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Selection of restorative materials
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- 2. SELECTION OF RESTORATIVE MATERIALS GUIDEDBY:- DR. MANJU PRESENTED BY:- CHARUL SAINI P.G. 1ST YEAR 2
- 3. CONTENTS Introduction Factors regulating selection Significanceof good selection Materials related factors Tooth related factors Patient related factors Restorative materials Conclusion 3
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- 5. The practice ofclinical dentistry depends not only on a complete understanding of the various clinical techniques but also on an appreciation of the fundamental biological, chemical, and physical principles that support the clinical applications. Reciprocally, the higher surface energy of many restorative materials compared with that of the tooth surface could result in a greater tendency for the surface and margins of the restoration to accumulate debris, saliva, and bacteria. Craigs 13th edition ,International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 5
- 6. Some restorative materialsare more sensitive to technique variations than others. For example, placement of resin composite restorations in posterior teeth requires more steps than for an amalgam. There are numerous factors to be considered when restoring a tooth, eg. the extent of lesion, the strength of the remaining tooth structure, the preference of the dentist in using the material, and the financial cost of the procedure and tooth related factors. Craigs 13th edition ,International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 6
- 7. Clinical expertise thereforeis an important factor when developing a treatment plan and selecting restorative materials, particularly when the restoration is a direct application to the tooth. Although it is important to know the comparative values of properties of different restorative materials, it is also essential to know the quality of the supporting and investing hard and soft tissues. Craigs 13th edition ,International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 7
- 8. Factors regulating Selection • Teethneed restorative intervention most commonly due to carious destruction. • This must be accomplished with; Restoration of proper form, function, esthetics, and occlusal stability. International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 8
- 9. Significance of goodselection Restoration of carious teeth presents the dentist with the dilemma of selecting a suitable restorative material. Dentist must make this selection with great care because, in future years, those restorations needing replacement will result in the loss of increasing amount of tooth structure. This setup a cycle where the increasing cavity size limits the choice of the materials that may be used effectively. International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 9
- 10. Material- related Factors The idealrestorative material should- Resist occlusal forces Resist the wear Indestructible in oral fluids Adequately adapted to the cavity walls Co-efficient of thermal expansion should be comparable to tooth structure Exhibit low thermal conductivity International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 10
- 11. Biocompatible Accomplished with minimal tooth preparation Strengthen the remaining toothstructure Antibacterial Esthetically pleasing Compatible with the pulpal and periodontal health Easily manipulated International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 11
- 12. Tooth – related Factors Characteristicsof the Carious Lesion • The choice of restorative material depends upon the tooth type, its location in the arch, forces acting on the tooth, the surface(s) to be restored, and lesion depth. • If anterior tooth is involved then choice is made among esthetic materials, in case posterior tooth is involved, then material with high strength is used. International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 12
- 13. Status of thePulp If there is no threat to the health of the pulp by carious lesion, caries is removed avoiding pulpal exposure and then restore the tooth with permanent restoration. Pulp capping is performed in the teeth with questionable condition. If pulp is irreversibly involved, then endodontic treatment is done. International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 13
- 14. Size of the Periodontium Theoperative procedure must be performed only after evaluating the health status of the periodontium. International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 14
