enamel. A heavy chamfer at the level of the gingival crest provides a definite cavity margin for subsequent finishing procedures: The margins are not extended subgingivally
  47. 47. • The preparation for a direct veneer normally is terminated just facial to the proximal contact except in the area of a diastema. To correct the diastema, the preparations are extended from the facial onto the mesial surfaces, terminating at the mesio lingual line angles. The incisal edges are not included in the preparations • The teeth should be restored one at a time. After etching, rinsing, and drying procedures apply and polymerize the resin bonding agent. Place the composite on the tooth in increments, especially along the gingival margin, to reduce the effects of polymerization shrinkage. Place the composite in slight excess to allow some freedom in contouring. It is helpful to inspect the facial surface from an incisal view with a mirror to evaluate the contour before polymerization.
  48. 48. • Tetracycline-stained teeth are much more difficult to veneer, especially if dark banding occurs in the gingival third of the tooth. • Margins are placed subgingivally. May indicate (along with other possible indications) local anesthesia. • Shade selection is more difficult. The posterior teeth usually have a more normal shade and can often be used as a guide. • To obtain a natural appearance, it is helpful to make the cervical third of the teeth one shade darker than the middle or incisal areas. Additionally, the canines should be one shade darker than the premolars and incisors.
  49. 49. INDIRECT VENEER TECHNIQUES: Many dentists find that the preparation, insertion, and finishing of several direct veneers at one time is too difficult, fatiguing, and time consuming. Some patients become uncomfortable and restless during long appointments. Also, veneer shades and contours can be better controlled when made outside of the mouth on a cast. For these reasons, indirect veneer techniques are usually preferable. Indirect veneers include those made of (1) processed composite (2) feldspathic porcelain3 , and (3) cast ceramic6 . Because of superior strength, durability and esthetics, feldspathic porcelain and cast ceramic are by far the most popular materials for indirect veneering techniques used by
  50. 50. • Cast ceramic veneers offer comparable qualities, but require exacting laboratory technique and allow only limited chair side finishing and alteration of contours; however, excellent laboratory support and the superb marginal fit of these veneers can minimize or eliminate this disadvantage. Although two appointments are required for indirect veneers, chair time is saved because much of the work is done in the laboratory. Excellent result can be obtained when proper clinical evaluation and careful operating procedures are followed. Indirect veneers are attached to the enamel by acid etching and bonding with either a self cured, light cured, or dual cured resin bonding material.
  51. 51. PROCESSED COMPOSITE VENEERS: • Composite veneers can be processed in a laboratory to achieve superior properties. Using intense light, heat, vacuum, pressure, or a combination of these, cured composites can be produced which posses improved physical and mechanical properties compared to traditional chair side composites. Additionally, indirectly fabricated composite veneers offer superior shading and characterizing potential as well a better control of facial contours. Because their composition is similar to chair side composite, indirect composite veneers are capable of being bonded to the tooth with a resin bonding medium. After acid etching, bonding agent is applied to the etched enamel as with any composite restoration. A fluid resin bonding medium then is used to bond the veneer in place.
  52. 52. • A chemical bond is formed between the bonding agent and the bonding medium and to a lesser extent, between the bonding medium and the processed composite veneer. Excellent mechanical retention occurs at the interface of the bonding medium and tooth from the roughened tooth surface resulting from preparation with a coarse diamond instrument as well as from tag formation into the etched enamel. • Most processed composites presently are micro fill composites. Although significant advantages exist over direct composite veneers, indirect veneers made of processed micro fill composites possess limited bond strength because of the reduced potential to form a chemical bond with the bonding medium. Consequently, they should not be used in areas of high occlusal stress.
  53. 53. • A newly developed processed composite of the hybrid type, filled with barium glass and colloidal silica, offers a significant improvement in bond strength. Because this type of composite contains particles of barium glass, relatively soft radiopaque filler, it can be sandblasted and etched in the laboratory with a mild concentration (9% to 10%) of hydrofluoric acid to produce numerous areas of microscopic undercuts, similar to the phenomenon that occurs when enamel is etched. By producing a surface capable of micromechanical bonding, "Etched composite veneers (Herculite XR V Lab) of this type can be strongly bonded to enamel without relying on significant chemical bonding.
  54. 54. • Processed composite veneers are easily placed, finished, and polished. They also can be replaced or repaired easily with chair side composite. For these reasons, indirect processed composite veneers are often recommended for placement in children and adolescents as interim restorations until the teeth have fully erupted and achieved their complete clinical crown length. At that time, usually at age 18 to 20 years, a more permanent alternative such porcelain or castable ceramic veneers can be pursued. • Indirect processed composite veneers also are indicated for placement in patients who exhibit significant wear of their anterior teeth due to occlusal stress.
