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  2. 2.  Glass Ionomer is the Generic name of a group of materials that use silicate glass powder and an aqueous solution of polyacrylic acid. Alumino silicate powder
  3. 3.  They are a hybrid of dental silicate and zinc poly carboxylate and are called as polyalkenoate cements, ASPA. Glass ionomer is a combination of „Glass‟powder and „ionomer‟-ic acid GIC can be defined as a water- based material that hardens following an acid-base reaction between the basic fluoro aluminosilicate glass powder and an acidic solution of polyacrylic acid.
  4. 4. CLASSIFICATION Type I – Luting Type II- Restorative Type III- Liner and base
  5. 5. CLASSIFICATION1. Glass ionomer cements a. (i) Glass polyalkeonates (ii) Glass polyphonates b. Resin modified GIC c. Polyacid modified composite resin2. a. Auto-cure b. Dual cure c. Tri cure
  6. 6. CLASSIFICATION3. a. Type I – Luting b. Type II - Restorative Type II. 1. Restorative aesthetic Type II. 2. Restorative reinforced c. Type III- Lining or Base
  7. 7. CLASSIFICATION1.Traditional or conventional2. Metal modified GIC a. Cermets b. Miracle mix3. Light cured GIC4. Hybrid (Resin modified GIC)5. Polyacid modified resin composite orCompomer
  8. 8. CLASSIFICATION :1. Type I - Luting2. Type II - Restorative3. Type III - Fast setting lining4. Type IV - Fissure sealants5. Type V - Orthodontic cements6. Type VI - Core build up material7. Type VII - High fluoride releasingcommand set GIC8. Type VIII - GIC for AtraumaticRestorativeTreatment (ART)9. Type IX - Geriatric and Paediatric GIC
  9. 9. COMPOSITION :The composition of the glass is an acid solubleFormed by fusing silica[Sio2], alumina [Al2O3],calcium fluoride / fluorite(CaF2), metal oxides andmetal phosphates at 11000C to 15000C temperature.The glass is crushed, milled and then ground to afine powder {20u – 50u)
  10. 10. COMPOSITION OF CALCIUM FLUROALUMINOSILICATE GLASS POWDER COMPONENT WEIGHT% SiO2 [quartz] 29 Al2O3 [alumina] 16.6 CaF2[fluorite] 34.2 Na3AlF6[cryolite] 5 AlF3 5.3 AlPO4 9.9
  11. 11. COMPOSITION•The liquid was an aqueous solution of in a concentration of about 50%.•The liquid was quite viscous and tended to gel overtime.•Hence, acrylic acid was copolymerised with otheracids such as iticonic ,maleic,and tricarboxylic acid.
  12. 12. COMPOSITIONThe use of copolymer :- Decrease the viscosity of the liquid- Reduces the tendency for gelation and thusimproving storage- Increases the reactivity of the liquid
  13. 13. COMPOSITION•It is one of the most important constituents of glassionomer cement.•It is the reaction medium•30%
  14. 14. COMPOSITION The polyacrylic acid can be vacuum driedand incorporated with the glass powder. The liquid then used can be either water or adilute aqueous solution of tartaric acid.
  15. 15. SETTING REACTION The setting reaction of glass Ionomer cements involves three overlapping stages.Stage1: DissolutionStage2: Precipitation of salt, gelation and hardeningStage3: Hydration of salts.
  16. 16. SETTING REACTION At the beginning of reaction the surface of glass particles is attacked by the polyacid. The hydrogen ions that are released from the acid diffuse to the glass, and make up for the loss of the calcium aluminium and fluoride ions.
  17. 17. SETTING REACTION During this stage calcium and aluminum ions bind to polyanions via the carboxylate groups. The initial set is achieved by cross-linking of the more readily available calcium ions. This is the gelation phase and this reaction is relatively rapid, usually forming a clinically “hard” surface within 4-10 minutes from the start of mixing.
  18. 18. SETTING REACTION Maturation occurs over the next 24 hours as the less mobile aluminium ions become bound within the cement matrix, leading to more rigid cross linkng between the polyacid chains. Fluoride and phosphate ions form insoluble salts and complexes. Sodium ions contribute to the formation of an orthosilicic acid on the surface of the particles
  19. 19. SETTING REACTION Associated with the maturation phase is a progressive hydration of the matrix salts, leading to sharp improvement in the physical properties
  20. 20. SETTING REACTIONThe glass ionomer cements are water-based cements.It‟s functions include: It is reaction medium.It serves to hydrate the siliceous hydrogel and themetal salts formed. It is essential part of the cement structure.If water is lost from the cement by desiccation while itis setting, the cement-forming reactions will stop.
