Glass ionomer cement with recent advancements

GIC including all recent advancements

1. GLASS IONOMER CEMENT AND ITS RECENT ADVANCEMENTS PRESENTED BY -: Dr Nadeem Aashiq MDS 1st Year 1

2. CONTENTS INTRODUCTION HISTORY AND EVOLUTION CLASSIFICATION COMPOSITION SETTING REACTION PROPERTIES INDICATIONS CONTRAINDICATIONS FLUORIDE RELEASE MANIPULATION ADVANCES IN GIC CONCLUSION

3. DEFINITION Phillips’ Science of DENTAL MATERIALS 12 th edition 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-12 th edition ) Definition of glass ionomer cement : A cement that consists of a basic glass & an acidic polymer which sets by an acid-base reaction between these components. (Mclean & Wilson 1994)

4. 4

5. INTRODUCTION Phillips’ Science of DENTAL MATERIALS 12 th edition

6. ADA specification number: 96 It was named glass ionomer because, the powder is a type of glass and the setting reaction and adhesive bonding to tooth structure is due to ionic bond. Glass ionomer cement is often known as a biomimetic material, because of its similar mechanical properties to dentine. For this reason it is one of the most popular cements in dentistry. Synonyms: Poly ( alkenoate ) cement Man Made Dentin ASPA ( alumino silicate polyacrylic acid) -Textbook Of Manappalli 4 th Edition

7. HISTORY 7 Text Book Of Operative Dentistry R amya Raghu 2 nd Edition

8. CLASSIFICATION

9. According to skinners Type I – Luting Type II- Restorative Type III- Liner and base According To Mc Lean, Nicholson and Wilson (1994) Glass ionomer cement a. Glass polyalkeonates b. Glass polyphosphonates 2. Resin modified GIC 3. Polyacid modified GIC 10 Text Book Of Vimal Sikri 4 th edition

10. According to application Type I Luting cements Type II Restorative cements Type III Lining/ base cements Type IV Pit &Fissure sealants Type V Orthodontic cements Type VI Core build up cements Type VII Fluoride releasing GIC Type VIII for ART Type IX For Pediatric 11 Text Book Of Vimal Sikri 4 th edition

11. NEWER CLASSIFICATION 1) Traditional glass Ionomer Type I Luting cement Type II Restorative cement Type III Liners and Bases 2) Metal Modified GlC Miracle mix Cermet cement 3) Light Cure GIC HEMA added to liquid 4) Hybrid GIC/ Resin Modified GIC a. Composite resin in which fillers substituted with glass ionomer particle b. Pre cured glasses blended into composites Text Book Of Vimal Sikri 4 th edition

12. Representative commercial products Aquacem , Fuji I — Luting Ketac bond — Bases and liners Chem Fil , Fuji II — Restorations Vitra bond — Light cure GIC -Textbook Of Manappalli 4 th Edition

13. COMPOSITION

14. POWDER CONTAINS : 15

15. Fluoride is an essential component of the glass 16

16. 17 Fusing of silica, alumina, cryolite,fluorite , aluminium fluoride and aluminium phosphate at 1100-1500 c. for 45-120 minutes followed by rapid cooling of the melts to form stressed opal glasses. This is then ground to a fine powder of particle size 15–50µm MANUFACTURING OF POWDER

17. 18 LIQUID

18. Liquid Contains : Originally the liquid was a 50% aqueous solution of polyacrylic acid. It was very viscous and had a tendency to gel. Modern glass ionomer liquids are in the form of copolymers with itaconic acid, maleic acid and tricarboxylic acid. This poly electrolytic liquid of GIC is, thus, also called as poly alkenoic acids. Mahesh et al International Journal of Plant, Animal and Environmental Sciences

19. 20 Anhydrous Cement or water settable GIC : Consist of freeze-dried polyacrylic acid and glass powder in one bottle and water with tartaric acid in another bottle as liquid. Thus Cement has longer working time and shorter setting time -Textbook Of Manappalli 4 th Edition