  55. 55. • However, only the "'etched composite" type of veneers are recommended in cases of occlusal stress because of their superior bond strength. Because of their lower cost, indirect processed composite veneers also offer an esthetic, affordable alternative to more costly porcelain or castable ceramic types when economic is the primary consideration. However, it must be pointed out to the patient that processed composite veneers typically do not exhibit comparable clinical longevity.
  56. 56. PORCELAIN LAMINATE VENEERS: • Glazed porcelain has a long history of use in dentistry as one of the most esthetic and biocompatible materials available, surpassed only by enamel itself. Porcelain's abrasion and stain resistance are excellent and it is well tolerated by gingival tissues. The advent of porcelain labial veneers as a permanent esthetic restoration marked the progression of more than 30 years of dental research in acid etch, bonding, and esthetic restorative techniques. The concept of acid etching porcelain was cited in the dental literature in 1975 when Rochette described the innovative restoration of a fracture incisor with an “etched silanted porcelain block”.
  57. 57. • Essential to the attachment of porcelain veneers is the ability of porcelain to be etched and bonded to composite resin and to exhibit a high tensile bond strength, as reported by Simonsen and Calamia. Continued research by Calamia and Simonsen also showed that treatment of the etched porcelain veneer with a silane coupling agent produced a chemical bond that enhanced the porcelain/composite resin mechanical bond7 . • Although relatively technique sensitive, the surface texture, color, fluorescence, and overall esthetics of porcelain laminate veneers have been regarded as exceptional. In addition, the ability to adjust final color during placement allows maximum flexibility in final shade
  58. 58. • A recent major break through that facilitated predictable retention of porcelain to the tooth surface has added a new dimension to esthetic dentistry. Porcelain veneers can be considered to be very much the "state-of-the-art" in cosmetic dentistry because they offer innumerable advantages over any previous form of veneering system. • Horn R.Harold3 stated that porcelain veneering system is a new modality for oral repair and it is important to understand the art and science inherent in its accomplishment as it will bring rewards in the conservative dental health. • Grabes A.David2 stated that etched porcelain restoration, in future, will replace direct bonding composite restoration is most clinical
  59. 59. ADVANTAGES OF PORCELAIN LAMINATES: • Color • Bond strength • Periodontal health • Resistance to abrasion • Resistance to Fluid Absorption • Esthetics
  60. 60. DISADVANTAGES OF PORCELAIN LAMINATES: • Time • Repair • Color • Tooth preparation • Fragility • Cost
  61. 61. INDICATIONS: • Discoloration • Enamel defects • Diastema • Malpositioned teeth
  62. 62. • Malocclusion • Poor restorations • Aging • Wear patterns • Agenesis of the lateral incisor
  63. 63. CONTRAINDICATIONS : • Available enamel • Ability to etch enamel • Oral Habits • The System's Inherent Strength
  64. 64. • Gilmour A.S.M. and Stone D.C.19 stated that careful treatment planning and patient selection is necessary to avoid problems and to ensure that the best result was achieved with porcelain veneers.
  65. 65. • Although processed dental porcelain has a high compressive strength, it is completely non-ductile and therefore brittle. Also, because of surface irregularities inherent in the manufacturing process, dental porcelain restorations have a low tensile strength. These surface irregularities, even though microscopic in size, can cause significant stress concentration. In the non-ductile porcelain, stresses cannot be relied by plastic deformation (as is possible in metals) and even minor defects under tensile stresses may develop into larger cracks by a mechanism of crack propagation. Ultimately, the process may cause additional stress concentration and failure in the form of a brittle
  66. 66. GOOD
  68. 68. • INDIRECT VENEERS – Processed composite – Porcelain laminate veneers – Cast ceramic laminate system – Veneers for metal restoration – Veneers for existing metal restoration • REPAIR OF VENEERS • CONCLUSION • MY VIEWS • BIBLIOGRAPHY
  69. 69. METHODS OF STRENGTHENING PORCELAIN: • Because of the inherent weakness of dental porcelain, different methods to strengthening it have been developed. The porcelain fused to metal restoration is probably the most well known example for a porcelain strengthening system and allow porcelain to be effectively used in dental restorations. The metal structure provides, in addition to accurate fit, a mechanism to prevent porcelain failure under tensile stresses. Other commonly used porcelain reinforcing methods are metallic foil substructures, the aluminous porcelain core, and the more recently introduced magnesia -alumina spinel.
  70. 70. 1.Etched Porcelain: This new treatment modality employs the fine etching of the porcelain inner surface both for retention and porcelain reinforcement. With resin bonding of etched porcelain to tooth, part of the clinical success can be explained by the polymerization shrinkage of the resin (a property inherent in most polymers) which stresses the thin porcelain in a direction that reduces the chance of crack formation and propagation. The retentive qualities of the porcelain surface may well depend upon the nature of the microscopic pattern produced during the etching process.
