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  1. 1. Glass ionomer cement & its recent advances Jagadeesh k 1st yr p.g Dept. of conservative dentistry & endodontcs G.D.C.H,VIJAYAWADA
  3. 3. INTRODUCTION DEFINITION of cement A cement is a substance that hardens to act as a base , liner , filling material or adhesive to bind devices or prosthesis to the tooth structure or to each other. - philips’ science of dental materials (12th ed) • Glass ionomer cement is a water based cement • ADA specification number: 96
  4. 4. Definition Glass-ionomer is the generic name of a group of materials that use silicate glass powder and aqueous solution of polyacrylic acid” -Kenneth J Anusavice.
  5. 5. History •1965 –A.D Wilson mixed dental silicate glass powder & aqueous solutions of various organic acids including poly acrylic acid Set cement is sluggish Not reported or published. • The invention of glass ionomer cement was done in 1969.first reported by Wilson and Kent in 1971.( ASPA I) • First practical material: ASPA II in1972 by Crisp and Wilson,added tartaric acid. • ASPA III- Methyl alcohol was added. • First marketable material, ASPA IV in 1973 • Luting agent ASPA IVa in 1975 by Crisp and Abel
  6. 6. •Metal reinforced cements in 1977 by Sced and Wilson • Cermet ionomer cements in 1978 by Mc Lean and Glasser • Improved traslucency, ASPA X by Crisp, Abel,Wilson in 1979 • Water activated cements, ASPA V in 1982 by Prosser et al. • CLINICAL DEVELOPMENT • First clinical trials in 1970 by Mc Lean • Class I restorations, fissure sealing and preventive dentistry in 1974 by Mc Lean and Wilson • Erosion lesions, deciduous teeth, lining, composite ionomer laminates in 1977 by J. W. Mclean & A. D. Wilson. • Improved clinical techniques between 1976-77 by G.J.Mount & Makinson,1978
  7. 7. • Approximal lesions and minimal cavity preparation in 1980 by Mc Lean • Water activated luting cements in 1984 by Mc Lean et al • Tunnel class I and II preparations by Hunt and Knight in 1984 • Double etch ionomer /composite resin laminates,1985, Mc Lean
  8. 8. Other names • Glass ionomer-term coined by wilson & kent glass-alumino silicate glass particles ionomer-poly carboxylic acid. • ISO terminology- poly alkenoate cement. • Since its extensive usage to replace the dentin ,has given different names Dentin substitute Man made dentin Artificial dentin •Introduced into u.s as ASPA-Alumno silicate polyacrylate
  9. 9. Composition • The glass ionomer powder is an acid soluble calcium fluoroalumino silicate glass- ion leachable glass. • Composition of two commercial glass ionomers Compound Composition A(wt%) Composition B(wt%) SiO2 41.9 35.2 Al2O3 28.6 20.1 AlF3 1.6 2.4 CaF2 15.6 20.1 NaF 9.3 3.6 AlPO4 3.8 12.8
  10. 10. • The raw materials are fused to a uniform glass by heating them to a temp.of 1100 °C- 1500°C. • Lanthanum,strontium,barium or zinc oxide additions provide radio opacity. • The glass is ground into a powder having particles in the range of 15-50 µm. •ROLE OF COMPONENTS IN POWDER •The role of Al2O3 & SiO2 of the glass is crucial and is required to be of 1:2 or more by mass for cement formation. •CaF2-Supplemented by the addition of cryolite (Na3AIF6). •This flux -reduces the temperature at which the glass will fuse -increases the translucency of the set cement.
  11. 11. • Fluoride is an essential constituent which - Lowers fusion temp., acts as flux - improves working characteristics & strength - improves translucency - improves therapeutic value of the cement by releasing fluoride over a prolonged period • Al3PO4-Improves translucency. Apparently adds body to the cement paste
  12. 12. •LIQUID •Polyacrylic acid --- 45 % •Water --- 50 % •Modifiers Itaconic acid --- 05 % maleic acid tricarballylic acid viscosity ,inhibits gelation , shelf life. •Tartaric acid --- Working Time & setting time.
  13. 13. • The liquid is an aqueous solution of polymers andcopolymers of acrylic acid. • In most of the current cements,the acid in the form of a coploymer with itaconic ,maleic ,or tricarboxylic acids. • polyacrylic acid-is the most important acid contributing to formation of the cement matrix. • Water- • It is reaction medium. • It serves to hydrate the siliceous hydrogel and the metal salts formed. • It is essential part of the cement structure. If water is lost from the cement by desiccation while it is setting, the cement-forming reactions will stop.
