Dental Cements II PDF

1 Classification of Cements ž Acid-base reaction cements Ø Based on phosphoric acid Ø Based on organometallic chelate compound Ø Based on polyalkenoic acid (polyacrylic acid) ž Resin-based cements Ø Composite resin Ø Adhesive resin Ø Compomer 2  Ø...

1 Classification of Cements ž Acid-base reaction cements Ø Based on phosphoric acid Ø Based on organometallic chelate compound Ø Based on polyalkenoic acid (polyacrylic acid) ž Resin-based cements Ø Composite resin Ø Adhesive resin Ø Compomer 2  ØBased on organometallic chelate compound Zinc Oxide Eugenol: ZOE (ZOE) Eugenol ZnO Reinforced ZOE (RZOE) Eugenol ZnO, Polymer, Rosin ZOE-EBA (EBA) Eug, EBA ZnO, Al2O3, Rosin HV-EBA (HV-EBA) HV, Eug ZnO, Al2O3, Rosin ØBased on phosphoric acid Zinc Phosphate (ZP) H3PO4 / H2O, ZnO Silicate (SC) H3PO4 / H2O, F-Al-Silicate glass Zinc Silicophosphate (ZSP) H3PO4 / H2O, ZnO, F-Al-Silicate 3 ØBased on polyalkenoic acid Polycarboxylate (PC) PAA / H2O ZnO Glass Ionomer: Conventional (GI) PAA / H2O F-Al-Silicate Glass Resin-Modified (RMGI) “ + HEMA, … F-Al-Silicate Glass ØResin-based cements Compomer (CM) (Monomers) F-Al-Silicate Glass Composite (with DBS) (Monomers) (Silicate glass fillers) 4 Acid-base reaction cements ž ACID + excess BASE → residual BASE + insoluble SALT ž Liquid + excess powder → residual powder + matrix ž The residual powder and matrix must be insoluble in oral fluids 5  Zn ZOE Polycarboxylate ZnPO4 Eugenol ZnO, MgO Phosphoric Polyacrylic Acid Acid Fluoroaluminosilicate glass (FAS) Silicate GIC 6 INSTRUMENT SET UP 7 Cement Types žType I : Luting/Cementation žType II : Restorative žType III: Base/Liner 8 Cements based on phosphoric acid ž Zinc phosphate — the oldest of the cements — long history of success — supplied as a powder-liquid system ž Silicatecements ž Silicophosphates 9 Zinc Phosphate Cement 1. Composition Composition Powder ZnO (Principal constituent) MgO, SiO2, Bi2O3 Liquid Aq. Phosphoric acid (30 – 40% H2O) Zn ± Al phosphates as buffer to slow setting reaction during mixing 10 Zinc Phosphate Cement 2. Setting reaction o 3Zn + 2H3PO4 Zn3(PO4) 2 + H2O o Surface of ZnO dissolved by acid to give insoluble phosphate 11 ZnO ZnO Zn+ ZnO Zn+ Zinc aluminophosphate gel 12 o The set cement heterogeneous – a core of unreacted ZnO in a matrix of Zn Phosphate o Exothermic reaction o Initial low acidity (pH 3-4) – may irritate pulp Unreacted ZnO Unreacted ZnO Unreacted ZnO 13 Zinc Phosphate Cement 3. Manipulation § Factors involved in the setting reaction ü Powder/liquid ratio ü Rate of addition of powder to liquid ü Presence of moisture ü Temperature 14 Zinc Phosphate Cement 3. Manipulation § Dispensed as scoops of powder and drops of liquid § Cement spatula and glass slab are used to mix the material 15 Zinc Phosphate Cement 3. Manipulation § Consistency depends on the intended clinical use: thin mix (low P/L) for luting thicker mix (higher P/L) as base 16  4 5 2 7 3 6 1 8 17 Zinc Phosphate Cement 3. Manipulation § Setting reaction is exothermic….. D Heat accelerates the setting rate § Important to dissipate this heat… C Incremental incorporation of powder into liquid C Slow mix over large area of chilled glass slab F Cooled glass slab absorbs the heat given off 18 Zinc Phosphate Cement 4. Properties A. Low film thickness – 25 - GIC, ZnPO4 § Set cement is opaque 67 Zinc Polycarboxylate Cement 5. Uses § Base § Final cementation (luting) ØCrowns ØBridges ØPosts 68 Polycarboxylate Cement 69 Zinc Polycarboxylate Cement 6. Advantages v Kind to the pulp v Chemical adhesion 