  71. 71. • Etching the porcelain surface with hydrofluoric acid (or a derivative) produces the microscopic surface roughness that provides retention when combined with a flowing resin capable of polymerizing. Early etching methods for porcelain consisted of either a 15 minute etch with a 10% hydrofluoric acid or 20 minute etch with a commercial preparation consisting primarily of diluted hydrofluoric acid. Initial bond strength values based on these etching methods were reported to be around 1,100 psi.
  72. 72. The Effects of Solution and Time on Etching: • The combination of porcelain etching with a silane bonding promoter seems to have a cumulative effect that maximizes the bond strength significantly. The value of 3,500 psi for the group combining porcelain etching and silane pretreatment is far better than bond strengths obtained in early experiments. This bond also surpasses the resin enamel bond strength. • In the non etched porcelain groups a gap existed between the porcelain and resin that was most probably produced by the polymerization contraction of the resin. The silane treatment caused a narrowing of the gap, apparently as a result of improved chemical attraction.
  73. 73. • In the etched porcelain, silane - treated groups no gap was found, and the resin seemed to have filled all the porcelain defects. Apparently, the rough etched surface treated with silane produced a surface attraction, causing the resin to wet it well. The good adaptation of resin to etched porcelain seems to have produced the highest bond strengths. • The studies have also established that the etching of the porcelain is the cardinal element in obtaining good retention with the resin. Thus the combined etching and silane treatment produced the highest bond strengths.
  74. 74. 2. Polymerization: • Complete polymerization of the composite resin is another essential requirement for obtaining a good bond between the tooth and porcelain. Polymerization of light activated composite resins is dependent on the transmission of light and its penetration through the porcelain into the composite resin. Several factors can affect this light transmission, but most important are the thickness of the porcelain and its opacity, and the opacity of the composite resin used.
  75. 75. • Systems with a dual polymerization initiation system (photo and chemical curing) give a significantly better bond strength with thick porcelain than do systems that polymerize solely by light. Visible light polymerization shows a substantial reduction in effectiveness when the light has to travel through more than 3 mm of porcelain. • The subject of resin polymerization is extremely important because retention and mechanical support to the brittle porcelain restorations are a direct function of the degree of polymerization. Incomplete polymerization reduces bond strength significantly, and may contribute to early clinical separation and failure.
  76. 76. • The phenomenon of incomplete polymerization is more likely to occur in thick etched porcelain restorations, such as inlays or onlays, where the thickness of porcelain may approach 4 to 8 mm in some areas. In the thin anterior porcelain veneers, this is less likely to occur because the light can easily penetrate through 0.5 to 1 mm of porcelain. However, in interproximal regions where the light rays might enter at an angle to the porcelain surface, the degree of penetration and degree of polymerization may be reduced. In both thin and thick etched porcelain restorations, immediate retention will not be affected because some thin sections probably exist that will allow full setting of the resin in those
  77. 77. • The restoration will therefore appear secure in place, but it may contain much unreacted resin that could eventually wash out and cause marginal caries. Longevity of Porcelain Restorations: • Etched porcelain restorations are not subject to surface wear, roughness, or discoloration, as may be the case with some direct composite resins. However, longevity of these restorations is dependent primarily on the bond strength between the restoration and the underlying dental tissue. A weak resin to porcelain bond (or deterioration of the bond with time) will cause early failure of the restoration by subjecting it to the possibility of deformation fracture.
  78. 78. • Hui K.K.K., B.Williams, E.H.Davis5 stated that window type of preparation was the strongest when compared with overlapped or feathered, design. • Highton Ren et al4 stated that gingival tooth preparation is essential to control stress distribution and provide the best potential or periodontal health. • Magne Pascal et al8 pointed out the importance of controlled and uniform tooth reduction.
  79. 79. Material: • Pippin David, James M.Mixon and Anton P., Soldon- Els10 stated that porcelain veneers appeared to be clinically acceptable, durable restoration for maxillary anterior teeth. • There are different opinions regarding the type of tooth preparation porcelain laminate veneers requires. Some clinicians believe that little or no tooth reduction is required, whereas others, at the opposite end of the spectrum, advocate a full, deep chamfer preparation on the labial aspect of the teeth and most or all of the way through the interproximal contact areas.
  80. 80. The decision of whether to reduce enamel should depend on the following biological and technical factors: • Esthetics • Relative tooth position • Masking of tetracycline stain • Marginal placement • Age • Psychology • The potential for periodontal changes • Plaque removal The amount of enamel reduction necessary, based on the needs, is in the realm of 0.3 to 0.6 mm or about half the thickness of available enamel
  81. 81.