- 15. Size, Form andStructure of Teeth • When open proximal contacts are to be restored, reestablishment of the space or slight alteration in the usual size of the tooth is to be decided. • Recontouring of interproximal surfaces is usually done with cast gold or metal ceramic restorations, as they have greater convenience and accuracy, as these are made by indirect method. • Amalgam often fails to close the contact and produce an ideal interproximal contour due to its physical properties, technique of placement and condensation. International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 15
- 16. Patient- related Factors Ageof the patient Physical condition of the patient Hygienic condition of the mouth Strength and character of the bite Expense of the operation Bruxism International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 16
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- 19. It has beenan accepted part of dental therapeutics for more than 150 yrs. It is still used for more than 75% of direct posterior restorations today. Amalgam is a metallic material which is composed of- Mixture of mercury + powdered alloy(Ag, Sn, Zn, Cu) This mixture is –Amalgam alloy. Marzouk 1st edition, Vimal K Sikri 4th edition 19
- 20. Clinical considerations Along the margins ofthe amalgam corrosion products help to seal the space against microleakage. Compressive strength of high copper amalgams is greater than low copper amalgams Marzouk 1st edition, Vimal K Sikri 4th edition 20
- 21. High copper amalgams havea clinical longevity of 24-25 years. The average replacement age of conventional (low copper) amalgams in clinical practice is 5-8 years. ▪ Amalgam is a brittle material. Traumatic stresses during chewing can produce fracture in an amalgam without sufficient bulk. Marzouk 1st edition, Vimal K Sikri 4th edition 21
- 22. Extrusion at marginsis promoted by electrochemical corrosion, during which mercury from Sn-Hg re-reacts with Ag-Sn particles and produces further expansion during the new reaction -mercuroscopic expansion resulting in marginal fracture. The most common evidence of degradation of low copper amalgams is marginal fracture. High copper amalgams display only modest marginal fracture over long periods. ▪ An amalgam restoration done in a tooth with the opposing tooth having a gold inlay may result in sharp pain due to development of galvanic currents. Marzouk 1st edition, Vimal K Sikri 4th edition 22
- 23. Advantages of amalgamrestorations over other direct-placement materials include - resistance to wear; - tolerance to a wide range of clinical placement conditions especially wet fields - excellent load-bearing properties - clinical longevity - greater radiopacity - ability to seal the marginal gap space over time Marzouk 1st edition, Vimal K Sikri 4th edition 23
- 24. They can conduct thermalshocks to the pulp They may flow and deform the restorations. They have objectionable metallic color. Vimal K Sikri 4th edition 24
- 25. INDICATIONS Class I and classII cavities (moderate to large restorations). Restorations with heavy occlusal forces. Restorati ons that can’t be well isolated. Resin veneer over amalga m Class III in unaestheic areas (eg- distal aspect of canine especially; if preparation is extensive with minimal facial involvement). In class V, where non- esthetic areas especially; when access is limited & moisture control is difficult & for significantly deep gingival areas. Marzouk 1st edition, Vimal K Sikri 4th edition 25
- 26. Contraindications ▪ Prominent estheticareas of the mouth. ▪ Because the tooth preparation for amalgam is larger than for a composite, most small to large defects in posterior teeth should be restored with composite rather than amalgam. ▪ Small Class VI restorations Marzouk 1st edition, Vimal K Sikri 4th edition 26
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- 28. Glass-ionomers are materials consistingof ion-cross-linked polymer matrices surrounding glass-reinforcing filler particles. Formulated in 1970s by bringing together the silicate and polyacrylate systems. Applications Luting agents Orthodontic bracket adhesives Pit and fissure sealants Liners and bases Core build-ups Intermediate restorations Restoration of eroded areas Craigs 13th edition ,Marzouk 1st edition, Vimal K Sikri 4th edition 28
- 29. Advantages ▪ Easy mixing ▪Leachable fluoride and caries preventive potential ▪ Adhesion to tooth structure Marzouk 1st edition, Vimal K Sikri 4th edition 29
- 30. Clinical considerations ▪ Well suitedfor situations involving high caries risks. ▪ When bonding composite to gingival areas with little or no enamel, a GIC liner extended just short of the margins has been suggested as a way to reduce caries risk if microleakage occurs. ▪ Low fracture toughness - recommended principally for non-stress-bearing areas, e.g., carious and non-carious cervical lesions and approximal anterior lesions. Marzouk 1st edition, Vimal K Sikri 4th edition 30
