Dental CementsDental Cements

Libyan International Medical UniversityLibyan International Medical University

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What are uses of dental cementsWhat are uses of dental cements

1.1. Pulpal protectionPulpal protection

a. linera. liner

b. baseb. base

2. Luting cementation2. Luting cementation

3. Restorations3. Restorations

4. Surgical dressing4. Surgical dressing

5. Root canal sealer5. Root canal sealer

No cement is ideal for every clinical situation

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LinersLiners:: materials that are placed as thin coatings, materials that are placed as thin coatings, and their main function is to provide a barrier and their main function is to provide a barrier against chemical irritation. They against chemical irritation. They do not do not function function as thermal insulators. Selected primarily for as thermal insulators. Selected primarily for pulpal medication.pulpal medication.

BaseBase:: cement base (1 to 2 mm) function as cement base (1 to 2 mm) function as barriers against chemical irritation, provide barriers against chemical irritation, provide thermal insulation, and resist forces applied thermal insulation, and resist forces applied during condensation of the restorative material.during condensation of the restorative material.

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Properties of dental cementsProperties of dental cements

Strength…….resin Vs ZOEStrength…….resin Vs ZOE

Solubility……………microleakageSolubility……………microleakage

Viscosity……….film thicknessViscosity……….film thickness

BiocompatibilityBiocompatibility

RetentionRetention

Esthetics Esthetics

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Requirements of dental cementsRequirements of dental cements

1.1. Non-toxic, non irritant to the pulp and Non-toxic, non irritant to the pulp and other tissuesother tissues

2.2. Insoluble in saliva and in liquids taken Insoluble in saliva and in liquids taken into the mouthinto the mouth

3.3. Adhesion between the cement and tooth Adhesion between the cement and tooth tissue and between the cement and tissue and between the cement and restorationrestoration

4.4. Antibacterial effectAntibacterial effect

5.5. Relief the pain of the pulp…..Relief the pain of the pulp…..sedativesedative

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6. 6. When used for cementation or lutingWhen used for cementation or luting, they should , they should have: sufficient low viscosity to give a low film have: sufficient low viscosity to give a low film thickness, adequate working time, optical properties for thickness, adequate working time, optical properties for cementation of translucent restoration.cementation of translucent restoration.

7. 7. When used for cavity bases and liners:When used for cavity bases and liners: protect the protect the pulp from effects of other restorative materials, thermal pulp from effects of other restorative materials, thermal insulation under large metallic restorations, chemical insulation under large metallic restorations, chemical protection, electrical barrier to galvanism, rapid protection, electrical barrier to galvanism, rapid strength to permit packing of a filling materials and strength to permit packing of a filling materials and high modulus of elasticity high modulus of elasticity to prevent to prevent fracture due to fracture due to masticatory forces.masticatory forces.

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8. 8. When used as filling materials:When used as filling materials:

Ideally there should be bonding between filling Ideally there should be bonding between filling and enamel and dentin and marginal leakage and enamel and dentin and marginal leakage should not occur.should not occur.

Not dissolve in saliva or in fluids, low water Not dissolve in saliva or in fluids, low water absorption.absorption.

Mechanical properties should be adequate to Mechanical properties should be adequate to withstand force of mastication.withstand force of mastication.

Good esthetic and minimal dimensional changes. Good esthetic and minimal dimensional changes. Coefficient of thermal expansion should be Coefficient of thermal expansion should be similar to that of tooth.similar to that of tooth.

04/22/23 8Classification according to bonding mechanism

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Zinc phosphate cementZinc phosphate cement

• Zinc phosphate is the oldest cement, it serves Zinc phosphate is the oldest cement, it serves as standard for new types.as standard for new types.

• Powder: ZnO 90%, MgO, SiOPowder: ZnO 90%, MgO, SiO22, pigments, pigments

• Small particle size….fast setting.Small particle size….fast setting.

• Liquid: Phosphoric acid 40%, aluminum and Liquid: Phosphoric acid 40%, aluminum and zinc salts or metal ( why?) and water is 33%zinc salts or metal ( why?) and water is 33%

Buffering agents

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ManipulationManipulation

• Zinc oxide + phosphoric acid Zinc oxide + phosphoric acid Zinc aluminophosphate + heat

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• Proper amount of powder should be Proper amount of powder should be incorporated into the liquid slowly on a cool incorporated into the liquid slowly on a cool slab….why?slab….why?