  82. 82. ENAMEL REDUCTION PROCEDURE: 1. Labial Reduction: • The labial preparation should encompass the amount of reduction necessary to facilitate the placement of an esthetic restoration. Ideally, one would like to replace the same amount of enamel that is removed by the' preparation. However, in certain situations, such as rotated teeth or teeth in I labial version, it may be advantageous to first bring the offending teeth into, alignment with the rest of the arch by reducing their labial contour. • There may be situations where in small areas, to facilitate cosmetic alignment, some amount of dentin will be exposed by the preparation of the tooth. This is not that critical if it is limited to only small areas and the margins remain on
  83. 83. • Dental bonding, however, provides only a fraction of the bond strength possible with enamel bonding and a less effective seal. Therefore, a good general rule may well be to ensure that over 50% of the preparation is on enameL A problem with fresh dentin exposure is the potential of the acidic etching solution and the bonding material itself to cause pulpal hyperemia or even necrosis.
  84. 84. 2.Depth Guide: • The depth cutting diamond comes in two sizes (laminate Veneer System (L VS) No.1 and L VS No.2) one of which would be appropriate for the tooth to be prepared. These dimensions are 0.5 mm reduction foremost situations and 0.3 mm for small teeth such as mandibular incisors where the thickness of enamel is considerably less.
  85. 85.
  86. 86. Reduction of the Remaining Enamel: The labial reduction should encompass two aspects I. The bulk of the reduction should be done with a coarse diamond in order to facilitate added retention and better refraction of the light being transmitted back out through the laminate and 2. At the marginal area, it is desirable to use a fine grit diamond that will create a definitive, smooth finish line to enhance the seal at the periphery.
  87. 87. • Move the diamond across the labial surface from a mesial to distal direction, following the curvature of the gingiva from the top of the mesial inter proximal papillae down to the most apical extent of the free gingival margin and back up to then tip of the distal inter proximal papillae. The finish line should be right at the gingival margin in most instances. • Depending on the path of insertion, it may be necessary to remove some extra tooth substance to facilitate a path of insertion from the incisal edge toward the cervical margin. If, however, the veneer does not lap the incisal edge it can be placed from the buccal direction, and removal of all convexities will not be as critical.
  88. 88. 3. Inter proximal Extension: The margin of the porcelain laminate should generally be hidden within the embrasure area. Depending on the individual form of the tooth, it is usually desirable to extend this margin about half way into the inter proximal contact area. Extension of the laminate beyond the mesio buccal and disto buccal line angle also ensures the wraparound effect with etched resin bonds at right angles to the labial surface for increased bond strength
  89. 89. Proximal seat without breaking contactProximal seat without breaking contact
  90. 90. 4. Dentin Exposure: • Dentin may be exposed during tooth preparation when dealing with a labially placed tooth that needs to be brought back into harmonious alignment with the rest of the arch. A rotated tooth poses similar problems, as does the clinical situation in which there has been gingival recession when the preparation extends apically beyond the cemento enamel junction onto exposed cementum or dentin. If the dentinal area exposed is surrounded by enamel to provide a peripheral marginal seal, it can be managed with a dentin bonding agent. This may be a conventional dentin bonding agent, a phosphorous ester of the BIS- GMA molecule, or one of the newer systems such as the aluminium oxalates or
  91. 91. • If the dentin exposure occurs at the periphery, such as the cervical region, it is advisable to prepare a little deeper into this area so that a layer of glass ionomer can be used as a base. This glass ionomer base will bond to the dentin and seal it. • During the enamel etching procedures use a gel form of the acid and confine it solely to the enamel. If in doubt cover the dentin with a film of dentin bonding agent to seal it prior to acid etching.
  92. 92. 5. Sulcular Extension and Marginal Placement: At this stage the preparation ends right at the gingival margin. It is, however, desirable to place it just within the sulcus. Place a narrow gingival displacement cord in the sulcus for about eight to ten minutes to slightly displace the tissue. This system of first developing a preparation line confluent with the gingival margin. and then placing a retraction cord prior to refining and extending it into the sulcus ensures: I. Access for the diamond. 2. Less gingival trauma
  93. 93.
  94. 94. • Because of the tissue displacement, this refined margin will appear to supra gingival until the effect of the astringent wears off. This preparation remains a considerable distance from the biologic width so there is little potential for violating it and developing untoward gingival reactions. 6. Finish Line Configuration: A feather or knife edge finish line is the most conservative preparation but is inordinately complex because of: 1. The difficulty in fabricating porcelain to the required degree of thinness accurately and there is invariably a poor marginal fit or
  95. 95. 2. The invariable increased thickness subgingivally and resultant potential for gingival problems. 3. Laboratory problems in delineating the exact end of preparation line. • It would appear that the most desired form of finish line is a modified chamfer of nominal depth (±0.25 mm) near the cemento enamel junction. The preparation of a chamfer in this cervical area aids in sealing the restoration by removing the acid resistant surface enamel and exposing subsurface enamel which is more readily
  96. 96. Benefits of the Modified Chamfer Finish Line: 1.An increased bulk of porcelain at the margin and hence increased strength without over contour. 2. Correct enamel preparation exposing correctly aligned enamel rods for increased bond strength at the cervical margin. 3. A well defined finish line for the laboratory yet without too great a potential for porcelain sintering shrinkage - increased accuracy of fit. 4. Greater ease for the dentist to obtain a correct gingival finish line after insertion. 5. A definitive stop to aid in seating the laminate in the correct position on the tooth.