- 31. GICs have alow modulus of elasticity -counter forces at the cervical of the tooth that might otherwise disrupt the bond. ▪ Pediatric restorations - service longevity requirements are low. ▪ Role in minimal intervention dentistry. For small proximal caries lesions, the tunnel preparation and GI- fillings were recommended in 1984. Advantages include small cavity preparations, preservation of marginal ridge and proximal contact Marzouk 1st edition, Vimal K Sikri 4th edition 31
- 32. Contraindications • ▪ Instress bearing areas. • ▪ Labial build ups • ▪ Cuspal coverage Vimal K Sikri 4th edition 32
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- 34. Indications Class I, II, III,IV, V & VI restorations . Indications for Class I and II: – small and moderate restorations preferably with enamel margins – most premolars or first molars where esthetics is important – some large restorations -to strengthen remaining weakened tooth structure ( for economic or interim use reasons) Marzouk 1st edition, Vimal K Sikri 4th edition 34
- 35. Foundations and corebuild-ups ▪ Sealants and preventive resin restorations. ▪ Esthetic enhancement procedures – veneers, tooth color modifications, diastema closure. ▪ Cements for indirect restorations ▪ Temporary restorations ▪ Periodontal splinting Marzouk 1st edition, Vimal K Sikri 4th edition 35
- 36. Contraindic ations ▪ An operating areathat cannot be adequately isolated ▪ Patients with heavy occlusion, bruxism, or restorations that provide all of the tooth contacts ▪ Class V restorations that are not aesthetically critical ▪ Restorations that extend onto the root surface. A V-shaped gap is formed between the root and the composite because polymerization shrinkage of the composite is greater than the initial bond strength of the composite to root dentin. Marzouk 1st edition, Vimal K Sikri 4th edition 36
- 37. Advantage: ▪ Esthetic ▪ Conservativeof tooth structure removal. ▪ Less complex when preparing tooth. ▪ Insulative, having low thermal conductivity. ▪ Used almost universally. ▪ Bonded to tooth structure, resulting in good retention, low microleakage, minimal interfacial staining, and increased strength of remaining tooth structure. ▪ Repairable Marzouk 1st edition, Vimal K Sikri 4th edition 37
- 38. Disadvantage: • ▪ Theyhave low wear resistance. • ▪ Their adaptation to the surrounding walls may be destroyed easy due to their polymerization contraction and their relative high co-efficient of thermal expansion. • ▪ Are more technique sensitive Marzouk 1st edition, Vimal K Sikri 4th edition 38
- 39. INDIRECT COMPOSITE INLAY Teethcan be restored using indirect techniques, in which restorations are fabricated outside the mouth. Most indirect restorations are made on a replica of the prepared tooth in a dental laboratory by a trained technician. Marzouk 1st edition, Vimal K Sikri 4th edition 39
- 40. INDICATIONS Esthetics Large defects or previous restorations Forimprovement in contacts and contours Vimal K Sikri 4th edition 40
- 41. CONTRAINDICATIONS Heavy occlusal force Inabilityto maintain a dry field Deep subgingival preparations Vimal K Sikri 4th edition 41
- 42. Indirect tooth-colored restorativematerials are more durable than direct composites, especially in regard to maintaining occlusal surfaces and occlusal contacts. Indirect restorations have better physical properties than direct composite restorations because they are fabricated under relatively ideal laboratory conditions. Reduced polymerization shrinkage Marzouk 1st edition, Vimal K Sikri 4th edition 42
- 43. DISADVANTAGE Difficulty in resin toresin bonding Low potential for repair Vimal K Sikri 4th edition 43
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- 45. Dental ceramics arenon-metallic inorganic structures, primarily containing compounds of oxygen with one or more metallic or semi-metallic elements Vimal K Sikri 4th edition 45
- 46. ADVANTAGE: ▪ Esthetics ▪ Biocompatibility ▪Insulation ▪ Wear resistance ▪ Can be formed into precise shapes ▪ Can be bonded to tooth structure Vimal K Sikri 4th edition 46
- 47. DISADVANTAGE ▪ Brittleness ▪ Technique sensitive ▪High cost ▪ Difficult to repair intraorally. Vimal K Sikri 4th edition 47