7. Disadvantages v Short working time v2.5 minutes 70 Zinc Polycarboxylate Cement ž Powder contains up to 4% stannous fluoride ž Does not have anti-cariogenic properties ž Approximately 10% of what glass ionomer cement (GIC) releases 71  Zn ZOE Polycarboxylate ZnPO4 Eugenol ZnO, MgO Phosphoric Polyacrylic Acid Acid Fluoroaluminosilicate glass (FAS) Silicate GIC 72 73 74 Glass Ionomer Cement 75 Outline ž Glass ionomers — Composition — Properties — Classification ž Compomers — Composition — Properties 77  Traditional Cements Phosphoric acid Polyacrylic acid Zinc oxide Zinc Phosphate Polycarboxylate Aluminosilicate Silicate Glass Ionomer glass 78 DEVELOPMENT ž United Kingdom — Wilson and Kent 1972 ž ASPA — First commercial product — Alumino-silicate polyacrylic acid — Combined benefits ○ Silicates — Translucency, fluoride release ○ Polycarboxylates — Adhesion, biocompatibility 79 Early Problems ž Poor esthetics — Rough surface ž Prolonged setting reaction ž Poor wear resistance ž Vulnerable to hydration extremes ž Handling difficulties 80 Modifications ž Refined formulation — Addition of tartaric acid — More reactive acids ž Improved packaging ž Metal modification ž Addition of resin 81 Advantages ž Inherent (chemical) adhesion to tooth structure ž Fluoride release ž Coefficient of thermal expansion (CTE) similar to tooth structure ž Biocompatible 82 Disadvantages ž Sensitive to moisture and desiccation ž Low fracture toughness ž Low flexure strength ž Low wear resistance ž Relatively poor esthetics 83 Indications ž Direct restorative — Class V — Root caries — Class III — Pediatric dentistry ○ Resin-modified version — Tunnel preparations — Atraumatic restorative treatment (ART) 84 TUNNEL PREPARATION 85 Indications ž Luting agents ž Bases (Liners) ž Caries control ž Core block-out ž Occlusal sealant 86 Contraindications ž Stress-bearing areas in permanent teeth — Class I, II and IV 87 Basic GIC Types ž Conventional GIC — Traditional acid-base reaction ž Resin-modified (RMGIC) — Acid-base reaction — Light and/or chemical cure 88 Conventional GIC ž Composition — Powder ○ Ion-leachable calcium aluminofluorosilicate glass — Liquid ○ Copolymers of acrylic acid and/or ○ Water — Copolymers freeze-dried, placed in powder - maximize shelf-life 89 Conventional GIC ž Ion-leachable glass — Silicon dioxide — Aluminum oxide — Calcium fluoride — Aluminum phosphate — Sodium fluoride — Aluminum fluoride 90 Conventional GIC ž Polyacids — Acrylic — Maleic — Itaconic — Tricarboxylic acid ž Tartaric acid — Improves handling — Extends working time — Sharpens set — Increases strength 91 Setting Reaction (conventional) Complex acid-base reaction Glass (basic) + polyacid Forms salt hydrogel Fluoroaluminosilicate Glass H2O reaction medium Three phases COO- H+ Ion-Leaching Phase Hydrogel COO- H+ COO- H+ Polysalt-Gel Phase Polyacrylic Acid 92 Setting reaction conventional ž Ion-leaching phase — Acid attack on glass ○ H+ from polyacid H+ COO - — Al , Ca , F migrate and +3 +2 - COO - M n+ form complexes Mn+ H+ — Hydrogel forms around glass particles H + COO- Mn+ — Ca+2 predominate early — NaF formed ○ Not native of matrix ○ Physical properties not affected by depletion of F 93  Setting Reaction (conventional) Hydrogel Phase Ca+2 & Al+3 polysalts COOH crosslink polymer chains COOCOO - - COO M - Causes viscosity increase 1+ M3+COO - COOH M2+ COO- & hardening COO- - COO Poor physical properties Very susceptible to moisture COOH COOH Protect with matrix, bonding agent 94 Setting reaction (Conventional) ž Polysalt-Gel Phase — Slow maturation