  14. 14. •Glass ionomer cements are water-based materials •Plays a role in transporting calcium and aluminium ions to react with poly acids. •Types: - Lossely bound water -Tightly bound water •With the aging of cement, the ratio of tightly bound to loosely bound water increases •Accompanied by an increase in strength, modulus of elasticity and decrease in plasticity •Cement is only stable in an atmosphere of 80% relative humidity
  15. 15. • In higher humidities the cement absorbs water and the consequent hygroscopic expansion can exceed the setting shrinkage. • Cement can lose water under drying conditions, however leading to shrinking and crazing. • Susceptibility to desiccation decreases as the cement ages • This is prevented if protected for about 10 to 30 mins (depends on manufacturer). • ITACONIC ACID • Itaconic acid promotes reactivity between the glass and the liquid. • It also prevents gelation of the liquid which can result from hydrogen bonding between two polyacrylic acid chains
  16. 16. • A stronger acid than polyacrylic acid • Causes the cement to harden and lose its moisture sensitivity faster. • More carboxyl (COOH) groups which lead to more rapid polycarboxylate crosslinking Maleic acid
  17. 17. • Tartaric acid • The 5% optically active dextro-isomer of tataric acid is incorporated. • It is also hardener that controls the PH of the set cement during setting process, which in turn controls the rate of dissolution of the glass. • It facilitates extraction of ions from the glass. • It typically increases the working time and also aids in snap test.
  18. 18. CLASSIFICATION A.ACCORDING TO A.D. WILSON AND J.W.McLEAN IN 1988 Type I --- luting cements Type II --- restorative cements a.Restorative aesthetic b.Restorative reinforced B. ACCORDING TO SKINNERS Type I – Luting Type II- Restorative Type III- Liner and base
  19. 19. C. ACC.TO CHARACTERISTICS SPECIFIED BY MANUFACTURER • Type I --- Luting cement eg. Fuji I, KETAC • Type II --- Restorative material eg. Ketacfil, Fuji II, fuji IX • Type III --- a. Bases & liners -- weak with less acidic b. Bases & liners -- stronger but more acidic c. Bases & liners -- strong even in thin layer • Type IV --- Admixture --- eg. Ketac silver, miracle mix D. ACCORDING TO J.W.McLEAN et al IN 1994 - Glass ionomer cement (traditional) -Resin modified glass ionomer cement -Poly acid modified composite resins
  20. 20. E. ACCORDING TO INTENDED APPLICATIONS • Type I – Luting • Type II – Restorative • Type III – Liner/base • Type IV – Pit & fissure sealant • Type V – Luting for orthodontic purpose • Type VI – Core buildup material • Type VII – High fluoride releasing command set • Type VIII – Atraumatic restorative treatment • Type IX − Pediatric Glass Ionomer cements
  21. 21. F. NEWER CLASSIFICATION • Traditional glass ionomer a. Type I --- Luting cement b. Type II --- Restorative cements c. Type III --- Liners&Bases • Metal modified Glass Ionomer a. Miracle mix b. Cermet cement • Light cure Glass Ionomer HEMA added to liquid • Hybrid Glass Ionomer/resin modified Glass Ionomer a.Composite resin in which fillers substituted with glass ionomer particles b.Precured glasses blended into composites
  22. 22. Cement placement Conditioning the Tooth Surface • Dentin conditioning prior to placement of a GIC is done primarily to remove the smear layer. • GIC is better able to wet the dentin surface. • Promotes ion exchange. • Chemically cleans dentin. • Increases surface energy.
  23. 23. Agents used Surface treatment Time of application(sec) Citric acid, 50% aq 30 Citric acid, 2% aq/alc 30 Poly (acrylic acid), 25% aq 30 Tannic acid, 25% aq 60 Surface-active solution 60 Dodicin, 0.9% aq 60 Na2EDTA, 2% aq 30 Na2EDTA, 15% aq 30 Sodium flouride, 3% aq 30 Ferric chloride, 2% aq/alc 30
  24. 24. Mixing of the cement Full spoon, no excess Tip liquid bottle to side, then invert completely If water / tartaric acid, only 1 drop used.