20. SETTING REACTION 21 Phillips’ Science of DENTAL MATERIALS 12 th edition

21. Decomposition and Migration 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 int o aqueous phase of cement and form complexes Initially calcium complexes predominate but later Aluminium complexes are more pH and viscosity increases Gelation At critical pH and ionic conc. Precipitation of insoluble poly acrylates takes place. 22

22. Initial set occurs due to calcium polyacrylate but hardening of cement is due to slow formation of aluminium polyacrylate When cement is not fully hardened Al, Ca, F and polyacrylate ions may leach out leading to irretrievable loss of cement matrix Hardening and slow maturation 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 . Increase in strength and rigidity are associated with slow increase in cross linking. 23

23. Structure of set cement The set cement consists of unreacted powder particles surrounded by a silica gel sheath and embedded in an matrix of hydrated calcium and aluminum cross-linked poly salts. Phillips’ Science of DENTAL MATERIALS 12 th edition

24. 25  Glass composition : If the Al2O3 / SiO2 and fluoride content are higher in ratio faster the set and shorter the working time.  Particle size of the glass powder : Finer the powder, faster the set and shorter the working time.  Addition of tartaric acid: Sharpens the set without shortening the working time. FACTORS AFFECTING SETTING

25. 26 Polyalkenoic acid attacks dentine and enamel: displaces PO 4, 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. Mechanism of Adhesion

26. 27

27. 28 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 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.

28. 29 Fluoride has antimicrobial property Fluoride is used as a flux A fluoride exchange is available with the fluoride ions returning to the cement from the external application of fluoride at a later date. Thus topical fluoride application may provide a topping-up effect The fluoride release is result of :- setting reactions ion exchange process in the cement. FLUORIDE RELEASE

29. Initial release is high. But declines after 3 months. After this, fluoride release is continuous for a long period. Fluoride can also be taken up into the cement during topical fluoride treatment and released again ,thus GIC act as fluoride reservoir. DURATION OF FLOURIDE RELEASE Fundamentals of Operative Dentistry 3 rd edition, Summit

30. FLUORIDE RE-CHARGING OF GLASS IONOMERS Fluoride release exponentially declines to low levels (0.5-2.0 ppm typically) Re-charging Fluoride absorption from other sources into GIC materials for re-release later Re-charging -- occurs when F can readily diffuse from high-to-low concentrations Re-charging strategies: 1. Use daily fluoride rinses to provide F source for re-charging 2. Use F toothpastes for re-charging 3. Use topical fluorides for re-charging Fundamentals of Operative Dentistry 3 rd edition, Summit

31. CEMENT TYPE 14 DAYS 30 DAYS CERMET 200 µg 300 µg SILVER ALLOY ADMIX 3350 µg 4040 µg TYPE I GIC 470 µg 700 µg TYPE II GIC 440 µg 650 µg GIC LINER [conventional] 1000 µg 1300 µg GIC LINER [Light cure] 1200 µg 1600 µg FLUORIDE RELEASE FROM VARIOUS PRODUCTS 32

32. 33 Role of water:- Provides ion transport needed for acid base setting reaction and fluoride release. Chemicaly bound in the set complex. Provides stability to the restorative material. Provides plasticity during manipulative stage. It is the medium in which the setting reaction takes place.

33. 34

34. Sensitivity to air and moisture Exposure of the cement to water before the hardening reaction is complete, leads to loss of cations and anions which form the matrix as they can be dissolved. Thus it is very important to protect the cement surface (by applying varnish, vaseline etc.) after it is placed in the mouth. Phillips’ Science of DENTAL MATERIALS 12 th edition

35. Phillips’ Science of DENTAL MATERIALS 12 th edition

36. PROPERTIES

37. Physical properties Sets rapidly in mouth Initial compressive strength is low(150-200Mpa) but increases with time(after a year it can reach to 400Mpa) Low solubility(0.7%) Low flexural strength Low shear strength Co-efficient of thermal expansion close to that of tooth Craig’s Restorative Dental Materials(13 th edition)

38. ABRASION RESISTANCE GIC are less resistant to abrasion than composite resins but their resistance improves considerably as they mature. HARDNESS: It is less than composites. The value is 48 KHN. FRACTURE TOUGHNESS Glass Ionomer cements are much inferior to composites in this aspect Phillips’ Science of DENTAL MATERIALS 12 th edition