of matrix ○ Al+3 polyacrylate polymers predominate ○ Stronger, less soluble ○ Saturation may require 6 months–1 yr ž Later stage susceptible to dehydration — Protect with bonding agent 95  Setting time 2.5-8 minutes H+- COO- n+ COO M (luting); 2-6 minutes M H+ (restorative) n+ Fluoroaluminosilicate Glass H+COOM - n+ Conventional COO- H+ Glass-Ionomer Setting Reaction COO- H+ COO- H+ COOH COO- Ca2+ Polyacrylic Acid COO- COO - COO- M COO - Toot M COO h 3+ - 1+ COOH M2+ COO- COO- - COO- 2+ COO Ca COO- COOH COOH 96 97 Resin-Modified Glass Ionomers First developed as liners Modified light- and/or chemically-activated methacrylate side chains On polyacrylic-acid molecules Free in solution HEMA Total set resin 4.5–6% 98 Resin-Modified Glass Ionomer Attempt to combine benefits Attempt to reduce Glass ionomer Glass ionomer Fluoride release Hydration sensitivities Adhesion Delayed set Composite resin Poor early strength Strength Composite Esthetics Polymerization shrinkage Microleakage Recurrent caries Glass Ionomers RMGI Compomers Composites 99 Resin-Modified Glass Ionomer Composition Powder Ion-leachable glass Liquid Initiators Copolymers of acrylic acid Methacrylate groups grafted and/or HEMA And/or Water Copolymers freeze-dried, placed in powder Maximize shelf-life 100 Setting Reaction (RMGI) Traditional glass-ionomer Poly-HEMA acid-base reaction COO- COO- COO- Proceeds more slowly M1+ COO- M3+ COOH M2+ COO- Free-radical polymerization COO- COO- Similar to composites COOH COOH Poly-HEMA Light initiated Chemical Cross-linked resin-reinforced matrix 101 Free-Radical Polymerization Visible-light Photoinitiator Camphorquinone Camphorquinon e Most common Absorbs blue light Initiator reacts with amine activator Benzoyl Chemical Peroxide Mix separate pastes O O O O Benzoyl-peroxide initiator Tertiary-amine activator CH HEMA 3 Forms free radicals H C=C-C-O-CH -CH -OH 2 2 2 Initiates addition polymerization O Methacrylates Grafted and/or free 102  HEMA CH3 HEMA H2C=C-C-O-CH2-CH2-OH H+ COO- Resin-Modified COO- Mn+ O Glass-Ionomer H+ Mn+ HEMA Setting Reaction HEMA H+ COO- Mn+ Fluoroaluminosilicate Glass COO- H+ COO- H+ Poly-HEMA COO- H+ COO- Ca2+ Polyacrylic Acid COO- COO- COO- Tooth COO- M1+ M3+ COO- COOH M2+ COO- COO- COO- COO- Ca2+ COO- COOH COOH Poly-HEMA 103 Material-Related Variables Fluoride release Adhesion Pulpal response Physical properties 104 Fluoride Release Rapid early release from matrix F- Slow, long-term release from F- F- COO- F- particle Al3+ COO- Does not take part in matrix F- COO- formation F- F- F- Does not result in loss of physical properties F- Amount of release similar for both conventional and RMGI 105 Fluoride Release Initial burst F Initial Release Burst High early release Sustaine Recharg e d Low 1 – 2 days Levels Sustained low levels Time Fluoride reservoirs Uptake and re-release Topical fluorides Only fraction of initial F level 106 Fluoride Elevated in saliva Enhancement of remineralization Incorporated into tooth structure Effective zone around restorative margin Up to 7.5 mm in enamel Bacterial effects Metabolism Reduced acid production Reduced growth 107 Clinical Efficacy of Fluoride-Releasing Materials Equivocal Review of 28 clinical studies No conclusive, overall evidence of caries reduction Studies suggest caries reduction Xerostomic patients 108 Adhesion to Tooth Structure Conventional GI Ion exchange COO- GI – tooth substrate COO- Ca2+ Carboxyl groups of GIC COO- M3+ COO- Tooth Bond with Ca+2 of COO- hydroxyapatite COO- COO- Ca2+ Resin-modified GI COOH Ion exchange similar