  25. 25. Liquid should not stay on paper pad longer than 1minute (some of it may soak into it) Don’t mix beyond 30 seconds The objective is – only wet the particle – no dissolving it. First half folded into liquid in 10-15seconds Second half incorporated in 15 seconds Small mixing area
  26. 26. Loss of gloss/ slump test GIC --- 60 – 90 sec Resin-modified GIC --3 – 3.5 min
  27. 27. Working time & setting time • It sets rapidly in the mouth that is within 3-5 min and hardens to form a body having translucency that matches enamel • Setting time for type I –GIC – 5 -7 min • Setting time for type II–GIC --10 min • Film thickness should not exceed 20µm for luting agents
  28. 28. Mixing capsules • To activate capsule apply pressure 3-4 seconds before placing in machine • Ultrahigh speed machine : 4000 cycles/minute • (< 3000 cycles/minute – not desirable)
  29. 29. Finishing technique • Best surface –cement allowed to set under matrix •Carving the cement external to the cavity margins with sharp knives or scalers •Finest abrasive should be used to minimize tearing •Finishing with rotary instruments should be done at subsequent visit
  30. 30. Setting reaction •1. acid-base reaction •2. light activated polymerisation • ACID – BASE REACTION • GIC formed by the reaction of three materials Fluoro alumino silicate glass powder Poly acrylic acid Water • An acid – base reaction occurs between the glass powder and the ionic polymer. • Water is essential because that is the medium through which ion transfer takes place
  31. 31. • Chemistry of cement forming reaction from initial mixing occurs in various stages • The glass particles are attacked at the surface by poly acid which leads to withdrawal of the cations thus the glass network breaks down to silicic acid. • Principally Al3+, Ca2+, F-, are released and migrate into aqueous phase of cement and form complexes Decomposition of glass & migration of ions
  32. 32. • Initially calcium complexes predominate but later Aluminium complexes are more. • pH and viscosity increases • At critical pH and ionic conc. Precipitation of insoluble poly acrylates takes place. • Initial set occurs due to calcium polyacrylate but hardening of cement is due to slow formation of aluminium polyacrylate Gelation and vulnerability to water
  33. 33. • When cement is not fully hardened Al, Ca, F and polyacrylate ions may leach out leading to irretrievable loss of cement matrix • Calcium acrylate is more vulnerable to water. So the freshly set cements are to be protected. • This process continues for about 24 hrs • Undergoes slight expansion and increase in translucency • Cement becomes resistant to dessication and strength also increases for at least a year Hardening and slow maturation
  34. 34. •Increase in strength and rigidity are associated with slow increase in cross linking.
  35. 35. Mechanism of adhesion • Polyalkenoic acid attacks dentine and enamel: displaces PO4,Ca ions • Migrate into cement and develop an ion enriched layer firmly attached to tooth structure. • The bond strength to enamel is always higher than that to dentin because of the greater inorganic content & greater homogenity.
  36. 36. MECHANISM • Smith – chelation of calcium(1968) • Beech – interaction between apatite and poly acrylic acid polyacrylate ions Ionic bonds with calcium ions in enamel and dentin
  37. 37. • Acc. to Wilson(1974) • Initial adhesion is by hydrogen bonding from free carboxylic groups • Progressively these bonds are replaced by ionic bonds • Polymeric polar chains of acids bridge the interface between cement and substrate • Acc. to Wilson, Prosser and Powis(1983) • Polyacrylate displaces and replaces surface phosphate and calcium from hydroxyapatite • An intermediate layer of Ca and Al phosphates and polyacrylates is formed.