  21. 21. Water present in the set cement can be arbitarilyclassified into: “ ” which is readily removed bydesiccation.This water is loosely bound to the calcium ions “ ” which cannot be removed. Tightly bound water is associated with thehydration shell of the aluminium cation-polyacrylate bond and some silica gel water.
  22. 22. ADHESION OF GICGlass ionomer cements have the important propertyof adhering to untreated enamel and dentin. Itreacts with the smear layer on cut dentin and alsobonds to other reactive polar substrates such as thebase metals.Adhesion – 225MN/m2 after 7 days
  23. 23. ADHESION OF GICPolyalkenoic acid attacks the dentine and enamel anddisplaces phosphate and calcium (or strontium) ions.These migrate into the cement and develop an ion enrichedlayer firmly attached to the tooth structure.Dentinal tubules will remain sealed and microleakage canonly occur into the cement.
  24. 24. Mechanical Properties Compressive Strength :150-200 Mpa. compressive strength is increased by increasing alumina content but this is achieved at the expense of translucency. The finer the particles the more will be the compressive strength Tensile Strength :Glass ionomers has a higher tensile strength when compared with silicates tensile strength 6.5 Mpa –17.4 Mpa. Flexure strength :Glass Ionomer cements are relatively brittle having a flexure strength of only 15-20 Mpa and can not be considered suitable purpose filling material for permanent teeth.
  25. 25. Mechanical Properties Hardness :It is less than that of silicates the value is 48 KHN Fracture Toughness :Glass Ionomer cements are much inferior to composites in this aspect.
  26. 26. PHYSICAL PROPERTIESBIOCOMPATIBILITY: The glass ionomer cements are therapeutic materials. Their adhesion to tooth material ensures that they provide an excellent and enduring marginal seal, thus eliminating secondary caries while sustained release of fluoride confers resistance to caries on adjacent tooth material (i.e. there is a reduction in „contact‟ caries). These cements are not only biocompatible they are bio-active, because when they are used as bone cements they promote bone- healing
  27. 27.  Fluoride ions released from the restorative materials become incorporated in hydroxyapatite crystals of adjacent tooth structure to from structure such as fluorapatite that is more resistant to acid mediated decalcification. The fluoride originates from that used in preparing the alumino silicate glass, which can contain upto 23% fluoride
  28. 28. DURATION OF FLUORIDE RELEASE Large amounts of fluorides are released during the first few days after placement after which it gradually declines during the first week and stabilizes after 2-3 months and continues for a long time that is 8 years after placement and certainly longer.
  29. 29.  The glass ionomer cement is an aestheticfilling material because it has a degree oftranslucency which arises because it‟s filler is aglass. The colour of glass ionomer remainsunaffected by oral fluids as compared tocomposites which tend to stain.
  30. 30. A correctly manipulated and protected glassionomer material shows a volumetric settingcontraction of approximately 3% which developsslowly through the setting process.
  31. 31. Thermal Properties: The thermal diffusivity value of glass Ionomer cement ions is close to that for dentin. Hence the material has an adequate thermal insulating effect on the pulp and helps to protect it from thermal trauma
  32. 32. 1. RESTORATIVE MATERIALS:• Restoring of erosion/ abrasion lesions withoutcavity preparation.• Sealing and filling of occlusal pits and fissures• Restoration of deciduous teeth.• Restoration of class III lesions, preferably using alingual approach with labial plate intact.
  33. 33. • Repair of defective margins in restorations• –proximal lesions –buccal and occlusal approach (tunnelpreparation)• Core build-up• Provisional restorations where future veneercrowns are contemplated• Sealing of root surfaces for over dentures.
  34. 34. 2. FAST SETTING LINING CEMENT AND BASES:• Lining of all types of cavities where a biologicseal and cariostatic action are required• Replacement of carious dentin or theattachment of composite resins using the acid etchtechnique• Sealing and filling of occlusal fissures showingearly signs of caries.3. LUTING CEMENT:
  35. 35. CONTRAINDICATIONS: Class IV carious lesions of fractured incisors. Lesions involving large areas of labialenamel where esthetics is of major importance Class II carious lesions where conventionalcavities are prepared; replacement of existingamalgam restorations. Lost cusp areas.