to conventional GI Resin-impregnated hybrid layer? Equivocal 109  Type 1 Luting Type 2 Restorative Glass Type 3 Type 4 Liner/base Pit & fissure sealant ionomer Type 5 Luting for orthodontic cement Type 6 Type 7 Core build up High Fluoride releasing Type 8 Atraumatic restorative tx Type 9 Pediatric GIC 110 Classifications Applications Type 1: Luting cements Type 2: Restorative cements Esthetic restoratives Reinforced restoratives Condensable Metal-modified Type 3: Liners, bases/sealants Chemistry Conventional GI Traditional acid-base reaction Resin-modified (RMGI) Acid-base reaction Light and/or chemical cure 111 Applications Type 1: Luting cements Type 2: Restorative cements Esthetic restoratives Reinforced restoratives Condensable Metal-modified Type 3: Liners, bases/sealants 112 Luting Cements (Type 1) Conventional Examples Ketac-Cem (3M ESPE) Fuji 1 (GC) Resin-modified (RMGI) Greater strength Less moisture sensitivity Less soluble Examples Fuji Plus and FujiCem (GC) Rely X (3M ESPE) 113 Post-Op Sensitivity Luting Cements Initial reports of sensitivity When cements were first introduced Due to low initial acidity and improper handling Clinical studies show no increase in sensitivity When properly used Conventional GI vs. Zinc Phosphate No difference Conventional GIC vs. RMGIC No difference 114 RMGI Luting Cements Hydroscopic Expansion Percent Linear Expansion 5 4.5 4 Contraindications 3.5 3 1 Hr Non-reinforced 2.5 2 1 Day all-ceramic 1.5 1 2 Mos restorations 0.5 0 -0.5 Follow Zn Phos GI Resin RMGI manufacturer’s recommendations 115 Orthodontic Luting Agents Fluoride releasing Reduced incidence of white spot lesions Bonds in moist environment Condition surface Etch optional Only light-leveling wires first 24 hrs Examples Fuji Ortho (GC) Fuji Ortho LC (GC) 116 Endodontic Obturation Fluoride releasing Radiopaque Short working time More difficult to retreat Example Ketac-Endo (3M EPSE) 117 Glass ionomer Cement ž Type I: Luting and bonding cements. ž For cementation of crowns, bridges, inlays, onlays and orthodontic appliances. ž Use relatively low powder:liquid ratio (1.5:1 to 3.8:1), leading to moderate strength only ž Fast setting with good early resistance to water ž Are radio-opaque 118 Applications Type 1: Luting cements Type 2: Restorative cements Esthetic restoratives Reinforced restoratives Condensable Metal-modified Type 3: Liners, bases/sealants 119 Esthetic Restoratives (Type 2) Conventional Examples Ketac-Fil (3M ESPE) Fuji II (GC) Glasionomer Type II (Shofu) RMGI Examples Fuji II LC (GC) Vitremer (3M ESPE) Riva Light Cure (SDI) 120 Esthetic Restoratives Case Selection High caries risk Areas of lower stress Permanent Class III & V Esthetics not paramount Pediatric dentistry RMGI version 121 Esthetic Restoratives Technique Tips Surface must be clean Remove smear layer Tooth must be moist 122 Esthetic Restoratives Conditioning Dentin Conventional GI Polyacrylic-acid conditioner Removes smear layer Cleans surface Promotes adhesion RMGI Follow manufacturer’s directions Polyacrylic-acid conditioner or adhesive 123 Esthetic Restoratives Moisture Content Sensitive to moisture levels Ion exchange in hydrated medium Desiccation Extracts water from cement Excess water Dilutes matrix 124 Esthetic Restoratives Finishing Conventional GI Surface coat Wait 15 minutes Minimize trauma to surface Use blades Slow speed 125 Esthetic Restoratives Finishing RMGI Surface coat Immediate finishing Normal armamentarium Fine diamond Polishing discs Gentle technique 126 Esthetic Restoratives Surface Protection