• Large amount of powder Temp. will Large amount of powder Temp. will increased and this speed-up the reaction.increased and this speed-up the reaction.

Particle size and P/L ratio Particle size and P/L ratio

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• RetentionRetention.. Mechanical retention which based on .. Mechanical retention which based on the flow of cement into the microscopic the flow of cement into the microscopic irregularities on the tooth and surface of the irregularities on the tooth and surface of the restoration.restoration.

• Biocompatibility…. Irritant to pulp? Depends on Biocompatibility…. Irritant to pulp? Depends on depth of cavitydepth of cavity

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AdvantagesAdvantages::Good compressive strength (if correctly pro-portioned)Good compressive strength (if correctly pro-portioned)

Good film thicknessGood film thickness

Reasonable working timeReasonable working time

Resistance to water dissolutionResistance to water dissolution

DisadvantagesDisadvantages::Low tensile Strength no antibacterial actionLow tensile Strength no antibacterial action

No chemical bonding brittle No chemical bonding brittle

Not resistant to acid dissolutionNot resistant to acid dissolution

• Pulpal irritation? Low PHPulpal irritation? Low PH

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Zinc phosphate cementZinc phosphate cementRecommendations:Recommendations:

Good cement for conventional crowns and posts with Good cement for conventional crowns and posts with retentive preparations.retentive preparations.

Working time can be extended for cementation of multiple Working time can be extended for cementation of multiple restorations by incremental mixing and cooled slab. restorations by incremental mixing and cooled slab.

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Zinc oxide eugenol cementZinc oxide eugenol cement

• Characterized by their sedative effect on the Characterized by their sedative effect on the pulp and neutral pH.pulp and neutral pH.

• Powder: zinc oxide 69% + zinc stearate +zinc Powder: zinc oxide 69% + zinc stearate +zinc acetate + rosinacetate + rosin

• Liquid: Eugenol 85% + olive oilLiquid: Eugenol 85% + olive oil

• Zinc oxide + eugenol zinc eugenolateZinc oxide + eugenol zinc eugenolate

• The reaction is The reaction is reversiblereversible if there is moisture. if there is moisture.

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ApplicationsApplications• Temporary cementation of cast restorations.Temporary cementation of cast restorations.• Temporary filling material of teeth.Temporary filling material of teeth.• Cavity liner in deep cavityCavity liner in deep cavity• Root canal sealerRoot canal sealer• Surgical dressingSurgical dressing

They are supplied in the form of powder andThey are supplied in the form of powder and

liquid or two paste-system or one ready madeliquid or two paste-system or one ready made

pastepaste

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• Classical soft cement.Classical soft cement.

• Attempts have been made to create a more Attempts have been made to create a more permanent cement by adding O-ethoxy-benzoic permanent cement by adding O-ethoxy-benzoic acid (EBA) and by reinforcing it with acid (EBA) and by reinforcing it with aluminium oxide and polymethylmethacrylate.aluminium oxide and polymethylmethacrylate.

• But still it can not be recommended as a But still it can not be recommended as a definitive lute for restorations.definitive lute for restorations.

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Zinc polycarboxylate cementsZinc polycarboxylate cements

• Was the first cement system that developed Was the first cement system that developed an adhesive bond to tooth structure.an adhesive bond to tooth structure.

• PowderPowder: mainly zinc oxide with some tin or : mainly zinc oxide with some tin or magnesium or aluminium oxide. Small magnesium or aluminium oxide. Small quantity of fluoride can be added to provide quantity of fluoride can be added to provide leachable leachable fluoride..

• Liquid:Liquid: 40% polyacrylic acid or an acrylic 40% polyacrylic acid or an acrylic acid copolymer with other organic acids.acid copolymer with other organic acids.