39. Mixing Time : 45 to 60 seconds WORKING TIME of traditional cement is 2-3 minutes. SETTING TIME: Type I: 4-5 minutes Type II: 7 minutes POLYMERIZATION SHRINKAGE: Not seen with GIC GIC sets slowly and develops less interfacial stress. Phillips’ Science of DENTAL MATERIALS 12 th edition

40. Adhesion It bonds chemically to tooth structure by chelation Bonding is due to reaction between carboxyl group of poly acid and calcium of hydroxy apatite Bonding with enamel is higher compared to dentin due to greater inorganic content Principal barrier to adhesion is water Phillips’ Science of DENTAL MATERIALS 12 th edition

41. Esthetics GIC is tooth coloured material and available in different shades Inferior to composites They lack translucency and rough surface texture Potential for discolouration and staining Phillips’ Science of DENTAL MATERIALS 12 th edition

42. Biocompatibility Glass ionomer cements are considered as biocompatible dental materials because of following reasons: Polyacrylic acid present in the liquid is a weak acid Dissociated hydrogen ions present in GIC are further bound to the polymer chains electrostatically. The long polymer chains tangle on one another, this prevents their penetration into the dentin tubules. Phillips’ Science of DENTAL MATERIALS 12 th edition

43. The postoperative sensitivity after GIC placement is usually seen with “water-mixed” forms of the GICs. This is because of low viscosity and low initial pH of these cements . Type I glass ionomer cement show more sensitivity than type II cements because of following factors: Seating of the restoration results in pressure which further increases sensitivity. Use of a low powder-to-liquid ratio mix . Luting GICs are placed over a large surface area of cut dentin. Microleakage because of early moisture contamination can result in sensitivity. Phillips’ Science of DENTAL MATERIALS 12 th edition

44. Anticariogenic properties Type II glass ionomer releases fluoride in amounts comparable to silicate cements initially and continue to do so over an extended period of time. In addition, due to its adhesive effect they have the potential for reducing infiltration of oral fluids at the cement-tooth interface, thereby preventing secondary caries. Phillips’ Science of DENTAL MATERIALS 12 th edition

45. Advantages of GIC Inherent adhesion to tooth structure Biocompatible because large sized polyacrylic acid molecules prevent the acid from producing pulpal response . Little shrinkage and good marginal seal. Anticariogenic because of fluoride release. Aesthetic . Minimal tooth preparation required hence easy to use on children. Less soluble than other cements Less technique sensitive than composite resins. Craig’s Restorative Dental Materials(13 th edition)

46. Disadvantages Brittle and low fracture resistance Low wear resistance Water sensitivity during setting phase affects physical properties and aesthetics. Some newer products release less fluoride than conventional GIC. Opaque which makes glass ionomer cement less aesthetic than composites. Not inherently radiopaque . Require moisture control during manipulation and placement Craig’s Restorative Dental Materials(13 th edition)

47. Indications Text Book Of Operative Dentistry R amya Raghu 2 nd Edition

48. 1. Restoration of permanent teeth • Class V and Class III cavities • Abrasion and erosion lesions • Root caries 2. Restoration of deciduous teeth • Class I- IV cavities • Rampant caries, nursing bottle caries 3. Luting or cementing • Metal restorations (inlays, onlays & crowns) • Veneers • Pins and Posts • Orthodontic bands and brackets

49. 4. Preventive restorations • Tunnel preparation • Pit and fissure sealant 5. Protective liner under composite and amalgam 6. Dentin substitute 7. Core build up 8. Splinting of periodontally weakened teeth

50. 9.. Other restorative techniques Sandwich technique Atraumatic restorative treatment (Fuji VIII and Fuji IX) 10. In Endodontics • Repair of external root resorption • Repair of perforation • Retrograde filling

51. Contraindications Text Book Of Operative Dentistry R amya Raghu 2 nd Edition

52. Class IV carious lesions (or) fractured incisors Lesions involving large areas of labial enamel where esthetics is of major importance. Class II carious lesion where conventional cavities are prepared, for replacement of existing amalgam restorations. Lost cusp areas.

