GLASS IONOMER CEMENT

1. GLASS IONOMER CEMENT

2. DEFINITION Glass-ionomer is the generic name of a group of materials that use silicate glass powder and aqueous solution of polyacrylic acid. (Anusavice)

3. CLASSIFICATIONS • Philips • Type I - Luting • Type II - Restorative • Type III - Liner & base • Davidson / Mjor • Conventional / Traditional GIC • Resin Modified GIC • Polyacid Modified Composites

4. According to clinical use : Type I- Luting TYPE II- Restorative Type III-Fast setting Liner/ Base Type IV- Pit & Fissure Sealant Type V- Luting for Orthodontic Purpose Type VI- Core build up material Type VII- High fluoride releasing command set GIC Type VIII-GIC for ART Type IX- Geriatric & Paediatric GIC

5. INDICATIONS LUTING CEMENT (Type 1 GIC) LINER AND BASE • As a liner to protect pulp from thermal insult • As base to replace carious dentin

6. RESTORATIVE CEMENT • Erosion/ abrasion lesions • Class III & V lesions • Restoration on primary teeth • Restoration in rampant caries cases • Laminate restorations • ART (Class I Lesions) • Micro cavity preparation • Small to medium size class I lesion • Repair of open margins around crowns and inlays

7. Pit & fissure sealant Luting of orthodontic brackets and bands Core build up Surface protection and caries stabilization (Type VII) In Endodontics Sealing the root canals Sealing and restoring the pulp chamber Repairing the perforation Rarely treating the vertical fracture of tooth

8. CONTRAINDICATIONS • Class IV lesions and fractured incisors • Large labial restoration where esthetic is of prime concern • Lost cusp area • Class II lesions where conventional cavities are prepared

9. COMPOSITION POWDER (Calcium Fluroaluminosilicate) ALUMINA (28.6%) Alumina: Silica --> 1:2 SILICA (41.9%) FLUORIDE CALCIUM FLUORIDE (15.7%) ALUMINIUM PHOSPHATE (3.8%) CRYOLITE Na+, K+, Ca2+

10. LIQUID • POLYACRYLIC ACID (40 to 50%) ( Polyacrylic: Itaconic-- > 2:1 ) • ITACONIC ACID • MALEIC ACID • TRICARBOXYLIC ACID • TARTARIC ACID(5-15%) • POLYPHOSPHATES • METAL OXIDES • WATER

11. Advantage: • Anticariogenicity • Biocompatibility • Chemical adhesion Disadvantage: • Esthetics • Solubility • Strength

12. Anhydrous Cement : • The term ‘anhydrous’ is a misnomer since the glass ionomers are water based cements and water is an essential component of all types. However, polyacrylic acid can be vacuum dried and incorporated with the glass powder. • The liquid then used can be either water or a dilute aqueous solution of tartaric acid. • On mixing, these cements have a relatively low viscosity and are particularly suitable for luting and lining purposes.

13. CLINICAL PROCEDURE (DISPENSING) STANDARDIZE POWDER IN SPOON DISPENSE LIQUID TO AVOID AIR BUBBLES

14. MIXING MIXING POWDER AND LIQUID USING PLASTIC SPATULA FOLDING TECHNIQUE FOR MIXING

15. MATRIX APPLICATION PREFORMED HAWE MATRICES SOFT TIN MATRIX

16. FINISHING & POLISHING Remove excess cement with sharp blade to reduce gross contour • After 24 hours, fine diamond with air/ water spray for gross contour • Rubber polishing points for refining • Polishing discs for glossy finish • Sealing with resin sealant or vaseline

17. RECENT ADVANCES IN GIC

18. HIGH VISCOSITY GIC Developed as an alternative to amalgam. Packable / condensable glass ionomer cements 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 .