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Setting reactionSetting reaction• Zinc oxide + polyacrylic acid zinc polyacrylate + unreacted Zinc oxide + polyacrylic acid zinc polyacrylate + unreacted

ZnO powder (amorphous gel matrix)ZnO powder (amorphous gel matrix)

• During mixing, powder is rapidly incorporated into the During mixing, powder is rapidly incorporated into the liquid in large quantities and mixed for 30 to 60 s over liquid in large quantities and mixed for 30 to 60 s over small area of glass slab to prevent destruction of the small area of glass slab to prevent destruction of the formed gel.formed gel.

• Working time Working time approximately approximately 2.52.5 minmin as compared with as compared with 5 min5 min. for zinc phosphate.. for zinc phosphate.

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ApplicationsApplications

• Cementation of cast or PFM restorations Cementation of cast or PFM restorations orthodontic bands.orthodontic bands.

• Cavity liner or base.Cavity liner or base.

• Temporary filling material.Temporary filling material.

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RetentionRetention

• Chemically bond (Chemically bond (ionicionic bondbond) to enamel and ) to enamel and dentine.dentine.

• It bonds to enamel more than dentine It bonds to enamel more than dentine because of high content of calcium.because of high content of calcium.

• It does not bond to porcelain.It does not bond to porcelain.

• It bonds well to base of metal alloys and It bonds well to base of metal alloys and stainless steel (used in cementation of stainless steel (used in cementation of orthodontic band).orthodontic band).

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• Advantages:Advantages:

1. reasonable truck record1. reasonable truck record

2. good compressive st.2. good compressive st.

3. adequate working time???3. adequate working time???

4. bonds to enamel and dentine4. bonds to enamel and dentine

5. adequate resistance to water dissolution 5. adequate resistance to water dissolution (but less than zinc phosphate)(but less than zinc phosphate)

6. no adverse effect on pulp and less acidic 6. no adverse effect on pulp and less acidic than zinc phosphate cement.than zinc phosphate cement.

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• DisadvantagesDisadvantages::

1. low tensile st.1. low tensile st.

2. can deform under loading2. can deform under loading

3. can be difficult to obtain low film 3. can be difficult to obtain low film thickness.thickness.

4. not resistant to acid dissolution.4. not resistant to acid dissolution.

5. need for clean dry surfaces to utilize the 5. need for clean dry surfaces to utilize the adhesion potential.adhesion potential.

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RecommendationsRecommendations

• Traditionally used for vital or sensitive teeth.Traditionally used for vital or sensitive teeth.

• Occasionally useful to retain an unretentive Occasionally useful to retain an unretentive provisional crown and bridge.provisional crown and bridge.

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Resin cementsResin cements

• Basically its fluid composite, achieved by Basically its fluid composite, achieved by reduce amount of fillers.reduce amount of fillers.

AdvantagesAdvantages::

Good compressive and tensile strengths.Good compressive and tensile strengths.

High tensile strength than conventional cements.High tensile strength than conventional cements.

Resistance to water dissolution.Resistance to water dissolution.

Relatively resistant to acid dissolution.Relatively resistant to acid dissolution.

Can enhance strength of ceramic restoration.Can enhance strength of ceramic restoration.

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• Disadvantages:Disadvantages:

• Film thickness varies between materials.Film thickness varies between materials.

• Excess material extruded at margin may be Excess material extruded at margin may be difficult to remove especially proximally.difficult to remove especially proximally.

• Could be irritant to the pulp?? Could be irritant to the pulp??

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RecommendationsRecommendations

• Must be used with or incorporation an Must be used with or incorporation an effective dentine bonding agent.effective dentine bonding agent.

• Material of choice for porcelain veneers, Material of choice for porcelain veneers, ceramic onlays, inlays and crowns.ceramic onlays, inlays and crowns.

• May be used to improve retention where May be used to improve retention where preparation geometry sub-optimal, but preparation geometry sub-optimal, but clinical studies needed to determine long-clinical studies needed to determine long-term success.term success.

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Calcium hydroxide cementsCalcium hydroxide cements

• Pulp-capping material that facilitate the Pulp-capping material that facilitate the formation of reparative dentineformation of reparative dentine

• Used as direct or indirect pulp capping.Used as direct or indirect pulp capping.

• Protective linerProtective liner

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• Presented as:Presented as:

1- 1- calcium hydroxide suspensions:calcium hydroxide suspensions: applied to the base applied to the base of the cavity and dries out to give a layer of calcium of the cavity and dries out to give a layer of calcium hydroxide. Difficult to manipulate and form very weak hydroxide. Difficult to manipulate and form very weak lining. lining.