  38. 38. Properties of Glass Ionomer cement luting cement PROPERTY VALUES 1.Setting time(min) 7.0 2.Film thickness(µm) 24 3.24 hr compressive strength(Mpa) 86 4.24 hr diametrical tensile strength(Mpa) 6.2 5.Elastic modulus(Gpa) 7.3 6.Solubility in water(Wt%) 1.25 7.Pulp response Mild to moderate
  39. 39. Restorative cements PROPERTY GLASS IONOMER II CERMET HYBRID IONOMER 1.Compressive strength(Mpa) 150 150 105 2.Diametrcal tensile strength(Mpa) 6.6 6.7 20 3.Knoop hardness(KHN) 48 39 40 4.Solubility(ANSI/ ADA Test) 0.4 - - 5.Pulp response mild mild mild
  40. 40. •Biocompatibility • Resistance to plaque because presence of F • Pulp response to GIC is favorable • Freshly mixed --- acidic pH 0.9 – 1.6 -- mild inflammation resolve 10 -20 days * used to protect mech / traumatic exposure of healthy pulp • Glass ionomer cement showed greater inflammatory response than ZOE but less than Zn phosphate cement, other cements but it resolved in 30 days (Garcia et al, 1981)
  41. 41. • The influence of fluoride action is seen of at least 3 mm around the glass ionomer restoration • Released for a sustained period of 18 months (Wilson et al 1985) • Thickly mixed cements release more flouride than thinly mixed ones. • Fluoride release is restricted by sodium and to some extent by calcium content and not the total fluoride content of the glass. Fluoride release
  42. 42. Fluoride recharge • Glass ionomers may have synergistic effects when used with extrinsic fluorides • In the presence of an inverse fluoride concentration gradient, glass ionomers may absorb fluoride from the environment and release it again under specific conditions • topical APF (acidulated phosphate fluoride), with fluoride rinses and fluoridated dentifrices recharging takes place
  43. 43. • Thermal Properties: •The thermal diffusivity value of GIC is close to that for dentin. • The material has an adequate thermal insulating effect on the pulp and helps to protect it from thermal trauma • Solubility & disintegration lower than ----Zn phosphate Zn polycarboxylate In water --- less than Silicate cement Resin-modified GIC is less resistant to solubility
  44. 44. • Compressive strength < silicate cement • Tensile strength --- higher -- silicates • Hardness < silicates • Wear resistance < composites • ESTHETICS • Glass ionomer cement has got a degree of translucency because of its glass filler • Unlike composite resins, glass ionomer cement will not be affected by oral fluids
  45. 45. • The esthetic quotient depends upon 1.Refractive index of glass particles and matrix 2.Particle size 3.translucency of glass particles • Specification limits of GIC 0.35 -.90 (for optimum aesthetics it is between 0.35 – 0.90 )
  46. 46. Durability Affected by the factors • Inadequate preparation of the cement • Inadequate protection of restoration • Variable conditions of mouth Failure rate is more a measure of clinician’s skill than inherent quality of the material • One of the longest observation periods for the conventional glass ionomers in non-carious cervical lesions showed retention in the order of 90% after 10 yrs for KetacFil
  47. 47. • Some other properties • Low exothermic reaction • Adheres chemically to the tooth structure • Less shrinkage than polymerizing resins • Dimensional stability at high humidity • F release discourages microbial infiltration • Early moisture sensitive --- requires protection • Poor abrasion resistance • Average esthetic
  48. 48. Indications • 1. Restorative materials: • Restoring of erosion/ abrasion lesions without cavity preparation. • Sealing and filling of occlusal pits and fissures • Restoration of deciduous teeth. • Restoration of class III lesions, preferably using a lingual approach with labial plate intact. • Repair of defective margins in restorations • Minimal cavity preparations – Approximal lesions, Buccal and Occlusal approach (tunnel preparation) • Core build-up
  49. 49. 2. Fast setting lining cement and bases: • Lining of all types of cavities where a biological seal and cariostatic action are required • replacement of carious dentin the attachment of composite resins using the acid etch technique • Sealing and filling of occlusal fissures showing early signs of caries. 3. Luting cement: • Fine grain versions of the glass ionomer Cements are used. • Useful in patients with high caries index
  50. 50. Pit & Fissure sealant • A cariostatic action is essential for caries preventive material GIC is recommended as a P and F sealant where the orifices of the fissure are patent . • The size of the fissure should allow sharp explorer tip to enter the crevice which should be > 100 µ wide. Otherwise, GIC can get lost through erosion due to its low wear resistance and solubility
  51. 51. Core buildup • The metal reinforced glass ionomer cements are used for this purpose • Glass ionomer cements reinforce the teeth &prevent root fracture when root canals are over widened.
  52. 52. Sandwich technique • Devolped by Mclean, • To combine the beneficial properties of GIC & composite. Clinical steps:- •After cavity preparation, condition the cavity to develop good adhesion with GIC. •Place Type III GIC into prepared cavity. •After setting, etch the enamel & GIC with orthophosphoric acid for 15 seconds. •This will improve micromechanical bond to composite resin. •Apply a thin layer of low viscosity dentin bonding agent & finally place the composite resin over GIC & light cure it.