- 48. Metal ceramics Materials for metal-ceramic restorationscontain a vitreous phase, also called glassy matrix, that represents 75 to 85% by volume and are reinforced by various crystalline phases. ▪ The choice of the crystalline phase in compositions for metal-ceramic restorations was initially dictated by the need for matching the thermal contraction coefficient of the porcelain close to that of the metallic infrastructure in order to avoid the development of tensile stresses within the porcelain when cooled. Marzouk 1st edition, Vimal K Sikri 4th edition 48
- 49. ▪ Less toothstructure needs to be removed compared to all ceramic prostheses especially if metal only is used on occlusal and lingual surfaces. ▪ Advantages are permanent aesthetic quality of a properly designed reinforced ceramic unit and their resistance to fracture. Clinical considerations Marzouk 1st edition, Vimal K Sikri 4th edition 49
- 50. A Metal ceramiccrown is not the best aesthetic choice for an anterior crown. Metal-ceramic FPDs should be considered first as choice for posterior FPDs. Only when the patient is highly resistant to accepting metallic components during treatment should all- ceramic FPDS be considered for posterior sites. Marzouk 1st edition, Vimal K Sikri 4th edition 50
- 51. ALL CERAMIC Materials for all-ceramicrestorations use a wider variety of crystalline phases as reinforcing agents and contain up to 90% by volume of crystalline phase. Nature, amount, and particle size distribution of the crystalline phase directly influence the mechanical and optical properties of the material. Vimal K Sikri 4th edition 51
- 52. Advantages: • – Lowshrinkage due to high molecular wt. • – Good abrasion resistance • – Fluoride release • – Good esthetics . • – Condensable • – Biocompatible Vimal K Sikri 4th edition 52
- 53. Uses: – Fillings inanterior and posterior regions Vimal K Sikri 4th edition 53
- 54. CEROMERS Ceramic optimized polymer(lightcured) Advantages: – Good wear resistance – Good strength – Adhesive bonding – Fluoride release (Tetric Ceram) Vimal K Sikri 4th edition 54
- 55. – Needs complete isolation –Cannot be used in very high stress regions – Preferably supragingival margins Vimal K Sikri 4th edition 55
- 56. Uses: – Posterior bridge with singlepontic – Implant superstructures – Fillings Vimal K Sikri 4th edition 56
- 57. An inlay isan indirect restoration (filling) consisting of a solid substance fitted into a cavity in a tooth between cusps and cemented into place. An inlay is an indirect restoration that caps none or one or more cusps but not all Vimal K Sikri 4th edition 57 CERAMIC INLAY
- 58. • Ceramic inlayspermit preservation of much coronal tissue. • They can be used in lieu of a metal-casting or amalgam restoration in patients who require a class II restoration. • They are stronger than direct posterior composite resins, offering superior physical properties than the latter, as the degree of polymerization conversion of direct posterior composites limits their strength INDICATIONS Vimal K Sikri 4th edition 58
- 59. CONTRAINDICATIONS Areas where heavy occlusal forces are present Inabilityto maintain a dry field Cases involving deep subgingival preparations In the presence of an unfavorable occlusion, a group-function occlusal arrangement, or in patients exhibiting evidence of parafunctional activity such as bruxism or clenching. Marzouk 1st edition, Vimal K Sikri 4thedition 59
- 60. ADVANTAGE Wear resistance: Ceramic restorationsare more wear resistant than direct composite restorations Biocompatibility and good tissue response: Ceramics are considered chemically inert materials with excellent biocompatibility and soft tissue response Vimal K Sikri 4th edition 60
- 61. DISADVANTAGE Technique sensitive Brittleness of Ceramics Wear of opposing dentitionand restorations Low potential for repair Vimal K Sikri 4th edition 61
- 62. It is anindirect restoration that caps all cusps (combination of intracoronal and extracoronal restoration). Sturdevant’s Art And Science Of Operative Dentistry Fifth Edition 62 CERAMIC ONLAY
- 63. Materials used forindirect restorations ; classified in to Esthetic ( composite /ceramics) Non esthetic (metal) Sturdevant’s Art And Science Of Operative Dentistry Fifth Edition 63
- 64. Among ceramic materialsused include feldspathic porcelain, hot pressed ceramics and machinable ceramics designed for use with CAD/CAM systems. They have excellent wear resistance and coefficient of thermal expansion close to tooth structure. Sturdevant’s Art And Science Of Operative Dentistry Fifth Edition 64
- 65. INDICATIONS Esthetics Large defects or previous restorations Economic factors CONTRAINDICATIONS Heavy occlusal forces Inability to maintaina dry field Deep subgingival preparation s Sturdevant’s Art And Science Of Operative Dentistry Fifth Edition 65