  37. 37. ISOLATION:Glass isonomer cements are sensitive to moisure contamination during placement, so we need to isolate the tooth surface using rubberdam,cottonrolls,retraction cords and saliva ejectors.TOOTH PREPARATION : It consists of A) Cavity preparation- this is required while restoring class III or class V carious lesions. For abration and erosion defects there is no need of cavity
  38. 38.  B) Prophylaxis- It is done usingpumiceslurry carried in a bristle brush. This will remove any plaque or salivary pellicle from tooth surface C) Surface conditioning- It is an important step in promoting good adhesion using 10% polyacrilic acid for 10 to 15 seconds. Other agents are 10% citric acid, 3% hydrogen peroxide, 10% EDTA, 25% tannic acid. Advantages are a) It lowers the surface energy of the tooth thus increasing wettability by glass ionomer cement b) It
  39. 39. MANIPULATION OF GIC a. Dispense both powder and liquid carefully. Turn the liquid bottle to the horizontal briefly to allow liquid to flow into the tip before turning it to the vertical and squeezing out a single drop. b. Divide the powder into two equal parts and prepare to mix. c. Incorporate the first half of the powder within 10 seconds, rolling the powder into the liquid without spreading the mix over the slab. Do not spatulate too much. d. Complete the mixing within 25-30 seconds. For preference, place into a disposable syringe for transfer to the cavity.
  40. 40. 1. the appropriate of the cement.2. the tooth with rubber dam where there is any risk of gingival Seepage or bleeding. ---Erosion/abrasion lesion:- clean only with pumice slurry ---Carious lesion: conventional instrumentation to remove caries and provide some mechanical retention.
  41. 41. 4. Where there is less than 0.5mm of remaining dentin. Line the cavity with a setting5. Apply a to the cavity to remove the smear layer and improve adhesion. for 30seconds
  42. 42. Polyacrylic acid: 10% polyacrylic acid for 10 seconds. It removes surface debris and smoothes out irregularities. It tends to open up dentinal tubules. It is the conditioner of choice as it is a part ofthe cement forming system.
  43. 43. Citric acid:50% citric acid for 5 seconds was the earliestconditioner used : 25% for 30 seconds.
  44. 44. 7. Dispense the cement on a cooled glass slab and mix quickly (30 seconds for hand mixing and 10 seconds for machine mixing). Alternatively a paper pad can be used. The mix should have a glossy appearance.8. The surface should be as this tends to reduce the wettability.9. Insert the cement using a spatula or a syringe
  45. 45. 10. Place a preshaped wherever possible. Allow to set.11. Remove the matrix and
  46. 46. 13. Trim any excess, external to the cavity with scalpel blade.14. Reapply varnish or bonding agent.15. The final should be till the next appointment or at least16. or bonding agent after polishing.
  47. 47. Glass ionomers are available commerciallyin two forms:- supplied separately, orhand mixing.- or mechanical mixing.
  48. 48. HAND MIXING: Certain points to be noted while mixing anddispensing GIC are:• Low exotherm while mixing GIC enables allthe powder to be incorporated into theliquid The recommended P:L ratio should befollowed.(3:1)
  49. 49.  Mixing on a chilled slab can significantlyprolong working and setting time.  Plastic or agate spatula are usually used for mixing  A smooth glossy plastic paste should be produced by spreading the mix across the slab and then re-gathering it to reduce
  50. 50.  A dry mix will not adhere to the tooth due toinsufficient wetting. A glossy mix indicates thepresence of free surface polyacid for iondisplacement at the enamel dentin interface. Setting time – Type I – 4 to 5 minutes Type II- 7 minutes
  54. 54. Pits and fissures Primary Teeth restorations Bracket Bonding
  55. 55. Luting of crowns Core Build-up
  56. 56. GLASS IONOMER AS LINER AND BASE Glass-ionomer cement as a lining. A lining is used to protect the pulp from temperature change so the lining needs to be only 0.5mm thick overall. Glass-ionomer cement as a base.
  57. 57. LAMINATION OR SANDWITCH TECHNIQUE This technique involves a combination of glass Ionomer cement and composite or amalgam. The rationale behind the technique is to make the most of the physical and aesthetic properties of each material. Ionic adhesion of glass Ionomer cement to the dentin with release of fluoride and thus making the area resistant to recurrent caries. Less composite resin to be placed, thus minimizing the ultimate shrinkage of the composite resin, which will occur during light activation. Minimize the number of increments of composite resin to be placed and light activated, thus saving time.
  58. 58. Main Steps in this Technique: Mixing and placement of cement. Acid etching Application of resin bonding agent. Placement of the overlying composite resin.
  59. 59. Lamination with Amalgam This combination is likely to be used in restoration of a molar teeth that is expected to withstand a relatively heavy occlusal load.