  53. 53. Advantages • Polymerisation shrinkage is less,due to reduced bulk of composite. • Favorable pulpal response. • Chemical bond to the tooth. • Anticariogenic property. • Better strength,finishing,esthetics of overlying composite resin. • Microleakage is reduced • Minimization of no. of composite increments, therefore time is saved
  54. 54. GIC IN ENDODONTICS They are used for: • Sealing root canals orthogradely , retrogradely • Restoring pulp chamber • Perforation repair • Sometimes for repairing vertical fracture GIC was used because of : • Its capacity to bond which enhances seal & reinforce the tooth • Its good bio compatibility, which would minimize irritation to peri radicular tissues • Its F release, which imports an anti microbial effect to combat root canal infection
  55. 55. Contra indications • Class IV carious lesions or fractured incisors. • Lesions involving large areas of labial enamel where esthetics is of major importance • class II carious lesions where conventional cavities are prepared. • replacement of existing amalgam restorations. • Lost cusp areas.
  56. 56. Modifications of GIC Water settable glass ionomer cement :- • Liquid is delivered in a freeze dried form ,which is incorporated into the powder. • Liquid used is clean water.
  57. 57. METAL MODIFIED GIC MIRACLE MIX / SILVER ALLOY ADMIX GIC • Sced and Wilson in 1980 incorporated spherical silver amalgam alloy into Type II GIC powder in a ratio of 7:1 Powder • Glass –17.5% • Silver –82.5% Particle size of silver is 3 – 4µm Liquid • Aqueous solution of copolymer of acrylic acid and or maleic acid—37% • Tartaric acid 9%
  58. 58. Disadvantages • Poor resistance to abrasion • Resistant to burnishing • Poor aesthetics
  59. 59. GLASS CERMET • Also called as cermet ionomer cements • McLean and Gasser in 1985 first developed • Fusing the glass powder to silver particles through sintering that can be made to react with polyacid to form the cement • Sintering is done at high pressure more than 300MPa and at a temperature of 8000C which is ground to fine powder particle size of 3.5 µm • 5%titanium dioxide is added to improve aesthetics • It has excellent handling characteristics
  60. 60. Indications • Core build –up material • Root caps of teeth under over dentures • class I cavities in primary teeth • Lining for class SAF • Preventive restoration • Temporary posterior restoration Contraindications • Anterior restorations. • Areas subjected to high occlusal loading
  61. 61. PROPERTIES Strength- • Both tensile and compressive strength is greater than conventional glass ionomer cement Modulus of elasticity- • tends to be relatively lower than conventional GIC Abrasion resistance- • greater than conventional GIC due to silver particle incorporartion
  62. 62. Radiopacity: silver cermet radio opacity is equal to that of dental amalgam Fluoride release Type II cermet miracle mix • 2 weeks 440 ug 200 ug 3350ug • 1 months 650 ug 300 ug 4040 ug
  64. 64. RESIN MODIFIED GLASS IONOMER CEMENTS • developed by Antonucci, Mc Kinney and SB Mitra. • Addition of polymerizable resins to the formulation to import additional curing process to the original acid base reactions. Definition: RMGIC can be defined as a hybrid cement that sets via an acid base reaction and partly via a photo- chemical polymerization reaction. Eg:Fuji II LC, Vitrebond, Photac –Fil, Vitremer, FujiV.
  65. 65. Composition • Powder: Ion leachable glass and initiators for light / chemical / both types of curing • Liquid : water + Polyacrylic acid modified with MA and HEMA monomers. • The HEMA content is around 15-25% and water content is low to accommodate the polymerizable ingredients. • It is a powder : liquid system with P:L = 3:1
  66. 66. Setting reaction 2 distinct setting reactions occur • Acid base neutralization • Free radicle MA cure. This can occur purely via light cure or by a combination of LC and chemical cure. • Thus a cement can be termed - dual cure if cross linking is via acid base + LC or - tri cure if its via acid base + Light cure + chemical cure
  67. 67. polyalkenoic acids + calcium fluoroalumino silicate glass + methacrylate copolymer Siliceous hydrogel Glass core Toothstructure Ca2+ Al3+ F - F - F - F - F - Ca2+ Ca2+ Ca2+ Al3+ Al3+ Al3+Al3+ CO-O- CO-O- CO-O- CO-O- CO-O- CO-O- CO-O- CO-O- -O-CO CO-O- -O-CO CO-O- CO-O- Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ PO4 3- PO4 3- PO4 3- PO4 3- CO-O- Siliceous hydrogel Ca/Al polyacrylate matrix methacrylate copolymer (resin-modified GI) Conventional GIs (Acid-based reaction) Ca2+ = initial set (minutes) Al3+ = final set (days, weeks, months) Resin-modified GIs Light initiated or autocure (set w/o light)
  68. 68. properties • Esthetics: According to the Phillips’ science of dental materials 12th ed, there is a definite improvement in translucency as the monomer brings the refractive index of the liquid close to that of the glass particle. • Fluoride release: is same as that of the conventional but the lining version shows higher F release • Strength: The diametrical tensile strength is much higher but compressive strength and hardness is lesser.