  97. 97. 7. Incisal or Occlusal Reduction: The fabrication of a porcelain veneer lapping the incisal edge makes : 1. Placement of the restoration that much easier by virtue of having a definitive stop during seating. 2. Gives the clinician a specific relationship from which to evaluate whether the restoration is correctly positioned. 3. The preparation should be a definitive flattening of the incisal edge to create increased enamel width and potential bonding surface for the laminate. 4. The sharp line angles created on the buccal and lingual surfaces must be rounded, however, which will again increase the surface area of enamel and prevent the propagation of microcracks in the porcelain.
  98. 98.
  99. 99. • The reduction should be at least 1 mm if it is desired to restore the original length. If the incisal edge is not to be included it is still useful to increase the amount of horizontal tooth reduction at the periphery of the preparation, the inter proximal areas, and the incisal edge. • In general, never end the incisal edge where excursive movements of the mandible will cause shearing stresses across the junction of porcelain laminate and tooth. This potentiates fracture of the porcelain, de bonding, and ongoing exposure of the composite resin in this crucial area.
  100. 100. • The incisal preparation design is somewhat controversial. Gilmour and Stone19 and Glyde and Gilmour19 have classified the preparation of this site into four types. They are; I. Window or intraenamel preparation labially with intact incisal enamel (results in an inferior appearance). 2. Feathered incisal preparation labially (porcelain is prone to fracture) 3. Incisal edge preparation of 0.5 to 1.0 mm tooth reduction incisally (if no tooth lengthening needed) to form a butt joint lingually, and . 4. Incisal edge preparation as in 3, but overlapped onto the lingual surface by using a heavy chamfer preparation the most
  101. 101. Freedman and Mc Laughlin classified the preparation into six basic types: Type 1 : Minimal Preparation Type 2 : Incisal Preparation
  102. 102. Type 4 : Over The Incisal Edge With A Lingual Ledge Type 3 : Over The Incisal Edge
  103. 103. 8. Lingual Reduction: Any reduction of the incisal edge may necessitate some lingual enamel modification so that there is no butt joint at this incisal I lingual junction but rather a rounded chamfer. This modification will help to prevent the porcelain from shearing away from the incisal edge during function. It also ensures: 1. Increased thickness of porcelain in this critical lingual area that is being used for incising and guidance. 2. Enamel bonds at right angles to those on the incisal edge, and 3. Increased
  104. 104. Impression
  105. 105.
  106. 106.
  107. 107. ETCHING
  108. 108. • Place the labial surface of the veneer on a clay strip, allowing the concave inner aspect of the veneer to act as receptacle. Then fill the interface of the veneer with the etching gel (e.g. 7.5% hydrofluoric acid) and allow it to stand for seven to ten minutes. The gel must occasionally be brushed up to the margins to ensure etching in this critical area. Different porcelain systems require different etching times with various etching mediums. Individual manufacturer's instructions must be followed for optimum results.
  109. 109. • When the etching phase is completed, lift the entire clay strip by both edges and completely submerge the veneers in a 10% solution of baking soda and water until the acid is neutralized. The gel will bubble and rise to the surface of the solution. Remove the veneer from the solution and dry. Air abrade the interface until it is free of etched ceramic debris. • Clean the veneers in a detergent solution in an ultrasonic bath for three minutes each and dry with an oil free air syringe or a jet of warm air. Prior to the final luting of the porcelain veneers, It is important to go through a try-in stage, which is a three phase process:
  110. 110. 1. The intimate adaptation of each individual porcelain laminate to the prepared tooth surface must be checked. 2. The collective fit and relationship of one laminate to another and the contact points need to be evaluated. 3. The color needs to be assessed and, if necessary, modified. • Stage 1 : Check for Individual Fit: • Stage 2 : Collective Fit Try-In: • Stage 3 : Color Check: Exner Victer Herbert stated that dentist should opt for a lighter, more translucent shade, which can be modified before final cementation.
  111. 111. Luting Agents: Desirable Features for Luting l1aterial : • Thin film thickness, 10 to 20 micrometers • High compressive strength • High tensile strength • Relatively low viscosity • Ability to opaque • Low polymerization shrinkage • Color stability
  112. 112.