  60. 60. Glass Ionomer Resin-modified Silicate cement cermet (Type II) Glass IonomerCompressivestrength (24 hr) 180 150 150 105MPa 26,000 22,000 22,000 15,000PsiDiametral tensilestrength (24hr) 3.5 6.6 6.7 20MPa 500 960 970 2,900PsiHardness (KHN) 70 48 39 40Pulp response Severe Mild Mild MildAnticariogenic Yes Yes Yes YesSolubility ( test) 0.7 0.4 - -
  61. 61. RECENT ADVANCES IN GLASSIONOMER CEMENTS - Highly viscous gic / packable gic/condensable gic -Low viscosity gic
  62. 62. • Miracle mix - Cermet
  63. 63. • - Low ph “smart” materials - Fluoride charge materials
  64. 64. IMPROVED TRADITIONAL GLASS IONOMERSHIGHLY VISCOUS GLASS IONOMERDue to the possibility of reduced secondary cariesby fluoride release and to the comparative ease ofuse of conventional glass ionomers, furtherdevelopments have been made for posteriorrestorations in primary and permanent dentition.
  65. 65. This material was developed largely as aresponse to the need for filling materials in theatraumatic Restorative Therapy or “ART ”.
  66. 66. Ketac Molar (EPSE)---- Powder : Ca, Na, Alfluorosilicate glass. The mean particle size is 2.7µm for ART-Liquid: polycarbonic acid, tartaric acid and water.Benzoic acid is used as a preservative---- P:L : 2.9:1
  67. 67. Uses Geriatric and pediatric restorations Final restorations (non-stress areas) Intermediate restorative (irm) Core material Long term temporary restoration
  68. 68. Advantages of condensable GICover conventional GIC They are packable and condensable They are easy to place They are non-sticky Early moisture sensitivity is reduced
  69. 69.  Rapid finishing can be carried out Improved wear resistance. Low solubility in oral fluids.
  70. 70. DISADVANTAGES OF THESE GIC’S ARE: Due to their opacity, they have esthetic disadvantages They have limited life potential. Moderately polishable
  71. 71. LOW VISCOCITY GLASS IONOMERS• This type of glass ionomer has been developed asliners, fissureprotecting materials for hypersensitive cervicalareas and endodontic materials.•Such materials are designed with low powder-liquid ratios and highly flowable.
  72. 72. •These are used as fissure protection materials during theeruption period of the teeth.
  73. 73. METAL – MODIFIED GLASS IONOMERCEMENTS Glass ionomer cements lack toughness and hence, cannot withstand high-stress concentrations. GIC have been modified by the inclusion of metal filler particles in an attempt to improve toughness Two methods of modifications have been
  74. 74. SILVER ALLOY ADMIX or MIRACLE MIX• Sced and wilson (1980) found that amalgam alloyscould be incorporated into glass ionomer cementsand that these served to increase the flexurestrength.• Spherical silver amalgam alloy powder is mixedwith Type II glass ionomer powder in the ratio 7:1.
  75. 75. • These systems have been used clinically bySimmons(1983).• However, their esthetics are poor –they tend toimpart a gray to blackish colour to the cement –and they do not take burnish.
  76. 76. CERMET – IONOMER CEMENTS: In an attempt to improve the abrasion resistance and strength of GIC, developed the “cermet”-ionomer. These cements, unlike simple mixtures of alloy particles or metal fibres, contain glass-metal powders sintered to high density that can be made to react with polyacids to form a cement.
  77. 77. Strength:The compressive as well as the tensile strength ofthe cermet cement is higher than that of thetraditional glass ionomer cement.Modulus of elasticity:tends to be relatively lower than the conventionalglass ionomers
  78. 78. Abrasion resistance:The silver cermets materials, where the silverparticles are incorporated in the glass, have moreresistance to abrasion.Radio opacity:The silver cermet radiopacity approaches that ofdental
  79. 79. Fluoride release: Fluoride leaches out from both metal-modified systems in appreciable amounts. Less fluoride is released from the cermet than from its Type II counterpart.
  80. 80. INDICATIONS: As an alternative to amalgam in conservativeClass I cavities in primary teeth. Core build –up material Lining of class II amalgam restorations. Root caps for teeth under overdentures Preventive restorations and temporaryposterior restorations.
  81. 81.  Anterior restorations. Areas subjected to high occlusal loading.
  82. 82. “Resin –modified glass ionomer materialsthat are modified by the inclusion of resin,generally to make them more photocurable”
  83. 83. The powder component of a typical light- curedmaterial consists of ion leachable glass andinitiators for light or chemical curing or both
  84. 84.  The liquid component usually contains water, polyacrylic acid with or without some carboxylic acid modified with methacrylate and Hydroxyethyl methacrylate monomers.Powder : liquid ratio = 3:1.