Protect setting cement Early moisture contamination Desiccation later Unfilled resins Essential Conventional Optional RMGI More resistant to water loss Fills irregularities Color stability Decreased F release Summitt, Fund Oper Dent 2001 127  Esthetic Restoratives RMGI Liners Posterior composite “Open-sandwich” technique Dentinal gingival margins Reduced leakage Reduced gap formation Examples Fuji II LC (GC) Vitremer (3M ESPE) 128 Applications Type 1: Luting cements Type 2: Restorative cements Esthetic restoratives Reinforced restoratives Condensable Metal-modified Type 3: Liners/sealants 129 Reinforced Restoratives (Type 2) Condensable Metal-modified 130 Condensable (Type 2) Conventional GI Simplified handling Indications Provisionalization Pediatric restorations Atraumatic Restorative Treatment Field dentistry Hand instrumentation Examples Fuji IX (GC) Ketac-Molar (3M ESPE) 131 Metal-Modified Glass Ionomers (Type 2) Conventional GI Silver fused with powder e.g., Ketac-Silver (3M ESPE) Amalgam alloy mixed with powder e.g., Miracle-Mix (GC) Improved handling Improved radiopacity Fluoride release Similar or slightly less than conventional Improved wear resistance 132 Metal-Modified Glass Ionomers (Type 2) Indications Non-stress bearing areas Core build-ups Low strength Minimize size Block-out Caries control Provisionals Atraumatic Restorative Treatment 133 Glass ionomer Cement ž Type II: Restorative cements ž There are two sub-divisions of Type II cements, depending on the importance of appearance — For anterior repairs where appearance matters, Type II (i): ○ Use high powder:liquid ratio (at least 3:1, and up to 6.8:1) ○ Have a good color match and translucency ○ Need protection from moisture for at least 24 hours with varnish, petroleum jelly or bonding system ○ Are usually radio-opaque 134 Glass ionomer Cement ž Type II: Restorative cements ž There are two sub-divisions of Type II cements, depending on the importance of appearance — For use where appearance is not important (posterior restoration or repairs), Type II (ii): ○ Also use high powder:liquid ratio (3:1 to 4:1) ○ Fast set and early resistance to water uptake ○ Radio-opaque 135 Applications Type 1: Luting cements Type 2: Restorative cements Esthetic restoratives Reinforced restoratives Condensable Metal-modified Type 3: Liners, bases/sealants 136 Liners (Type 3) Conventional Examples Ketac-Bond (3M ESPE) Lining Cement (GC) RMGI Examples Vitrebond (3M ESPE) Fuji Lining LC (GC) 137 Glass ionomer Cement ž Type III: Lining or base cements ž Low powder:liquid ratio for liners (1.5:1) to allow good adaptation to the cavity walls. ž Higher powder:liquid ratio for bases (3:1 to 6.8:1), where the base acts as a dentine substitute in the “open sandwich” technique in association with a composite resin. ž Radio-opaque. 138 Sealants (Type 3) Glass-ionomer “pre-cooperative” children Partially-erupted permanent molars Examples Riva Protect (SDI) Fuji Triage (GC) Resin-based sealants Higher retention Similar efficacy Proper isolation necessary 139 Pulpal Response Favorable Large molecules Limited tubule ingress Buffering of dentinal fluid Relatively weak acid Initial high acidity Chemical adhesion Minimizes microleakage Antimicrobial activity 140 COMPOMER 141 Compomers Composite and Glass-ionomer Polyacid-modified composite resin Matrix Dimethacrylate monomer Carboxylic groups Filler Ion-leachable glass H C=CH 2 CH=H2C No water COO-H C-H C-H C-H C 2 2 2 2 CH2-CH2-CH2-CH2-OOC C C Matrix Example HOOC COOH 142 Compomer ž Composition — Non-reactive