Glass ionomer Cement.pptx

Glass ionomer cement (GIC) is a self-adhesive restorative material. It is a mixture of glass and an organic acid.

1. GLASS IONOMER CEMENT

2. CONTENTS INTRODUCTION HISTORY CLASSIFICATIONS COMPOSITION MANIPULATION SETTING REACTION PROPERTIES ADVANTAGES & DISADVANTAGES INDICATIONS & CONTRAINDICATIONS MODIFICATIONS EEFECT OF WATER ON CEMENT SURFACE CONDITIONING RECENT ADAVANCES

3. INTRODUCTION Cement—Substance that hardens from a viscous state to a solid state to join two surfaces; for dental applications, cements act as a base, liner, filling material, or adhesive to bind devices and prostheses to tooth structures or to each other. Glass ionomer cement (conventional GIC)—A cement that hardens following an acid-base reaction between fluoroaluminosilicate glass powder and an aqueous-based polyacrylic acid solution. ADA specification number: 96 PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

4. HISTORY First announced by Wilson and Kent in 1972. The first GIC lacked workability and hardened slowly. Eventually Kent et al, found a glass that was high in fluoride and termed it as ASPA-I ( aluminosilicates polyacrylates ). In 1972, Wilson and Crisp discovered that tartaric acid modified the cement which was termed as ASPA-II and was used mainly for Class III restorations.

5. CLASSIFICATIONS

6. According to clinical use

7. COMPOSITION SILICA (SiO 2 ) 29% ALUMINA (Al 2 O 3 ) 16.6% ALUMINIUM FLUORIDE 5.3% CALCIUM FLUORIDE 34.2% SODIUM ALUMINIUM FLUORIDE 5% ALUMINIUM PHOSPHATE 9.9% RADIO-OPACIFIERS (lanthanum, barium, strontium) POLYACRYLIC ACID 45% WATER 50% ITACONIC ACID, MALEIC ACID 5% TARTARIC ACID POWDER LIQUID PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

8. SURFACE CONDITIONING Treatment of surface was first introduced by Mclean and Wilson in 1977 and they termed it as surface conditioning. Dentin conditioning prior to placement of GIC is done primarily to remove the smear layer. Advantages: GIC is better able to wet the dentin surface Cement bonds to dentin and not to the smear layer. It promotes ion exchange Increases surface energy. Different acids used are: 10% citric acid, 3% hydrogen peroxide, Tannic acid 25%,10% EDTA A, Prepared dentin surface showing the presence of the smear layer. B, After cleansing with polyacrylic acid, the smear layer is removed PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

9. MANIPULATION

10. SETTING REACTION

11. MECHANISM OF ADHESION Attributed to two inter-related phenomena, namely: Micromechanical interlocking caused by glass- ionomers being self-etching due to the polyacid component. True chemical bonding: This involves ionic bonds being formed between the carboxylate groups on the polyacid molecules and calcium ions in the tooth surface. Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the Mechanical Properties of Glass- Ionomer Dental Cements: A Review Interfacial ion-exchange layer formed between tooth surface (above) and glass- ionomer cement (below).

12. EFFECT OF WATER ON CEMENT Incorporation of water with glass- ionomers is associated with increase in the translucency of the cement. Exposure of cement to saliva causes the surface to soften as the vital cement forming ions are lost. Loss of unbound water causes an unsightly chalky appearance as microscopic cracks develop in the drying surface. To prevent this, it is important to protect the cement by covering it with an appropriate varnish or petroleum jelly. Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the Mechanical Properties of Glass- Ionomer Dental Cements: A Review

13. PROPERTIES Flexural strength( Mpa ) 25 Hardness ( Knoop hardness number) 48 Elastic modulus( Gpa ) 3.5-9 Fracture toughness ( Mpa /m) 0.88 Compressive strength( Mpa ) 93-226 Fluoride release (mg) 14 days 30 days 1000 1300 Tensile strength( MPa ) 3.9-8.3 Wear (volumetric change- cm 3 ) 6.0 Shrinkage(% Vol ) 3 pH 0.9 – 1.6 Film thickness(mm) 18-35 Solubility (wt%) 0.08-1.5 Setting time 1-9 Pulpal response Mild

14. Fluoride release • The influence of fluoride action is seen for at least 3 mm around the glass ionomer restoration. • Released for a sustained period of 18 months • Thickly mixed cements release more flouride than thinly mixed ones. • Fluoride release is restricted by sodium and to some extent by calcium content. PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