  85. 85. 1. Translucency and color: Excellence translucency is seen immediately after light activation.2. Solubility and disintegration: They appear to be more resistant to solubility and disintegration than the auto cure GICs3. Fluoride release: The light cured GIC liner, in fact, releases more fluoride
  86. 86. 4. Strength: The diametral tensile strength of RMGIC is higher than that of the conventional.5. Dimensional change: The RMGIC show a very small initial shrinkage of the resin component at the time of light activation.6. Marginal Adaptation: They exhibit a greater degree of shrinkage on setting due to polymerization
  87. 87. Adhesion to tooth structure: Bonding mechanism issimilar to conventional GICAdhesion to other restorative material:RMGIC areprimarily used as liners and bases although theyalso can be used for restorations.Antibacterial effect: According to articles(DCNA1998), RMGIC is said to have greater antibacterialeffect than calcium hydroxide.
  88. 88.  Can be finished and polished immediatelyafter set Repairs can be carried out, as bond betweenold and new material is very strong. Exhibits increased adhesion to compositewhen used a base
  89. 89.  Ideal under composite as it can be etchedimmediately Fluoride release is greater than conventionalGIC and compomers High diametral strength of 20MPa
  90. 90. - Biocompatibility is controversial- Setting shrinkage is higher (-1%) and hence, microleakage is more and marginaladaptation is poor- Lower wear resistance as compared tocomposite.
  91. 91. USES: • Used as a liner and base • Pit and fissure sealant • Core build-up material
  92. 92. A new variety of the usual composite resinscomprising resins and inorganic filler particles isthe polyacid-modified composite resin or“compomer” which was introduced in the early1990s.
  93. 93. Commercial Products Compoglass F Principle Compoglass Flow
  94. 94.  Compomer can be defined as a resin compositewith fluoride releasing potential. Polyacid – modified glass ionomer cement isdefined as materials that may contain either orboth of the essential components of glass ionomercements but at levels insufficient to promote theacid- base curing reaction in the dark.
  95. 95. The compomers presently available contain resinsand fillers common to composite resins and glassionomers. They include reactive ion-glass particleand polymerizable acidic monomers. They areusually one Component material.
  96. 96.  Sealing and filling of occlusal pits andfissures Restorations of primary teeth Minimal cavity preparations Lining Core build-up
  97. 97.  Repair of defective margins in restorations Restorations of class III cavities Restoration of Class V lesions Restorations of erosion lesion Sealing of root surface for over dentures Potential root canal sealers Retrograde filing materials in endodonticsurgeries
  98. 98. CONTRA INDICATIONS Class IV carious lesions Lesions involving large areas of labial surface Class II carious lesions where conventionalcavities are prepared Lost cusp areas Under full metal or PFM crowns where lightcannot penetrate
  99. 99. ADVANTAGES Superior working characteristics toRMGIC Ease of use Easily adapts to the tooth Good esthetics
  101. 101. ANTICARIOGENIC Yes Yes YesSOLUBILITY 0.4FLUORIDERELEASE (ug F) 14 days 440 200 1200 30 days 650 300 1600BOND STRENGTH 1.1-4.5(to <TYPE II 13.4MPa dentin)
  102. 102. DIRECT COMPARISON OF CONVENTIONAL GIC, RMGIC AND COMPOMER CHARACTERISTIC CONVENTIONAL GIC RESIN MODIFIED POLYACID GIC MODIFIED GIC Handling properties/ Powder-liquid Powder – liquid One component preparation of the systems, aqueous Systems, Water- material, no water material based; hand-mixed monomer based; and no versions or hand-mixed or mixing precapsulated Precapsulated systems systems Working time 1-2 minutes Several Unlimited (light minutes (setting Cured) initiated by light curing) Setting mechanism Acid – base Light curing (40 Light curing only (40 reaction (4-8 minutes), seconds); radical seconds); second phase within the Polymerisation and Incremental next 24 hours acid –base reaction technique
  103. 103. Moisture sensitivity High, especially Moderate to low Noneafter placement during first setting Stage. protective covering requiredFinal finish Fair Good ExcellentAdhesion to tooth Self adhesive; Self adhesive;Structure chemical bond to Primer needed for enamel and dentin Certain products
  104. 104. Strength High compressive High compressive strength; low Strength; medium flexural strength flexural strengthWear resistance Low ; highly Poor Viscous cements- Moderate to acceptable
  105. 105. Thank u