2- 2- chemical cured calcium hydroxide cementchemical cured calcium hydroxide cement::

Two paste system, most commonTwo paste system, most commonCalcium hydroxide + salicylate calcium disalicylateCalcium hydroxide + salicylate calcium disalicylate

Fillers such as barium sulphate provide radiopacity.Fillers such as barium sulphate provide radiopacity.

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3- 3- Light- cured calcium hydroxide cements:Light- cured calcium hydroxide cements:

Its recently available and easy of application.Its recently available and easy of application.Ca (OH)Ca (OH)22 + Bis-GMA + barium sulphate + light sensitive material + Bis-GMA + barium sulphate + light sensitive material

Properties:Properties:The pH (11-12). This degree of alkalinity stimulate The pH (11-12). This degree of alkalinity stimulate

odontoblast cells to produce reparative dentine.odontoblast cells to produce reparative dentine.

Easy manipulationEasy manipulation

Rapid hardening in thin layerRapid hardening in thin layer

Good sealing, high solubility, low compressive st. 5 MPa,Good sealing, high solubility, low compressive st. 5 MPa,

they have antibacterial effect.they have antibacterial effect.

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VarnishesVarnishes

• If amalgam or direct gold is to be used, the If amalgam or direct gold is to be used, the prepared cavity coated with a varnish.prepared cavity coated with a varnish.

• Cavity varnish is natural or synthetic resin Cavity varnish is natural or synthetic resin dissolve in a solvent such as ether.dissolve in a solvent such as ether.

• The solvent evaporate leaving a thin film on The solvent evaporate leaving a thin film on the cavity preparation.the cavity preparation.

• Main function to reduce microleakage that Main function to reduce microleakage that occur in conjunction with the amalgam occur in conjunction with the amalgam restorations.restorations.

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• Cavity varnish inhibits microleakage during Cavity varnish inhibits microleakage during the first few weeks until corrosion products the first few weeks until corrosion products form.form.

• A varnish is not used when the restoration A varnish is not used when the restoration is composite. Because it retard or prevent is composite. Because it retard or prevent the polymerization.the polymerization.

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Glass ionomer cementsGlass ionomer cements• GICs are widely (1970) used in the dental field GICs are widely (1970) used in the dental field

because of their adhesion, bio-compatibility because of their adhesion, bio-compatibility and anticariogenic properties. and anticariogenic properties.

• Presented asPresented as: powder and liquid, capsules to : powder and liquid, capsules to be mixed with mixer, powder to be mixed with be mixed with mixer, powder to be mixed with water.water.

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• Powder: mainly calcium aluminosilicate glass Powder: mainly calcium aluminosilicate glass with fluoride salts.with fluoride salts.

• Liquid: 50% aqueous solution of polyacrylic acidLiquid: 50% aqueous solution of polyacrylic acid

• GIC bond chemically GIC bond chemically to enamel and dentine to enamel and dentine during the setting process.during the setting process.

• Ionic interaction Ionic interaction with calcium and/or phosphate with calcium and/or phosphate ions from the surface of the enamel or dentine.ions from the surface of the enamel or dentine.

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ApplicationApplication

1. Cementation or luting for restorations1. Cementation or luting for restorations

2. Cavity base or liners material2. Cavity base or liners material

3. Orthodontic band cementation3. Orthodontic band cementation

4. Permanent restorations class III, V, especially 4. Permanent restorations class III, V, especially for erosion/abrasion lesions and deciduous for erosion/abrasion lesions and deciduous teethteeth

5. Pit and fissure sealant5. Pit and fissure sealant

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Setting reactionSetting reaction

• Acid base reaction between the ion Acid base reaction between the ion leachable glass and polyacrylic acid, it leachable glass and polyacrylic acid, it involves three stages:involves three stages:

1.1. Dissolution Dissolution

2.2. GelationGelation

3.3. HydrationHydration

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The structure of the set cementThe structure of the set cement

1

32

(1) alumino-silicate glass, (2) silicate gel, (3) cross-linked polyacid

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Un-reacted glass particles surrounded by silica gel held Un-reacted glass particles surrounded by silica gel held together by an amorphous matrix of hydrated calcium together by an amorphous matrix of hydrated calcium and aluminum polyacrylate salts.and aluminum polyacrylate salts.