53. MANIPULATION

54. NOZZLE TYPE POWDER AND LIQUID CLICKER DISPENSERS ENCAPSULATED DISPENSERS DISPENSING AND MIXING

55. 56 MANIPULATION

56. 57 Saliva control is an essential cement is sensitive for water loss & contamination. Saliva, sulcular fluid and gingival haemorrhage, have to be controlled during the restoration procedure. With saliva ejectors the following are generally used ISOLATION

57. 58 PREPARATION OF TOOTH SURFACE The enamel & dentin are first cleaned with pumice slurry followed by swabbing with polyacrylic acid for 10 sec. 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. then rinsing and isolation is done. PROPORTIONING & MIXING Powder & liquid ratio is 3:1 by wt. Powder & liquid is dispensed just prior to mixing. Mixing is done by plastic spatula because metal spatula may react with glass particles of gic . First increment is incorporated rapidly to produce a homogenous milky consistency. Mixing done in folding method to preserves gel structure. Finished mix should have a glossy surface.

58. 59

59. 60

60. 61 Mix should be glossy at this time which indicates unreacted polyacid on the surface. This residual acid on the surface is critical for bonding to the tooth. A dull appearance indicates inadequacy of free acid for bonding

61. 62

62. 63 Luting: powder/liquid ratio is about 1.5:1. It should string up approximately 3-4 cm from the slab. Restorative cement: powder/liquid ratio is about 3:1. It should string up approximately 1 cm from the slab and retain a glossy surface. Lining :powder/liquid ratio is about 1.5:1. It should string up approximately 4-5 cm from the slab. Correct consistency of hand mixed cement

63. 64 Initial finishing- by sharp instruments such as Bard parker blades, gold foil knifes, diamond points. Final polishing after 24 hours. Final finishing- soflex discs. FIINISHING AND POLISHING

64. DIFFERENT TYPES OF SURFACE CONDITIONERS USED ARE POLYACRYLIC ACID 25% polyacrylic acid for 10 seconds. It removes surface debris and smoothens out irregularities. It tends to open up dentinal tubules. It is the conditioner of choice as it is a part of the cement forming system. -Textbook Of Manappalli 4 th Edition

65. CITRIC ACID 50% citric acid for 5 seconds was the earliest conditioner used TANNIC ACID 25% for 30 seconds. FERRIC CHLORIDE 2% solution provides metal linkage between collagen and GIC without opening up dentinal tubules. -Textbook Of Manappalli 4 th Edition

66. 5.PROTECTION OF CEMENT AFTER SETTING Before dismissing the patient ,restoration is again coated with the protective agent to protect trimmed area. Failure to protect for first 24hrs results in weaken cement. Craig’s Restorative Dental Material 13 th edition

67. -Textbook Of Manappalli 4 th Edition

68. SANDWICH TECHNIQUE Text Book Of Operative Dentistry R amya Raghu 2 nd Edition Devolped by Mclean To combine the beneficial properties of GIC & composite Also known as layering or stratification

69. 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 enamel bonding agent & finally place the composite resin over GIC & light cure it. 70 Text Book Of Operative Dentistry R amya Raghu 2 nd Edition

70. 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. 71 Text Book Of Operative Dentistry R amya Raghu 2 nd Edition

71. In the open technique, the GI is used to replace the dentin and also fill the cervical part of the box, which results in a part of the GI being exposed to the oral environment. Use the “open sandwich” technique when there is no remaining enamel at the gingival margin In the closed technique, the dentin is covered by the GI, which is in turn completely covered by the overlaying composite. Use the “closed sandwich” technique when there is remaining enamel at the gingival margin

72. 73 MODIFIED GLASS IONOMER CEMENT

73. 74 HIGH VISCOSITY GIC Developed as an alternative to amalgam. Packable / condensable glass ionom ER. COMPOSITION : Powder: Ca,Al fluorosilicate glass Liquid: Poly acrylic acid,Tartaric acid,water and benzoic acid INDICATIONS: Molar restoration of primary teeth Intermediate restoration Core build up material For A R T ADVANTAGES : Packable or condensable Improved wear resistance Easy to use Low solubility Rapid finishing possible Decrease moisture sensitivity DISADVANTAGES : Limited life Moderately polishable Not esthetic

74. 75 LOW VISCOSITY GIC Also called as Flowable GIC Low P:L ratio thus increase flow. INDICATIONS for lining pit and fisure sealer endodontic sealer for sealing hyper sensitive cervical area.