- 66. ADVANTAGES Improved physical properties Varietyof materials and techniques Wear resistance Reduced polymerization shrinkage Ability to strengthen remaining tooth structure More precise control of contour and contact Biocompatibility and good tissue response Sturdevant’s Art And Science Of Operative Dentistry Fifth Edition 66
- 67. DISADVANTAGES Increased cost andtime Technique sensitive Brittleness of ceramics Wear of opposing dentition and restorations Short clinical track record Low potential for repair Difficult try in and delivery Sturdevant’s Art And Science Of Operative Dentistry Fifth Edition 67
- 68. VENEERS A well-defined protocolfor the treatment of complex esthetic cases with the use of ceramic veneers has become a modern tool to mask the unpleasant smile. A veneer is a layer of tooth-colored material that is applied to a tooth to restore localized or generalized defects and intrinsic discolorations. Sturdevant’s Art and science of operative dentistry (fifth edition) 68
- 69. Partial veneers areindicated for the restoration of localized defects or areas of intrinsic discoloration Full veneers are indicated for the restoration of generalized defects or areas of intrinsic staining involving the majority of the facial surface of the tooth Sturdevant’s Art and science of operative dentistry (fifth edition) 69
- 70. INDICATIONS For treatment ofdiscolored teeth that do not respond to tooth-whitening or micro- abrasion procedures The closure of interdental spacing and restoration of malformed teeth where crowns are not indicated Realignment of in-standing, rotated or protruding teeth Discrepancies in the size and shape of teeth that are not correctable by orthodontics alone Sturdevant’s Art and science of operative dentistry (fifth edition) 70
- 71. CONTRAINDICATIONS Available Enamel Ability ToEtch The Enamel Oral Habits : Bruxism and Biting On Foreign Object Sturdevant’s Art and science of operative dentistry (fifth edition) 71
- 72. ADVANTAGES 1. Minimally invasive 2. Aesthetically pleasing 3.Durable 4. The ability to elicit a good tissue response Sturdevant’s Art and science of operative dentistry (fifth edition) 72
- 73. DISADVANTAGES They are technique-sensitive andtime-consuming to place Repair can be difficult Their color cannot easily be modified once placed Prior to cementation they are fragile and difficult to manipulate Sturdevant’s Art and science of operative dentistry (fifth edition) 73
- 74. Direct gold filling ▪Granular ▪ Electrolytic precipitate ▪ Foil Forms of direct filling gold Gold is the oldest dental restorative material, having been used for dental repairs for more than 4000 years. A gold foil restoration is a filling technique of decayed teeth that exploits the properties of gold of being welded in its cold state, due to its highly cohesive nature. Sturdevant’s Art and science of operative dentistry (fifth edition) 74
- 75. CLINICAL CONSIDERATIONS ▪ Resilienceof dentine and the adaptability of gold allow an almost perfect seal between the tooth structure and gold. ▪ Gold is resistant to corrosion, shows no shrinkage or expansion, and therefore is an ideal dental filling material. ▪ The advantages of gold foils restorations are that they can last for a long time if correctly done Vimal K Sikri 4th edition , Sturdevant’s Art and science of operative dentistry (fifth edition) 75
- 76. ADVANTAGE: ▪ When properly placed,direct gold is the most durable restorative material available. ▪ It does not undergo tarnish and corrosion in the oral cavity. ▪ It exhibits good adaptation to the cavity walls. ▪ The density and hardness of compacted gold provide adequate compressive strength. Vimal K Sikri 4th edition, Sturdevant’s Art and science of operative dentistry (fifth edition) 76
- 77. DISADVANTAGES Technique sensitive, andto achieve excellence great skill, patience and time is required. ▪ The welding technique, with or without a mallet, can generate a pulpal trauma. ▪ Do not have high mechanical resistance against masticatory forces, they are only suitable for very small cavities. ▪ Because of the high thermal conductivity of gold, larger restoration can enhance sensitivity, and a larger restoration is very complex to finish and polish. ▪ Gold foil is more expensive than any other restoration material Sturdevant’s Art and science of operative dentistry (fifth edition) 77
- 78. INDICATIONS ▪ Generally, gold foilrestorations are used for incipient or early lesions, generating small cavities in non stress-bearing areas, and where aesthetic concern is limited. ▪ The American Academy of Gold Foil Operators indicates class 1, class 2, class 3, class 5, and class 6 cavities. The dimensions illustrated in their guidelines are small. ▪ Repair of casting margins. ▪ Technical skill of dentist is important Craigs 13th edition ,Marzouk 1st edition, Vimal K Sikri 4th edition ,International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 78