inorganic filler particles — Reactive silicate glass particles — Sodium fluoride — Polyacid-modified monomer — Photo activator ž Polymerization reaction ž Absorb water form environment to allow acid-base reaction 143 Compomer ž Etch and dentin bonding because not self-adhesive ž No water in material ž Bond to surface like hybrid ionomer ž Low stress bearing area — Class III — Class V ž Color stability may be problem caused by water sorption and staining by food 144 Compomer ž One study in children (primary teeth) showed that it performed as well as composite resin sealants and Class I and II restorations ž Can be used for bonding orthodontic bands and brackets ž Adhesion to metal, fast curing and fluoride release 145 Compomer Setting reaction Free-radical polymerization reaction Similar to resin composites Resin-based adhesives No chemical bond to tooth structure Low levels of fluoride release Delayed acid-base reaction Later from tubules, absorption 146 Compomer ž Light-activated materials that integrates: — Fluoride releasing capability (GIC) — Durability of composite resin (CR) ž Performs better than RMGIC ž Inferior to hybrid composites ž One paste system ADVANTAGES Easy to place and polish Some fluoride release More esthetic than glass ionomer Better mechanical properties than glass ionomer Glass Ionomers RMGI Compomers Composites 148  Disadvantages Inferior mechanical properties compared to composite Less fluoride release than glass ionomer minimal recharge No chemical bond to tooth structure Glass Ionomers RMGI Compomers Composites el-Kalla, Oper Dent 1999 149 Indications Esthetics Areas of lower stress Class III, V Pediatric Conservative Class I and II 150 Contraindications Stress-bearing areas Permanent Class I or II Increased wear Loss of marginal integrity Poor isolation 151 Properties Property GI RMGI Compomer Composite Flexural Strength (MPa) 15-25 35-70 60-94 85-97 Compressive Strength (MPa) 170-200 180-210 190-250 230-270 Diametral Tensile Strength (MPa) 22-25 35-40 45-47 40-60 Fluoride Release High High Moderate Minimal- None Fluoride Recharge High High Moderate Minimal- None Glass Ionomers RMGI Compomers Composites Strength Polishability Fluoride Release 152 RESIN CEMENT 153 Resin Cement ž Composition similar to flowable composites with a lower filler content ž Light activated ž Chemically activated ž Dual activated 154 Resin cement ž Total etch Rely X ARC,Variolink II ,Calibra ,C&B ž Self-etch Panavia F ž Self-Adhesive Rely X Unicem 155 Resin Cement ž Use of adhesive — Total etch or self etch ž No adhesive — Self-etching primer in the resin cement — Reduction on post-operative sensitivity — Lower bond strength — Bond to enamel 156 Resin Cement ž Matrix – BIS-GMA, Urethane dimethacrylate ž Filler - 30%-80% submicron particles ž Coupling agent- Silane dimethacrylate 157 Resin Cements Self-etch Conventional Resin Cement Total etch Self- Adhesive 158 Resin Cements Total-etch E+P+B Self-Cure Dual-Cure Light Cured Chemical-activated Chemical and LC Veneer cements 159 Resin Cements Self-etch EP+B/EPB Self etch primers Acidic monomer 160 Self-adhesive Resin Cement ž Liquid-powder, paste-paste ž Paste-paste — Conventional monomer-paste 1 — Acid leachable filler-paste 1 — Acid functional monomers- paste 2 — Inert fillers – paste 2 — Initiators between 2 components 161 Self-adhesive Resin Cement ž No hybrid layer ž Show lower bond strength than non- self-adhesive ž Acidic monomer does not etch enamel ž Need to use phosphoric acid on enamel 162 Resin cement ž High adhesive quality (18-20MPa) ž ⇧ Retention ž High hardness ž Low solubility ž All metal, ceramic,composite (indirect) ž Occasional post-operative sensitivity 163 Resin cement ž Bond strength > Zinc phosphate (10 times) ž ↑ Retention ž Reinforced ceramic - based Crown ž Adhesive system (micromechanical bond-tooth) (chemical bond-porcelain,metal) ž Low solubility ž ↓ Leakage 164 Pre-treatment procedure 165 Polymerization ž Light-cured — Ceramic, porcelain, resin composite veneers or other light transmitting restorations (1.5 mm thick) ž Self cure/auto cure — Resin-bonded FPD, thick ceramic (2.5 mm thick), composite resin restorations, cast restorations ž Dual cure — Thin to moderately thick (1.5 to 2.5 mm thick) ceramic, porcelain and composite resin restorations where light transmission may be limited 166 Advantages of Resin Cements ž Excellent mechanical properties ž High bond strength with pre-Tx step ž High esthetics/translucency ž Suitable for ceramic, porcelain, composite resin, metal 167 Resin Cement Advantages v High compressive strength v Low solubility Disadvantages ž Effect on pulp ž Film thickness 168 Dental Luting Cement (Permanent) ž Zinc phosphate ž Polycarboxylate ž Glass ionomer ž RMGI cement ž Resin cement 169 Liners and Bases ž Zinc phosphate ž Polycarboxylate ž Glass ionomer ž RMGI cement ž Calcium Hydroxide 170  ZINC PHOSPHATE Advantages Disadvantages 1.Long clinical history 1.initial pulpal irritation 2.low film thickness 2.mechanical bond only 3.inexpensive 3.technique-sensitive mixing 4.high rigidity 4.relatively high solubility ZINC OXIDE EUGENOL Advantages Disadvantages Summary 1.A wide variety of uses 1.low strength 2.sedative to pulp 2.high solubility 3.easily manipulated 3.unable to be used under composite restorations and indirect restorations cemented with resin or hybrid GIC ZINC POLYCARBOXYLATE Advantages Disadvantages 1.bond to tooth structures 1.higher solubility 2.nonirritating to pulp 2.lower strength 3.inexpensive 3.shorter working time 171 Cement Ranking in Decreasing Order ž Compressive strength — Resin, GIC, ZP, PC, ZOE ž Solubility — Resin, GIC, Zinc Silicophosphate, ZP, ZOE- EBA, PC, ZOE 172 USES OF CEMENTS CEMENT Low strength base/liner CaOH, GIC, ZOE High strength base, Reinforced ZOE, ZP build-up ZPC,GIC Permanent cementation ZP, ZPC, GIC, Hybrid GIC, RC Cast crowns, ZP, ZPC, GIC, Hybrid inlays/onlays, bridges GIC, RC Porcelain, ceramic or RMGIC, RC and self- composite veneers, adhesive RC inlays, onlays and metal free crowns 173 USES OF CEMENTS CEMENT Endodontic posts GIC, RMGIC, RC, Self- adhesive RC Orthodontic bands Fluoride-added ZP, GIC Orthodontic brackets RC Provisional cements ZOE, No eugenol cements Provisional restorations Reinforce ZOE, ZPC, ZP Surgical dressing Eugenol and non-eugenol surgical dressing 174 Property GIC Hybrid Resin ZnPO ZnPC ZOE Ionomer Mechanical Mod* Mod High Low Low Low Solubility Mod Low Very low High High High Film thickness Low Low Low Low Low, Low, medium medium Postoperative High Low Low High Low Low sensitivity Fluoride High High None None None None Adhesion Good Good High None Moderate None Esthetics Good Good Good None None None Manipulation Moderately Easy Difficult Difficult Moderately Easy Easy easy * Moderate 175 References ž McCabe JF, Walls AWG (2008). Applied Dental Materials. 9th Edition Blackwell Publishing Ltd, Oxford ž Anusavice KJ Editor (2013) Phillip’s Science of Dental Materials. 12th Edition, Saunders, St Louis ž Shen C, Editor (2013) Phillip’s Science of Dental Materials. 13th Edition, Saunders, St Louis 176 END OF PART II 177