75. 1.METAL MODIFIED GLASS IONOMER CEMENT They have improved the strength, fracture toughness and resistance to wear and yet maintained the potential for adhesion and anticariogenic property. TYPES Two methods are employed 1. Silver alloy admixed Spherical amalgam alloy powder is mixed with restorative type GIC powder (Miracle Mix). 2. Cermet Silver particles are bonded to glass particles. This is done by sintering a mixture of the two powders at a high temperature ( Ketac -Silver ). -Textbook Of Manappalli 4 th Edition

76. 77 MIRACLE MIX CERMET COMPOSITION : Powder: 8 parts of conventional GIC powder to 1 part of silver tin particles. Liquid : poly acrylic acid. Advantages : Abrasion resistance: improved. Compressive strength and fracture resistance: limited improvement. Fluoride release is more than cermet mixture. Disadvantages : quite black, poor aesthetics. Difficult to mix to the prescribed consistency by hand. Inferior to amalgam, hence limited application. COMPOSITION : Powder: 40% by wt. Microfine silver- palladium particles + glass powder (Sintered together under pressure),Titanium oxide Liquid: Poly acrylic acid . Advantages: Abrasion resistance: improved. Compressive strength and fracture resistance: limited improvement. Improved handling properties Disadvantages : Poor aesthetics. Fluoride release is less as glass particle is metal coated. Reduced adhesion to enamel and dentin

77. 2.Resin modified GIC These materials were developed to overcome some of the drawbacks of conventional GIC like 1 . Moisture sensitivity 2 . Low initial strength 3 . Fixed working times. TYPES 1 . Resin-modified glass ionomer cement (RMGI), e.g. Fuji II LC, Vitremer , Photac Fil 2 . Compomers or polyacid -modified composites (PMC), e.g. Dyract Variglass VLC -Textbook Of Manappalli 4 th Edition

78. 79 COMPOSITION : P o w d e r : f l u o r o a l u m i n o s i l i cate glass particles,initiators such as camphorquinone for light curing and/or chemical curing. Liquid: HEMA and polyacrylic acid modified with methacrylate. ADVANTAGES : Long working time due to photo curing Improved setting characteristics Decrease sensitivity to water Increase early strength Finishing & polishing can be done immediately Improved tensile strength. Better adhesion to composite restoration Increase fluoride release. DISADVANTAGES : Biocompatibility is controversial. More setting shrinkage leading increase microleakage poor marginal adaptation

79. Recent advances in Glass ionomer cement Compomers Condensable\ self-hardening GIC Fibre reinforced GIC Giomers Amalgomers Chlorhexidine impregnated GIC Proline containing GIC CPP-ACP containing GIC Zirconia containing GIC Nano bioceramic modified GIC Calcium aluminate GIC Hainomers

80. Compomer / Polycid modified composite resin 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 in terms of clinical use and performance it is best considered as a composite 1.COMPOMER

81. 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.

82. INDIC A TI O NS 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

83. CONTRAINDICATIONS Class IV lesions Conventional class II cavities Lost cusp areas Restorations involving large labial surface

84. 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

85. 87 2. CONDENSABLE/SELF HARDENING GIC purely chemically activated RMGIC with no light activation E.g. Ketac Molar Aplicap, GC Fuji IX Capsule They contain monomers and chemical initiators such as the benzoyl peroxide and t- amines to allow self polymerization ADVANTAGES Easy placement Improved wear resistance Solubility in oral fluids is very low USES : Luting purpose, cementation of stainless steel crowns space maintainers bands and brackets.