15. Biocompatibility Pulp response to GIC is favorable. Freshly mixed cement has an acidic pH 0.9 – 1.6. Used to protect mechanical/ traumatic exposure of healthy pulp Glass ionomer cement showed greater inflammatory response than ZOE but less than Zinc phosphate cement. 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. PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

16. 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. Durability Affected by: • preparation of the cement • protection of restoration • Variable conditions of mouth Failure rate depends on clinician’s skill than inherent quality of the material. PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

17. WORKING TIME & SETTING TIME It sets rapidly in the mouth 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. Applied Dental Materials (9 th Edition) John F. McCabe

18. INDICATIONS Erosion/ abrasion lesions Restoration of deciduous teeth Sealing and filling of occlusal pits and fissures Restoration of class III lesions, preferably using a lingual approach with labial plate intact Occlusal approach (tunnel preparation) Core build-up Other indications: Repair of defective margins in restorations Minimal cavity preparations .

19. USE IN ENDODONTICS Seal root canals Perforation repair Restore pulp chamber Repair vertical fracture GIC was used because of : • Its capacity to bond which enhances seal & reinforce the tooth • Its good biocompatibility, which would minimize irritation to periradicular tissues • Its F release, which imparts an anti microbial effect to combat root canal infection

20. CONTRA-INDICATIONS Class IV carious lesions Fractured incisors Class II carious lesions where conventional cavities are prepared. Replacement of existing amalgam restorations Lesions involving large areas of labial enamel Lost cusp areas

21. MODIFICATIONS

22. Water Hardening Cements / Anhydrous Cements To solve the problems associated with the instability of polyacrylic acid, copolymer of acids were introduced which was stable in water. In 1973 Wilson and Kent described the use of polyacrylic acid in dry form blended with glass powder. Liquid consisted of water or an aqueous solution of tartaric acid. This was termed as ASPA V by Prosser et al 1984. Advantages: Developed very low viscosity in early mixing stages. Rapid set at minimal temperature. Easy manipulation. Excellent shelf life. Applied Dental Materials (9 th Edition) John F. McCabe

23. Products of this type include Chelon-Fil (3M ESPE) Nonencapsulated forms of Ketac-Cem (3M ESPE) and Ketac -Bond (3M ESPE) Applied Dental Materials (9 th Edition) John F. McCabe

24. METAL MODIFIED GIC MIRACLE MIX / SILVER ALLOY ADMIXED GIC Sced and Wilson in 1980 incorporated spherical silver amalgam alloy into Type II GIC powder in a ratio of 7:1. Particle size of silver is 3 – 4μm PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

25. Properties of Metal Modified GIC Higher strength. Increased flexural strength. Increased resistance to abrasion. Increased fracture resistance. Low thermal conductivity. Coefficient of thermal expansion same as dentine. Disadvantages • Poor resistance to abrasion • Resistant to burnishing • Poor aesthetics PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

26. GLASS CERMET 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 μ m. 5%titanium dioxide is added to improve esthetics. It has excellent handling characteristics. Craig’s Restorative dental materials, Twelfth edition

27. 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. 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 PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

28. Composition • Powder: Ion leachable fluoroaluminosilicate glass particles along w ith camphorquinone as initiator. • Liquid : water & polyacrylic acid modified with 2-hydoxyethyl methacrylate (HEMA) monomers. • The HEMA content is around 15-25% and water content is low to accommodate the polymerizable ingredients. Properties Esthetics : definite improvement in translucency as the monomer brings the refractive index of the liquid close to that of the glass particle. Fluoride release : lining version shows higher F release PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

29. Strength : The diametrical tensile strength is much higher but compressive strength and hardness is lesser. Adhesion: to tooth is reduced whereas adhesion to composites is increased. Micro leakage : A higher degree is seen due to polymerization shrinkage. Water sensitivity is considerably reduced. The biocompatibility is controversial and precautions such as placing calcium hydroxide in deep preparations should be taken. The transient temperature rise during setting is also a concern. PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

30. CONDENSABLE / SELF HARDENING GIC This is a high viscosity GIC launched in early 1990’s. These GICs contain smaller glass particle sizes and use a higher P/L ratio, yielding greater compressive strength. They exhibit excellent packability for better handling characteristics. These glass ionomers are particularly useful for ART. ADVANTAGES • Easy placement • Non sticky • Improved wear resistance • Solubility in oral fluids is very low PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