• Types: Types:

I. Cementation of restorationI. Cementation of restoration

II. Restoration class III and V..low stress bearing areas.II. Restoration class III and V..low stress bearing areas.

III. Lining or base material, pit and fissure sealing.III. Lining or base material, pit and fissure sealing.

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• Working time about 2 minWorking time about 2 min

• GIC very sensitive to contact with water GIC very sensitive to contact with water during settingduring setting

• Initial set after 7 minInitial set after 7 min

• Cement margin should be coated with coating Cement margin should be coated with coating agent supplied with cement or Vaseline or agent supplied with cement or Vaseline or varnish!varnish!

• After 24 h, solubility in water is about 1%After 24 h, solubility in water is about 1%

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BondingBonding

• Ionic bondIonic bond

• Chelation of carboxyl groups of the Chelation of carboxyl groups of the polyacids with calcium in the apatite of polyacids with calcium in the apatite of enamel and dentine.enamel and dentine.

• To achieve long lasting bond, the prepared To achieve long lasting bond, the prepared surface must be clean and dry to remove a surface must be clean and dry to remove a smear layer.smear layer.

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AdvantagesAdvantages

• Adhesion to tooth structureAdhesion to tooth structure

• Long term fluoride releaseLong term fluoride release

• BiocompatibilityBiocompatibility

• High compressive stHigh compressive st

• Low solubility in oral fluidsLow solubility in oral fluids

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DisadvantagesDisadvantages

• Technique sensitiveTechnique sensitive

• Sensitive to water contamination and Sensitive to water contamination and dehydrationdehydration

• Short working time and long setting timeShort working time and long setting time

• Low abrasion resistanceLow abrasion resistance

• Brittleness (low tensile st)Brittleness (low tensile st)

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Metal reinforced GICMetal reinforced GIC1.1. Silver alloy admix, simple mix of silver alloy Silver alloy admix, simple mix of silver alloy

amalgam powder with GIC powder before amalgam powder with GIC powder before mixing with acid.mixing with acid.

The addition of metals to regular GIC increase The addition of metals to regular GIC increase abrasion resistance, compressive st., and reduce abrasion resistance, compressive st., and reduce the solubility in the oral fluids. However, it the solubility in the oral fluids. However, it reduce fluride release and the bond st.reduce fluride release and the bond st.

Used as posterior filling material for decidous teeth.Used as posterior filling material for decidous teeth.

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Hybrid Ionomer (resin modified)Hybrid Ionomer (resin modified)

• RMGIC, this material introduced to RMGIC, this material introduced to overcome the disadvantages of moisture overcome the disadvantages of moisture sensitivity, short working time and long sensitivity, short working time and long setting time of conventional GIC.setting time of conventional GIC.

• Addition of some polymerizable groups Addition of some polymerizable groups (resin) to the composition of GIC.(resin) to the composition of GIC.

• Could be light or chemical cure. Could be light or chemical cure.

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Dual cure GICDual cure GIC

• THIS means that the cement sets by 2 THIS means that the cement sets by 2 reactions: conventional acid-base reaction reactions: conventional acid-base reaction and light curing reaction of resin.and light curing reaction of resin.

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CompomerCompomer

• Combination of composite and Combination of composite and conventional fluoride release GIC.conventional fluoride release GIC.

• Has structure and physical properties and Has structure and physical properties and durability similar of composite and fluoride durability similar of composite and fluoride release of GIC, and it undergoes an acid-release of GIC, and it undergoes an acid-base reaction in the presence of saliva.base reaction in the presence of saliva.

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ApplicationsApplications

1.1. Restorations of deciduous teeth.Restorations of deciduous teeth.

2.2. Class V (cervical caries, root erosion)Class V (cervical caries, root erosion)

3.3. Class IIIClass III

4.4. Intermediate class I and IIIntermediate class I and II

5.5. Cementation of cast alloys and all ceramic Cementation of cast alloys and all ceramic restorationsrestorations

04/22/23 49Sandwich technique

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Thank you for attention