86. 88 3.FIBRE REINFORCED GIC Incorporation of alumina fibres into the glass powder - improve flexural strength. This technology is called the Polymeric Rigid Inorganic Matrix Material. ADVANTAGES : increased depth of cure reduced polymerization shrinkage improved wear resistance increase flexural strength.

87. 4.GIOMERS True hybridization of GIC and composite . But here pre-reacted GIC powder is dispersed phase within compomer . Combine fluoride release and fluoride recharge of GIC esthetic & easy polishable INDICATIONS • Class I, II, III, IV, and Class V cavities • Restoration of cervical erosion and Root caries • Laminates and core build up • Restoration of primary teeth . • Repair of fracture of porcelain and composites ADVANTAGES Good aesthetics Ease of handling Improved physical properties Decrease in acid production of cariogenic bacteria Formation of an acid-resistant layer

88. 90 5. AMALGOMERS These are ceramic reinforced glass ionomer Th e y m a t c h t h e s t r e n g t h a n d d u r a b ili t y amalgam combined with aesthetics Conventional acid base reaction of GIC ADVANTAGES : High fluoride release Good aesthetics Bond to tooth structure Excellent biocompatibility Exceptional wear characteristics, Requires minimal cavity preparation Higher compressive and diametral tensile strength

89. 6.Chlorhexidine impregnated GIC It is developed to increase the anticariogenic action of GIC . Still under experimental stage. It increases its antibacterial activity without altering its physical and mechanical properties . 7.Proline Containing Glass Ionomer Cement - 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

90. 8. CPP-ACP CONTAINING GIC I n c o r po r a t i o n o f c a s e i n p ho sp h o pe p t i d e - a m o r p h o u s calcium phosphate into a glass-ionomer cement. ACP - potential remineralising agent when used in dental application. CPP-ACP when used with fluoride: synrgistic remineralization potential. Eg. Fuji VII TM EP 92

91. 9. 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. ADVANTAGES : Ease of handling Sustained fluoride release Increased Strength and durability Hence ideal restorative material for posterior teeth, esp. in patients with high caries index Aesthetics of GIC Eliminates mercury hazards Zirconia containing GIC – A potential substitute for miracle mix.

92. 10. BIOACTIVE GLASS IONOMER CEMENTS This idea was developed by Hench 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 bone cells and get fully integrated with the bone. 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

93. Journal of Dental and Medical Sciences Volume 15, Issue 11 Ver. III (November. 2016) 11. Calcium Aluminate GIC A hybrid product with a composition between that of calcium aluminate and GIC It is designed for luting fixed prosthesis. component is made by sintering a mixture of high-purity Al2O3 and CaO (approximately 1 : 1 molar ratio) to create monocalciumaluminate . The main ingredients are calcium aluminate, polyacrylic acid, tartaric acid , strontium- fluoro - alumino -glass , and strontium fluoride. The liquid component contains 99.6% water and 0.4% additives for controlling setting . The calcium aluminate contributes to a basic pH during curing, reduction in microleakage , excellent biocompatibility, and long-term stability and strength .

94. 12. Hainomers These are newer bioactive materials developed by incorporating hydroxyapatite within glass ionomer powder. Promising future during clinical trials as a retrograde filling material. Studies have shown – Their role in bonding directly to bone and supports its growth and development biomineralization. 96

95. NANOIONOMER Phillips’ Science of DENTAL MATERIALS 12 th edition

96. CONCLUSION Many years have passed by since the glass ionomer cement was first invented and it has been a popular material from the time it was introduced into the market. Even though the stronger and more esthetic materials were available, glass ionomer restorations still remained the choice of many practitioners because they satisfy many of the characteristics of ideal cement. 98

97. REFERENCES Sturdevant’s The art and science of Operative dentistry 5 th Edition Ramya Raghu Clinical Operative Dentistry Principles and practice second edition Phillips’ Science of DENTAL MATERIALS 12 th edition Journal of Dental and Medical Sciences Fundamentals of Operative Dentistry 3 rd edition, Summit Text Book Of Vimal Sikri 4 th edition Craig’s Restorative Dental Material 13 th edition 99