  69. 69. • Adhesion: to tooth is reduced. This is expected because of reduction in carboxylic acid in the liquid and interruption of chemical bonding due to the resin matrix. -Adhesion to composites is increased due to the presence of residual non-polymerized functional groups within the RMGIC • Micro leakage: A higher degree of Microleakage is seen due to polymerization shrinkage • also due to reduced water and carboxylic acid content and reduces its wetting capacity
  70. 70. • Water sensitivity is considerably reduced. • The biocompatibility is controversial and precautions such as placing Ca (OH)2 in deep preparations should be taken. The transient temp. rise during setting is also a concern
  71. 71. INDICATIONS • Luting cement esp. in orthodontics • Liner and base • Pit and fissure sealant • Core build up material • For amalgam repair ADVANTAGES • Long Working time and Snap setting • Early water sensitivity is reduced • Rapid development of early strength
  72. 72. • No etching is needed either to tooth for adhesion or for the material if composite lamination is to be done. • Bonding to composite is higher • Finishing can be done immediately • F release • Diametrical tensile strength is higher • DRAWBACKS • Of course some drawbacks still need to be tackled such as increased shrinkage with concurrent microleakage Low wear resistance as compared to composites Its controversial biocompatibility
  73. 73. Two-bottle powder liquid system. Photac Fil Quick Aplicap GC Fuji Plus Capsule Ketac Nano; a paste-paste system using static mixing.
  74. 74. Recent advances in Glass ionomer cement
  75. 75. Polyacid modified GIC / Compomer Self hardening GIC Low viscosity / flowable GIC Condensable GIC / High Viscosity GIC New fluoride releasing GIC Fluoride charged GIC Low pH ‘SMART’ MATERIALS
  76. 76. Bioactive glass Fibre-reinforced GIC Giomer Hainomer Amalgomer
  77. 77. Proline containing GIC CPP-ACP containing GIC Zirconia cotaining GIC Nano Bio ceramic modified GIC Chlorhexidine impregnated GIC Calcium Aluminate GIC
  79. 79. COMPOSITION • Compomers are essentially a one – paste system containing ion leachable glass & polymerizable acidic monomers with functional groups of polyacrylic acid & methacrylates in 1 molecule. • NaF and some other fillers are also present for additional F release. • There is no water in the formulation. • Glass particles are partially silanated to ensure bonding.
  80. 80. SETTING REACTION Setting reaction occurs in 2 stages • Stage 1: In contrast to RMGIC, a typical composite resin network around filler particles forms on light activation • Stage II : occurs over 2-3 months where by water from the saliva gets absorbed and initiates a slow acid base reaction with formation of hydrogels within the resin and low level fluoride release.
  81. 81. • Definition: Compomer can be defined as a material that contains both the essential components of GIC but at levels insufficient to promote the acid –base curing reaction in the dark • Compomer is a combination of the word ‘comp’ for composite “omer” for ionomer. • Though introduced a type of GIC, it became apparent that terms in of clinical use and performance it is best considered as a composite
  82. 82. PROPERTIES • ADHESION: to tooth requires acid –etching as acid base reaction for ion exchange which requires water does not occur for some time after placement. Bond strengths achieved usually approach the typical resin bonding systems. It is = 18-24Mpa • FLUORIDE RELEASE: is limited. It is significantly less than Type II or RMGIC. F release usually starts after about 2-3 months; it peaks initially and then falls rapidly • PHYSICAL PROPERTIES: fracture toughness, flexural strength and wear resistance are better than GIC but less than composite.
  83. 83. INDICATIONS • P& F sealant • Restoration of primary teeth, class III and V lesions along with cervical abrasions and erosions and intermediate restorations • Bases for composites, liners • Small core build ups • Filling of pot holes & undercuts in old crown preparations • Root surface sealing
  84. 84. • CONTRAINDICATIONS • Class IV lesions • Conventional class II cavities • Lost cusp areas • Restorations involving large labial surface • ADVANTAGES • Superior working characteristics to RMGIC • Ease of use • Easily adapts to the tooth • Good esthetics
  85. 85. • Recently, a 2 component compomer is being marketed as a P: L system or 2 paste system meant exclusively for luting. • These are self adhesive due to the presence of water which starts off the acid base reaction. • The powder contains the glasses, fluoride & chemical / light initiators . • liquid contains the monomers, Poly acrylic acid, water and activators. These set via light chemical polymer as well acid base reaction.