  113. 113. Veneer Placement Procedure: 1. Tissue management: 2. Layout: 3. Silantation : The silane bond enhancer may be preactivated and hydrolyzed or it may need to be activated with an acid. A preactivated silane is painted onto the etched porcelain surface and allowed to dry for about one minute. The excess alcohol vehicle is then gently evaporated by passing a stream of air parallel to and approximately 6 inch above the surface of the laminate. This will leave a dry, silane coated veneer. 4. Enamel Activation: 5. Isolation: 6. Enamel etching:
  114. 114. • The tooth is isolated on both sides by placing either mylar strips or a matrix band mesially and distally. The tooth is etched with 30% to 37% phosphoric acid solution for 15 to 20 seconds. The etchant must reach the very periphery of the preparation where a seal is highly critical to the long term success of the restoration. Gingival displacement is important to expose this margin and prevent contamination. The etching material (gel or liquid) is washed from the enamel surfaces with copious amounts of water for a full 30 seconds. • Do not let the patient rinse or in any way contaminate this etched enamel surface with saliva. If this occurs the surface must be re-etched for ten seconds, washed, and dried again to redevelop a reactive enamel surface.
  115. 115. • Application of dental bonding agent: Again isolate the underlying etched tooth surface with matrix strips and oat it with a combined enamel dental bonding agent of the light activated type, which is gently air dispersed into a thin, even layer. All excess bonding agent must be gently blown aside. Light cure this evenly dispersed layer to seal the tooth surface. • Next coat the internal aspect of the veneer (which has been silanated) with an unfilled resin bonding liquid: blow it into a thin layer but do not light cure it. Place the composite resin luting agent on the laminate, using some form of syringe and express the material into the center so that it spreads laterally, without trapping air bubbles.
  116. 116. • Seating sequence: It is best to seat one laminate at a time. In multi unit cases, start with the distal most tooth on each side of the arch and work mesially to the canine. Next seat the two central incisors simultaneously to ensure that they match. The two lateral incisors are then seated one at a time, to accommodate any discrepancies in overall fit. • Placement: Rotate the veneer onto the buccal surface of the tooth and then gently manipulate it until contact is made in the region of the gingival finish line. The motion must be a gently rocking or "pulsing" motion that slowly allows the excess material to escape from all sides of the veneer. The gross excess may be removed with a firm, pointed paintbrush or a curette. It is important not to slide the veneer into
  117. 117. • Passing it over the incisal edge may wipe the internal aspect of the veneer clean of the composite resin, leaving a void. This can be prevented by rotating it about the incisal edge into place. Hold the laminate firmly in position to prevent "suck-back" and begin the polymerization process with the light unit. • During the curing process, it is essential to maintain complete stability of the relationship between the veneer and the underlying tooth. The polymerization process is completed by curing the various areas of the veneer for at least two minutes each. This extra time is important due to the fact that the light has to travel through the porcelain to reach the underlying composite resin.
  118. 118. 10. Curing: • Time: • Angle of Contact: • Shade of the resin: • Composite resin composition: • Distance: II. Finishing: 12. Occlusal Assessment: 13. Cosmetic Contouring:
  119. 119.
  120. 120.
  121. 121.
  122. 122. INSTRUCTIONS TO THE PATIENTS FIRST 72 HOURS : • The resin bonding process takes at least 72 hours to cure in its entirety. During this time, one should avoid any hard foods and maintain a relatively soft diet. Extremes in temperature (either hot or cold) should also be avoided. Alcohol and some medicated mouth washes have the potential to affect the resin bonding material during this early phase and should not be used. MAINTENANCE: • Routine cleaning are a must, at least every four months with a hygienist, who should avoid using an ultrasonic scaler and the air abrasion
  123. 123. • Use a soft tooth brush with rounded bristles and floss as one does with natural teeth. If daily cleaning of plaque is a problem, use a mechanical plaque removal device, because plaque free maintenance of these restorations is essential to their longevity and the health of teeth and supportive tissues. • Use a less abrasive tooth paste and one that is not highly fluoridated. Although laminate are strong, avoid excessive biting forces and habit patterns; nail biting, pencil chewing etc. • A void biting into hard pieces of candy, chewing on ice, etc. • Use a soft acrylic mouth guard when involve in any form of contact sport.
  124. 124. MOUTH RINSES: • Acidulated fluoridated mouth rinses can damage the surface finish of laminates and should be avoided. Chlorhexidine antiplaque mouthrinses may stain laminates, but the stain can be readily removed by a hygienist.
  125. 125. CAST CERAMIC LAMINATE SYSTEM • Easy to fabricate since it uses the familiar lost wax method of processing • More translucent than alumina based core material • Stronger than feldspathic porcelain • Can be built to full contour and shade stained or coping made and layered with porcelain • More translucent than alumina based core material
  126. 126. • Marginal fit very good similar to metal casting • Can be etched with hydrofluoric acid so bonding with resin most reliable • Aesthetics excellent because of translucency similar to natural enamel • Has good record of clinical success.