- 79. CONTRAINDICATIONS Teeth with verylarge pulp chambers because of their greater susceptibility to get damaged during condensation. ▪ Severely periodontally weakened teeth -unable to withstand the condensation forces. ▪ They are not generally used in children, elderly and handicapped patients who cannot give very long sittings. ▪ Root canal filled teeth are generally not restored with DFG as these teeth are brittle. ▪ Large carious lesions as DFGs cannot withstand heavy masticatory forces and also a greater expenditure would be required. ▪ Poor accessibility and isolation. Sturdevant’s Art and science of operative dentistry (fifth edition) 79
- 80. CAST GOLD RESTORATIONS Advantage: •▪ Strength • ▪ Accurate reproduction of contacts and contours. • ▪ Noble and inert • ▪ Abrasion resistance • ▪ Reduced internal stresses • ▪ Extra oral finishing and polishing Sturdevant’s Art and science of operative dentistry (fifth edition) 80
- 81. Disadvantage: • ▪ Microleakage •▪ More number of appointment • ▪ Need for temporary restoration • ▪ Cost • ▪ Technique sensitive • ▪ Esthetics Vimal K Sikri 4th edition 81
- 82. Indications • ▪ Whenthe cavity width does not exceed 1/3rd the intercuspal distance. • ▪ In case of extensive proximal caries involving the buccal and lingual line angles of the tooth. • ▪ In grossly carious tooth where one or more but not all cusps need coverage. Vimal K Sikri 4th edition 82
- 83. Contraindication ▪ Not usedas a abutment for a fixed or removable prosthesis. ▪ High caries rate As post endodontic restorations as they can wedge and fracture the remaining tooth structure. ▪ When cost is a major factors. Not preferred in case of grossly destroyed teeth with weak cusps Vimal K Sikri 4th edition 83
- 84.
- 85. In summary, threeinterrelated factors are important in the long-term function of dental restorative materials: (1) material choice, (2) component geometry (3) component design Selection of the suitable restorative material may determine the success of the final restoration. Intelligent selection of restorative material depends upon thorough evaluation of the currently available restorative materials in the light of all the conditioning factors presented by each individual case. Craigs 13th edition ,Marzouk 1st edition, Vimal K Sikri 4th edition ,International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 85
- 86. Some of theconditioning factors may modify the selection of restorative materials but should never justify using material of inferior qualities unless decided by the patient after being discussed with him. In the absence of the ideal restorative material combination of two or more materials may be used to obtained the required qualities. Craigs 13th edition ,Marzouk 1st edition, Vimal K Sikri 4th edition ,International Journal of Current Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 86
- 87. International Journal ofCurrent Research Vol. 9, Issue, 01, pp.45719-45722, January, 2017 SELECTION OF RESTORATIVE MATERIALS IN CONSERVATIVE DENTISTRY Sturdevants operative dentistry 5th edition Roberson TM, Heymann H., Swift EJ. Sturdevant’s Art and Science of Operative Dentistry: 5th edition; 2006 by Mosby Inc Sikri VK. Textbook of Operative Dentistry: 2nd edition; 2008 by CBS Kenneth J. Anusavice. Phillips’ Science of Dental Materials: 11th edition; 2003 by Elsevier Craigs 11th edition 87
- 88.
- 89. PROPERTY OF AMATERIAL IS IMPORTANT TO REATAIN MATERIAL IN NCCL’S? • ELASTIC MODULUS property of a material is important to retain a material in NCCL’s • The term elastic modulus describes the relative stiffness or rigidity of a material within elastic range • This property is independent of heat/ mechanical treatment, but is quite dependent on COMPOSITION of material 89
- 90.
- 91. COMPOSITE FOR CLASSV RESTORATIONS AND WHY? • Microfilled composite; because of extended working time & control of contour before polymerization • It tends to flex with tooth when used in abfracture lesions • Surface lusture similar to enamel 91
- 92. RMGIC • The diametraltensile strength of RMGIC is higher than that of the conventional. • show a very small initial shrinkage of the resin component at the time of light activation • They exhibit a greater degree of shrinkage on setting due to polymerization • Lower wear resistance as compared to composite PMCR • Superior working characteristics to RMGIC • Restorations of class III cavities • Restoration of Class V lesions • Restorations of erosion lesion 92
- 93.