  86. 86. • To summarize the differences between the three types of materials: • Fluoride Release and Rechargability GICs>RMGICs>PAMCRs • Wear Resistance PAMCRs>GICs>RMGICs • Strength PAMCRs>RMGICs>GICs • Ease of Handling PAMCRs>RMGICs>GICs • Polishability and Esthetics PAMCRs>RMGICs>GICs
  87. 87. • These are basically, purely chemically activated RMGIC with no light activation at all. • Developed mainly for luting purposes, they contain monomers and chemical initiatiors such a the benzoyl peroxide and t- amines to allow self polymerization. • It is used mainly in paediatric dentistry for cementation of stainless steel crowns,space maintainers, bands and brackets Condensable / Self hardening GIC
  88. 88. • According to j Leirskar et al 2001, the high viscosity occurs to the material by adding poly acrylic acid to the powder and finer grain size distribution. Advantages over conventional GIC’s ( A Castro & R F Feigal,2001) • Packable + Condensable • Easy placement • Non sticky • Rapid finishing can be carried out • Improved wear resistance • Solubility in oral fluids is very low
  89. 89. Indications • As a final restorative material in class I and Class II primary teeth • Geriatric restorative material for class I,II,III,IV cavities and cervical erosion • Final restorative material in permanent teeth in non stress bearing areas • Intermediate restorative material in class I and class II cavities • Sandwich restoration • Core build up material • Fissure sealing material for permanent teeth
  90. 90. Ketac Molar Aplicap GCFuji IX Capsule
  91. 91. The low viscosity/flowable GIC – • For lining, pit and fissure sealing • endodontic sealers • for sealing of hypersensitive cervical areas • These had a low P:L ratio and possessed increase flow. eg: Fuji lining LC, Fuji III and IV, Ketac – Endo.
  92. 92. 1. Fluoride charged materials: This is a 2 part material comprising of • A restorative part and • A charge part • The restorative part is used is the usual way. When the first burst of fluoride is expended, the material is given a fluoride charge using the second part
  93. 93. 2.Low pH “Smart” Material • developed to enable release fluoride when the oral pH is low. • Aptly called “Smart” materials, the F release is episodic and not continuous which helps to prolong the therapeutic usefulness of the material
  94. 94. THE BIOACTIVE GLASS • This idea was developed by Hench and co in 1973. • It takes into account the fact that on acid dissolution of glass, there is formation of a layer rich in Ca and PO4 around the glass • such a glass can form intimate bioactive bonds with the bone cells and get fully integrated with the bone.
  95. 95. It is being used experimentally as • Bone cement • Retrograde filling material • For perforation repair • Augmentation of alveolar ridges in edentulous ridges • implant cementation • Infra- bony pocket correction
  96. 96. FIBER REINFORCED GIC • Incorporation of alumina fibres into the glass powder to improve upon its flexural strength • This technology called the Polymeric Rigid Inorganic Matrix Material or PRIMM developed by Dr. Lars Ehrnsford • It involves incorporation of a continuous network / scaffold of alumina and SiO2 ceramic fibres
  97. 97. ADVANTAGES •Due to the ceramic fibers there is increased depth of cure as light conduction and penetration is enhanced. •Polymerization shrinkage is reduced as resin is confined within the chambers. •There is also improved wear resistance Increase in flexural strength.