31. CALCIUM ALUMINATE GIC A hybrid product with a composition between that of calcium aluminate and GIC, designed for luting fixed prostheses. The main ingredients in the powder are calcium aluminate , polyacrylic acid, tartaric acid,strontium fluoro - alumino -glass, and strontium fluoride. The calcium aluminate contributes to a basic pH during curing, reduction in microleakage , excellent biocompatibility, and longterm stability and strength. PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

32. RECENT ADVANCES

33. COMPOMER Compomer is a polyacid -modified composite made by incorporating glass particles of GIC in water-free polyacid liquid monomer with appropriate initiator. Compomer restorative materials require a dentin-bonding agent prior to their placement because they do not contain water. PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

34. ADVANTAGES • Superior working characteristics • Ease of use • Easily adapts to the tooth • Good esthetics 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. PHILIPS’ SCIENCE OF DENTAL MATERIALS (12 TH EDITION)

35. LOW VISCOCITY/ FLOWABLE GIC It is mainly used as lining, pit and fissure sealing, endodontic sealers, sealing of hypersensitive cervical areas, and it has increased flow.

36. BIOACTIVE GLASS Developed by Hench and colleagues in 1973, this material considers the fact that on acid dissolution of glass, there is formation of a layer rich in calcium and phosphate around the glass, such a glass can form intimate bioactive bonds with bone cells and get fully integrated with the bone. It is used in retrograde filling material, for perforation repair, augmentation of alveolar ridges in edentulous ridges, implant cementation, and infra-bony pocket correction.

37. GIOMER Developed by Shofu . Giomer is a fluoride-releasing, resin-based dental adhesive material. It 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 which is then mixed with the resin. Applied Dental Materials (9 th Edition) John F. McCabe

38. 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. After 1 and 7 days of setting, the nanohydroxyapatite / fluoroapatite added cements exhibited higher compressive strength (177-179MPa), higher tensile strength (19-20MPa) and higher flexural strength (26-28MPa). Cellulose, silks fiber and flax fiber have been employed in designing biomaterials for medical applications. Moshaverinia A, Ansari S, Moshaverinia M, Roohpour N, Darr JA, Rehman I. Effects of incorporation of hydroxyapatite and fluoroapatite nanobioceramics into conventional glass ionomer cements

39. 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 (PRIMM) developed by Dr. Lars Ehrnsford It involves incorporation of a continuous network / scaffold of alumina and SiO2 ceramic fibres . ADVANTAGES • Due to the ceramic fibers there is increased depth of cure as light conduction and penetration is enhanced. • Polymerization shrinkage is reduced • Improved wear resistance Increase in flexural strength. Ching HS, Luddin N, Kannan TP, Ab Rahman I, Abdul Ghani NRN. Modification of glass ionomer cements on their physical-mechanical and antimicrobial properties

40. ZIRCONIA CONTAINING GIC Zirconia containing GIC – A potential substitute for miracle mix. The tensile strength of zirconia containing GIC is significantly greater than that of Miracle mix due to better bonding between the particles and matrix. Advantages Matchs the strength and durability of amalgam Sustained high fluoride release Easy mixing and handling characteristics Minimize chair time Enables ease of bulk placement Excellent resistance to abrasion and erosion Ching HS, Luddin N, Kannan TP, Ab Rahman I, Abdul Ghani NRN. Modification of glass ionomer cements on their physical-mechanical and antimicrobial properties

41. AMINO ACID CONTAINING GIC 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 . Amino acid polyelectrolytes including proline are promising additives to GICs polyacids . Ching HS, Luddin N, Kannan TP, Ab Rahman I, Abdul Ghani NRN. Modification of glass ionomer cements on their physical-mechanical and antimicrobial properties

42. CHLORHEXIDINE IMPREGNATED GIC It provides a wide spectrum of activity against oral pathogen such as Gram positive bacteria For clinical use of GIC with CHX, the best option is the addition of CHX at a concentration of 0.5%, since this combination increased the antibacterial activity without changing the physical-mechanical properties of the material. However, the antimicrobial agents have extended the setting time and weaken the compressive strength of GICs. Other antimicrobials that can be used are triclosan , Chloroxylenol , boric acid and thymol , benzalkonium chloride and chitosan . Ching HS, Luddin N, Kannan TP, Ab Rahman I, Abdul Ghani NRN. Modification of glass ionomer cements on their physical-mechanical and antimicrobial properties