  127. 127. VENEERS FOR METAL RESTORATIONS : • Esthetic inserts (partial or full veneer) of a tooth colored material can be placed on the facial surface of a tooth previously restored with a metal restoration. For new castings, plans are made at the time of cavity preparation and during laboratory development of the wax pattern to incorporate a veneer into the cast restoration.
  128. 128. VENEERS FOR EXISTING METAL RESTORATIONS: Occasionally the facial portion of an existing metal restoration (amalgam or gold) is judged to be distracting. A careful examination, including a radiograph, is required to determine that the existing restoration is sound before an esthetic correction is made. The size of the offensive area determines the extent of the preparation. Anesthesia is not usually required, since most of the preparation is in metal or enamel.
  129. 129. • Preliminary procedures • A No.2 carbide bur rotating at high speed with an air water spray is used to remove the metal, starting at a point midway between the gingival and occlusal margins. The preparation is made perpendicular to the surface approximately 1 mm deep at a minimum, leaving a butt joint at the cavosurface margins. The 1 mm depth and a butt joint should be maintained as the preparation is extended occlusally. All of the metal along the facial enamel is removed, and the preparation is extend into the facial and occlusal embrasures just enough for the veneer to hide the metal. The contact areas on the proximal or occlusal surfaces must not be included in the preparation. To complete the outline form, the preparation is extended gingivally approximately 1 mm past the mark indicating the clinical level of the gingival
  130. 130.
  131. 131. • The final cavity preparation should have the same features as those for veneers is new cast restorations. Mechanical retention is placed in the gingival area with a No. 1/4 carbide bur (air coolant to enhance vision) 0.25 mm deep along the gingivo axial and linguo axial angles. Retention and esthetics are enhanced by beveling the enamel cavosurface margin (bevel approximately 0.5 mm wide) with the coarse, flame shaped diamond instrument oriented at 45 degrees to the external tooth surface. After it is etched, rinsed, and dried, the cavity preparation is complete. New adhesive resin lines containing a chemical called 4- MET A, capable of bonding composite to metal, also may be used but are quite technique sensitive. The composite material is inserted and finished in the usual manner.
  132. 132.
  133. 133. REPAIR OF VENEERS • Failures of esthetic veneers occur because of breakage, discoloration, or wear. Consideration should be given to conservative repairs of veneers if examination reveals that the remaining tooth and restoration are sound. It is not always necessary to remove all of the old restoration. The material most commonly used for making repairs is light cued composite. • Veneers on tooth structure: Small chipped areas on veneers can often be corrected by re contouring and polishing. When a sizable area is broken, it can usually be repaired if the remaining portion is sound.
  134. 134.
  135. 135. • Indirect processed composite veneers are repaired in a similar manner. However, in order to repair porcelain veneers, a mild hydrofluoric acid preparation, suitable for intraoral use, must be used to etch the fractured porcelain. Hydrofluoric acid gels are available in approximately 10% buffered concentrations which are intended for intraoral porcelain repairs. Although caution still must be taken when using hydrofluoric acid gels intraorally, the lower acid concentration allows for relatively safe intraoral use. • A lightly frosted appearance, similar to that of etched enamel, should. be seen if the porcelain has been properly etched. A silane coupling agent may be applied to the etched porcelain surface prior to the application of the resin bonding agent. Chair side composite material is then added, cured, and finished
  136. 136. FAULTY VENEERS IN METAL RESTORATIONS : • The teeth are cleaned with a slurry of pumice and the shade selected before isolation by cotton rolls and retraction cords • All of the old resin material is removed with an appropriate instrument such as a No.1558 carbide metal cutting bur. • Should endeavor to create a chamfered finish line. Retention is placed with a No.33 carbide bur in selected areas in the metal along the line angles approximately 0.25 mm deep.
  137. 137. • It is usually better to place the veneers one at a time. A light cured composite is recommended because of the extended working time. The preparation is cleaned with acid etchant for 30 seconds, then rinsed and dried to remove debris and obtain a clean, dry surface. • A masking material (opaquing resin) is artfully placed with a small brush over the metal areas of the preparation by applying and curing successive thin layers. These materials should be placed directly over the prepared metal surface. Next, a small amount of composite material (gingival shade) is placed at I the cervical area with a hand instrument, adapted with the tine of a No.2 I explorer, and cured with visible light. New material of the pre selected lighter shade is added to restore the middle and incisal
  138. 138.
  139. 139.
  140. 140. CONCLUSION • New emerging concepts in esthetic dentistry with regards to materials, technology and public awareness has made veneers on demand. It has been less than a decade since the phenomenon of fusing porcelain directly to tooth was first described in 1980's since then the growth and development in this field has been nothing short of humungous. Yet because the science is still in its infancy caution is required. The average dentist has a tendency to think only in terms of articulation also and function with a little thought to esthetics.
