- Slides: 35
GLASS IONOMER CEMENT
DEFINITION Glass-ionomer is the generic name of a group of materials that use silicate glass powder and aqueous solution of polyacrylic acid. (Anusavice)
CLASSIFICATIONS • Philips ▫ Type I - Luting ▫ Type II - Restorative ▫ Type III - Liner & base • Davidson / Mjor ▫ Conventional / Traditional GIC ▫ Resin Modified GIC ▫ Polyacid Modified Composites
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
INDICATIONS LUTING CEMENT (Type 1 GIC) LINER AND BASE ▫ As a liner to protect pulp from thermal insult ▫ As base to replace carious dentin
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
• 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
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
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+, Ca 2+
LIQUID ▫ POLYACRYLIC ACID (40 to 50%) ( Polyacrylic: Itaconic-- > 2: 1 ) ▫ ITACONIC ACID ▫ MALEIC ACID ▫ TRICARBOXYLIC ACID ▫ TARTARIC ACID(5 -15%) ▫ POLYPHOSPHATES ▫ METAL OXIDES ▫ WATER
Advantage: • Anticariogenicity • Biocompatibility • Chemical adhesion Disadvantage: • Esthetics • Solubility • Strength
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.
CLINICAL PROCEDURE (DISPENSING) STANDARDIZE POWDER IN SPOON DISPENSE LIQUID TO AVOID AIR BUBBLES
MIXING POWDER AND LIQUID USING PLASTIC SPATULA FOLDING TECHNIQUE FOR MIXING
MATRIX APPLICATION PREFORMED HAWE MATRICES SOFT TIN MATRIX
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
RECENT ADVANCES IN GIC
HIGH VISCOSITY GIC Developed as an alternative to amalgam. Packable / condensable glass ionomer cements INDICATIONS: Molar restoration of primary teeth ADVANTAGES: Packable or condensable Intermediate restoration Core build up material For A R T DISADVANTAGES: . Improved wear resistance Easy to use Low solubility Rapid finishing possible Decrease moisture sensitivity Limited life Moderately polishable Not esthetic
Commercial Products FUJI-IX GP FAST
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
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)
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
COMMERCIAL PRODUCTS Miracle mix Ketac Silver
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 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
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.
Disadvantage • Biocompatibility is controversial • More setting shrinkage leading increase microleakage and poor marginal adaptation
Uses • As a luting cement (FUJI PLUS Ketac-cem 3 M ESPE, Fuji Cem)
• As a liner and bases (Fuji LC) • As a pit and fissure (Vitre Bond) • Core build up material (Fuji I LC) • Retrograde filling material
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.
Low p. H “Smart” Material • Releases fluoride when p. H falls below the critical level • Fluoride release is episodic and not continuous
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.
Uses • Bone cement • Retrograde filling material • For perforation repair • Augmentation of resorbed alveolar ridge • Implant cementation • Infra bony pocket correction • Bio glass ceramic crown.
Fiber-reinforced Glass Ionomer Cements • Al and Sio 2 fibers added to glass powder (PRIMM) • Diameter of fiber is 2µm. • Advantages: ▫ Improved flexure strength(50 Mpa) ▫ Increased wear resistance. ▫ Improved handling characteristics ▫ Increased depth of cure ▫ Reduction of polymerization shrinkage
GIOMERS • True hybridization of GIC and composite • Combine fluoride release and fluoride recharge of GIC with esthetic easy polish ability and strength of composite
Example BEAUTIFUL (SHOFU)