43. GIC WITH ANTIBIOTICS Incorporation of low quantity antibiotics into glass ionomer cement for use with ART approach. When conventional GIC was added with 1.5, 3.0 and 4.5% of ciprofloxacin, metronidazole and minocycline it was effective for inhibiting S. Mutans A GIC with was chosen because of good preliminary laboratory results and its possible use for the treatment of caries in primary teeth. The combination has shown biocompatibility and an antibacterial effect in laboratory. Ching HS, Luddin N, Kannan TP, Ab Rahman I, Abdul Ghani NRN. Modification of glass ionomer cements on their physical-mechanical and antimicrobial properties

44. GLASS CARBOMER This is a novel commercial material of the glass- ionomer type which has an enhanced bioactivity . It is manufactured by GCP Dental of the Netherlands. The components are as follows: A glass powder that has been washed by strong acid A silicone oil comprising a polydimethylsiloxane , which contains hydroxyl groups. A bioactive component, which also behaves as a secondary filler The glass contains strontium, and also high amounts of silicon, as well as a small amount of calcium and comparable amounts of aluminium , phosphorus and fluoride. Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the Mechanical Properties of Glass- Ionomer Dental Cements: A Review.

45. NANOTECHNOLOGY IN GIC Nanotechnology involves the use of systems, modifications, or materials that have the size in the range of 1–100nm. Recent studies have suggested that incorporation of nano-sized particles or “nanoclusters” can improve the mechanical properties of dental restorative materials such as resin composites.

46. 1. POWDER-MODIFIED NANO GIC Described for the first time by De Caluwé   et al. , it involves doping conventional GICs with nano-sized glass particles, which can decrease the setting time and enhance the compression strength and elastic modulus. The main advantages of decreasing setting times of direct restorative materials are enhanced ease of handling and manipulation.

47. 1. POWDER-MODIFIED NANO GIC Modification using nano-apatite : Addition of nano-apatite or nano- fluoroapatite to the powder component of conventional GIC has a positive impact on the compressive, tensile, and flexural strengths of the set cement after being stored in distilled water for 7 days. Modification with nano-sized hydroxyapatite, calcium fluoride, and titanium dioxide particles : It has been recently reported by Gu  et al . that the combined incorporation of HAp and zirconia ( HAp /ZrO 2 ) at concentrations of 4% volume to the GIC powder can improve the mechanical properties of the set GIC.

48. 2. NANO-FILLED RESIN-MODIFIED GIC Resin-modified GICs also have a polymer resin component, which usually sets by a self-activated (chemically cured) or light-activated polymerization reaction. To develop the mechanical properties of a resin composite with the anticaries potential of GICs, these were developed. However, compared to composites, resin-modified GICs have reduced mechanical properties, including brittleness and inferior strength along with aesthetics.  To overcome these drawbacks, there have been attempts to incorporate nano-sized fillers and bioceramic particles to RMGICs.

49. Properties of nano-RMGICs Bonding of nano-RMGIC with tooth structure: More ionic bonding with tooth rather than micromechanical retention, much akin to conventional GICs. Mechanical and physical properties of nano-RMGICs: Poor flexural strength and fatigue limit in commercially available nano-RMGICs. Perform the worst when mechanically tested on acid challenge. Acidic environment may jeopardize the long-term survival rate of nano-RMGICs. Surface mechanical properties of RMGICs: The aesthetic properties of dental resin composite materials have been radically improved. Fluoride release from nano-ionomers: Slightly increased fluoride release from nano-RMGICs at a pH of 4.

50. CONCLUSION Among all the dental restorative materials, GICs are found to be the most cariostatic and has antimicrobial properties due to release of fluoride, which helps in reducing demineralization, enhance remineralization and inhibit microbial growth. However, up to date none of the restorative material available can be regarded as ideal and perfect.

51. REFERENCES Philips science of dental materials 12th edition Applied Dental Materials (9 th Edition) John F. McCabe Craig’s Restorative dental materials, Twelfth edition Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the Mechanical Properties of Glass- Ionomer Dental Cements: A Review.  Materials (Basel) . 2020;13(11):2510. Published 2020 May 31. Ching HS, Luddin N, Kannan TP, Ab Rahman I, Abdul Ghani NRN. Modification of glass ionomer cements on their physical-mechanical and antimicrobial properties.  J Esthet Restor Dent . 2018;30(6):557-571. Moshaverinia A, Ansari S, Moshaverinia M, Roohpour N, Darr JA, Rehman I. Effects of incorporation of hydroxyapatite and fluoroapatite nanobioceramics into conventional glass ionomer cements (GIC).  Acta Biomater . 2008;4(2):432-440. doi:10.1016/j.actbio.2007.07.011