  141. 141. We should always keep in mind that we are dealing with organs, which can change an individuals entire visual personality. A captivating smile showing an even row of natural gleaming white teeth is a major factor in achieving that elusive dominant characteristic called personality. The objective of cosmetic dentistry must be to provide the maximum improvement in esthetic with the minimum trauma to the dentition. There are a number of procedure that begin in approximate the ideal parameter of cosmetic dentistry, most notably that of porcelain laminate veneers.
  142. 142. MY VIEWS Lot of propagation of various dental products regarding the porcelain laminate veneer with each heralding to be more esthetically pleasant, stronger, better and requiring less lab work and insertion steps, force us to "quantum expansion of dental knowledge of porcelain laminate veneering system" . Perfect smile improves the self confidence, personality; social life and have psychological effect on improving self image with enhanced self esteem of the patient.
  143. 143. • Improvement of smile makes us gratifying and opens door in the new dimension of dental treatment using veneers. As we are in the new era of resin bonded porcelain (ceramic and esthetic dentistry), this seminar has tried to enlighten and emphasize upon newer information regarding materials, methods and techniques regarding veneers.
  144. 144. BIBLIOGRAPHY 1. Alastair C.McLundie 1991 : "Localised palatal tooth surface loss and its treatment with porcelain laminates". Restorative Dentistry. 2. Graber A.David 1989: "Direct composite veneers versus etched porcelain laminate veneers". DCNA. Vo1.33 (2),301-304. 3. Harold Horn R. 1983 : “Porcelain laminate veneers bonded to etched enamel.” Dent Clin North Am. 27 : 671-684. 4. Highton Ren et al 1987 : "A photoelastic study of stresses on porcelain laminate preparations'. JPD. Vol.58 (2), 257-260. 5. Hui K.K.K., Williams B., Davis E.H. and Holt R.D. 1991 : "A comparative assessment of the strength of porcelain veneers for incisor teeth dependent on their design characteristics". Br J Dent. 50-55.
  145. 145. 6. Lang S.A., Starr C.B. : Castable glass ceramics for veneer restorations. J Prosthet Dent. 67 (5) : 590-594. 7.Kenneth Anusavice J. 1996: "Philips' Science of Dental materials". W.B.Saunders Co., Philadelphia, 10tb Edition, 510. 8.Magne Pascal et al1999 : "Crack propensity of porcelain laminate veneers - A simulated operatory evaluation". JPD. 81,327-334. 9.Nathanson Stangel D. and Hsu C.S. 1987 : "'Shear strength of the composite bond to etched porcelain". J Dent Res. 66 (9), 1460-1465. 10.Pippin David J., James M. Mixson and Anton P. Solan Els 1995 :"Clinical evaluation of restored maxillary incisors : Veneers vs PFM crowns". J Am Dent Assoc. 126, 1523-1528. 11.Sterling Ronk L. 1981 : "Dental Lamiantes, which technique?" JADA. Vol. 102, 186-188.
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  148. 148. 20.Herbert Victor Exner 1991 : "Predictability of color matching and the possibilities for enhancement of ceramic laminate veneers". JPD. 65, 619-622. 21.Ibsen Robert L. 1986 : "An innovative method for fixed anterior tooth replacement utilizing porcelain veneers' . Vol. 17 (7),455-459. Quintessence International. 22.Jacopo Castelnuovo et al 2000 : Fracture load and mode of failure of ceramic veneers with different preparations. J Prosthet Dent 83:171-80. 23.Rada Robert E. and Betty Jean Jankowski 1991 : "Porcelain laminate veneer provisionalization using visible light curing acrylic resin". Quintessence Int. 22, 291-293.
  149. 149. 24.Switft E.J. et al 1992 : Treatment of composite surfaces for indirect bonding, Dent Mater. 8 : 193- 196. 25.Tay W.M., Lynch E.and Auger D. 1987 : "Effects of some finishing techniques on cervical margins of porcelain laminates". Quintessence International. 18 (9), 598-603. 26.Tjan Anthony H.L. et al 1989 : "microleakage patterns of porcelain and castable ceramic laminate veneers". JPD. Vol.61, 276-282. 27.Glossary of Prosthodontic Terms. J Prosthet Dent 1999; 81: 41-110. 28. Seok-Hwan Cho,Won-Gun Chang,Bum-Soon Lim,Yong-Keun Lee 2006: Effect of die spacer thickness on shear bond strength of porcelain laminate veneers. 95:3
  150. 150. 29. David A Garber, Ronald E Goldstein, Ronald E Feinman: Porcelain Laminate Veneers. 30.George A Freedman, Gerald L. McLaughlin: Color Atlas Of Porcelain Laminate Veneers.
  151. 151.