  98. 98. GIOMER • Developed by Shofu • Giomer utilizes the hybridization of GIC and composite by using a unique technology called the pre-reacted glass ionomer technology. • The fluoro aluminosilicate glass is reacted with polyalkenoic acid to yield a stable phase of GIC this pre reacted glass is then mixed with the resin. • Depending on the amount of glass which is reacted, the PRG technology can be 2 types: F- PRG = reaction of Full / entire glass S- PRG = Surface of glass Eg: Beautiful, Reactmer
  99. 99. AMALGOMERS • These are restoratives which are glass ionomer based but with the strength of amalgam. • They also provide F- release, natural adhesion to tooth structure, good compatibility and prevent shrinkage, creep, corrosion or thermal conductivity problems associated with other filling materials • They have been found to have exceptional wear characteristics, along with other advantages of GIC
  100. 100. HAINOMERS • These are newer bioactive materials developed by incorporating hydroxyapatite within glass ionomer powder. • These are mainly being used as bone cements in oral maxillofacial surgery and may a future role as retrograde filling material. • Studies have shown that they have a role in bonding directly to bone and affect its growth and developement
  101. 101. CHLORHEXIDINE IMPREGNATED GIC • To increase the anticariogenic action of GIC • Still under experimental stage. • Experiments conducted on cariogenic organisms
  102. 102. PROLINE CONTAINING GLASS IONOMER CEMENT J Prosthet Dent. 2013 Nov;110(5):408-13. doi: 10.1016/j.prosdent.2013.04.009. Epub 2013 Aug 30.ANSARI et al. • An amino acid-containing GIC had better surface hardness properties than commercial Fuji IX GIC. • This formulation of fast-set glass ionomer showed increased water sorption without adversely affecting the amount of fluoride release. • Considering its biocompatibility, this material shows promise not only as a dental restorative material but also as a bone cement with low cytotoxicity
  103. 103. CPP – ACP CONTAINING GIC • Incorporation of casein phosphopeptide-amorphous calcium phosphate into a glass-ionomer cement. Mazzaoui SA et al. J DENT RES 2003 NOV 82(11) • Incorporation of 1.56% w/w CPP-ACP into the GIC significantly increased microtensile bond strength (33%) and compressive strength (23%) and significantly enhanced the release of calcium, phosphate, and fluoride ions at neutral and acidic pH. • MALDI mass spectrometry also showed casein phosphopeptides from the CPP-ACP nanocomplexes to be released. • The release of CPP-ACP and fluoride from the CPP-ACP-containing GIC was associated with enhanced protection of the adjacent dentin during acid challenge in vitro.
  104. 104. ZIRCONIA CONTAINING GIC • Scripta Materialia volume 52, issue 2. Y.W. Gu et al. • Zirconia containing GIC – A potential substitute for miracle mix. • The diametral tensile strength of zirconia containing GIC significantly Greater than that of Miracle mix due to better interfacial bonding Between the particles and matrix. NANO BIOCERAMIC MODIFIED GIC • Acta biometerialia volume4 issue2 march 2008 MOSHAVERINIA et al • Nano hydroxyapaptite / fluorapatite particles added to FUJI II GC
  105. 105. • The experimental cements also exhibited higher bond strength to dentin after 7 and 30 days of storage in distilled water. • It was concluded that glass ionomer cements containing nanobioceramics are promising restorative dental materials with both improved mechanical properties and improved bond strength to dentin. • nanohydroxyapatite/fluoroapatite added cements exhibited higher compressive strength (177–179 MPa), higher diametral tensile strength (19–20 MPa) and higher biaxial flexural strength (26–28 MPa) as compared with the control group (160 MPa in CS, 14 MPa in DTS and 18 MPa in biaxial flexural strength).
  106. 106. Calcium Aluminate GIC •A hybrid product with a composition between that of calcium aluminate and GIC, designed for luting fixed prostheses. •The calcium aluminate component is made by sintering a mixture of high-purity Al2O3 and CaO (approximately 1 : 1 molar ratio) to create monocalcium aluminate. •The main ingredients in the powder of this hybrid cementare calcium aluminate, polyacrylic acid, tartaric acid,strontium-fluoro- alumino-glass, and strontium fluoride. The liquid component contains 99.6% water and 0.4% additivesfor controlling setting. •The calcium aluminate contributesto a basic pH during curing, reduction in microleakage,excellent biocompatibility, and long-term stability andstrength.
  107. 107. calcium aluminate GIC.
  108. 108. • References • Glass ionomer cement by Alan D.Wilson and John W. Mclean • Philips science of dental materials, 11th ed & 12th ed • Sturdevant’s Art and science of operative dentistry, Fifth edition • Craig’s Restorative dental materials, Twelfth edition • G J Mount and R W Hume Text book of Minimal intervention dentistry • Advances in Glass ionomer cement , Carel L. Davidson, J Minim Interv Dent 2009; 2 (1) • Clinical evaluation of glass-ionomer Cement restorations, Martin John TYAS J Appl Oral Sci. 2006;14(sp.issue):10-3 • Scripta Materialia volume 52, issue 2. Y.W. Gu et al • Acta biometerialia volume4 issue2 march 2008 MOSHAVERINIA et al