19. Commercial Products FUJI-IX GP FUJI-IX GP FAST

20. LOW VISCOSITY GIC Also called as Flowable GIC Low P:L ratio thus increase flow. Use for lining, pit and fisure sealer, endodontic sealer and for sealing hyper sensitive cervical area. Eg: Fuji lining LC, Ketac – endo etc. Fuji lining LC Ketac-Endo

21. METAL MODIFIED GIC 1 Seed & Wilson (1980) introduced miracle mix 2 Spherical silver amalgam alloy+Type II G I C in ratio 7:1 3 Mc lean & Gasser (1985) introduced cermet Glass powder sintered to metal fillers (<5%) at 800°C 4 Minimal improvement in mechanical property • Compressive strength – 150 Mpa • Modulus of elasticity is slightly lower • KHN – 39 • Tensile strength – slightly more 6.7 Mpa • Slight increase in wear resistance. 5 Fluoride release • Max for miracle mix (3350µg, 4040µg) • Min for cermet (200µg, 300µg)

22. Indications: Class I cavities in primary teeth Core build up material Lining of class II amalgam restorations Root caps for teeth under over dentures As a preventive restoration Contraindications: Anterior restoration In areas of high occlusal loading Advantages: Ease for placement Adhesion to tooth structure and anticariogenic potential Crown cutting can be done immediately Increased wear resistance Disadvantages: Esthetically poor Tooth discoloration Rough surface

23. COMMERCIAL PRODUCTS Miracle mix Ketac Silver

24. RESIN MODIFIED GIC Objective: To overcome low early strength and moisture sensitivity 1. Defined as hybrid cement that sets partly by acid base reaction and partly by polymerization reaction (Mc Lean) 2 Materials that are modified by the inclusion of resin, generally to make the them more photo curable (Nicholson) 3. Powder – Ion leachable glass and initiators Liquid – water, Poly acrylic acid, HEMA (15-25%), methacrylate monomers. 4. Setting reaction: - Dual cure

25. Advantages • Long working time due to photo curing • Improved setting characteristics • Increase early strength • Finishing & polishing can be done immediately • Better adhesion to composite restoration • Fluoride release. • Repairable.

26. Disadvantage • Biocompatibility is controversial • More setting shrinkage leading increase microleakage and poor marginal adaptation

27. Uses • As a luting cement (FUJI PLUS Ketac-cem 3M ESPE, Fuji Cem)

28. As a liner and bases (Fuji LC) • As a pit and fissure (Vitre Bond) • Core build up material (Fuji I LC) • Retrograde filling material

29. Self hardening RM GIC • Activated purely by chemical polymerisation reaction • Contains benzoyl peroxide and T-Amines • Advantages • Ease of handling • Fluoride release • Higher compressive strength • No additional set up for light activation • Uses: • Luting of stainless steel crown, orthodontic brackets, space maintainers.

30. Low pH “Smart” Material • Releases fluoride when pH falls below the critical level • Fluoride release is episodic and not continuous

31. Bioactive glass • Introduce by Hench in 1973 • Acid dissolution of glass forms calcium and phosphate rich layers • The glass can form bioactive bonds with bone cells • Better than hydroxyapatite • Can grow calcium and phosphate rich layer in presence of calcium and phosphate saturated saliva.

32. Uses • Bone cement • Retrograde filling material • For perforation repair • Augmentation of resorbed alveolar ridge • Implant cementation • Infra bony pocket correction • Bio glass ceramic crown.

33. Fiber-reinforced Glass Ionomer Cements • Al and Sio2 fibers added to glass powder (PRIMM) • Diameter of fiber is 2µm. • Advantages: • Improved flexure strength(50Mpa) • Increased wear resistance. • Improved handling characteristics • Increased depth of cure • Reduction of polymerization shrinkage

34. GIOMERS • True hybridization of GIC and composite • Combine fluoride release and fluoride recharge of GIC with esthetic easy polish ability and strength of composite

35. Example BEAUTIFUL (SHOFU)