Dental Cements Libyan International Medical University

10/25/20152 What are uses of dental cements 1.Pulpal protection a. liner a. liner b. base b. base 2. Luting cementation 3. Restorations 4. Surgical dressing 5. Root canal sealer No cement is ideal for every clinical situation

10/25/20153 Liners: materials that are placed as thin coatings, and their main function is to provide a barrier against chemical irritation. They do not function as thermal insulators. Selected primarily for pulpal medication. Base: cement base (1 to 2 mm) function as barriers against chemical irritation, provide thermal insulation, and resist forces applied during condensation of the restorative material.

10/25/20154 Properties of dental cements Strength…….resin Vs ZOE Solubility……………microleakage Viscosity……….film thickness BiocompatibilityRetentionEsthetics

10/25/20155 Requirements of dental cements 1.Non-toxic, non irritant to the pulp and other tissues 2.Insoluble in saliva and in liquids taken into the mouth 3.Adhesion between the cement and tooth tissue and between the cement and restoration 4.Antibacterial effect 5.Relief the pain of the pulp…..sedative

10/25/ When used for cementation or luting, they should have: sufficient low viscosity to give a low film thickness, adequate working time, optical properties for cementation of translucent restoration. 7. When used for cavity bases and liners: protect the pulp from effects of other restorative materials, thermal insulation under large metallic restorations, chemical protection, electrical barrier to galvanism, rapid strength to permit packing of a filling materials and high modulus of elasticity to prevent fracture due to masticatory forces.

10/25/ When used as filling materials: Ideally there should be bonding between filling and enamel and dentin and marginal leakage should not occur. Not dissolve in saliva or in fluids, low water absorption. Mechanical properties should be adequate to withstand force of mastication. Good esthetic and minimal dimensional changes. Coefficient of thermal expansion should be similar to that of tooth.

10/25/20158 Classification according to bonding mechanism

10/25/20159 Zinc phosphate cement Zinc phosphate is the oldest cement, it serves as standard for new types.Zinc phosphate is the oldest cement, it serves as standard for new types. Powder: ZnO 90%, MgO, SiO 2, pigmentsPowder: ZnO 90%, MgO, SiO 2, pigments Small particle size….fast setting.Small particle size….fast setting. Liquid: Phosphoric acid 40%, aluminum and zinc salts or metal ( why?) and water is 33%Liquid: Phosphoric acid 40%, aluminum and zinc salts or metal ( why?) and water is 33% Buffering agents

10/25/ Manipulation Zinc oxide + phosphoric acidZinc oxide + phosphoric acid Zinc aluminophosphate + heat

10/25/ Proper amount of powder should be incorporated into the liquid slowly on a cool slab….why?Proper amount of powder should be incorporated into the liquid slowly on a cool slab….why? Large amount of powder Temp. will increased and this speed-up the reaction.Large amount of powder Temp. will increased and this speed-up the reaction. Particle size and P/L ratio Particle size and P/L ratio

10/25/ Retention.. Mechanical retention which based on the flow of cement into the microscopic irregularities on the tooth and surface of the restoration.Retention.. Mechanical retention which based on the flow of cement into the microscopic irregularities on the tooth and surface of the restoration. Biocompatibility…. Irritant to pulp? Depends on depth of cavityBiocompatibility…. Irritant to pulp? Depends on depth of cavity

10/25/ Advantages: Good compressive strength (if correctly pro-portioned) Good film thickness Reasonable working time Resistance to water dissolution Disadvantages: Low tensile Strength no antibacterial action No chemical bonding brittle Not resistant to acid dissolution Pulpal irritation? Low PHPulpal irritation? Low PH

10/25/ Zinc phosphate cement Recommendations: Good cement for conventional crowns and posts with retentive preparations. Working time can be extended for cementation of multiple restorations by incremental mixing and cooled slab.

10/25/ Zinc oxide eugenol cement Characterized by their sedative effect on the pulp and neutral pH.Characterized by their sedative effect on the pulp and neutral pH. Powder: zinc oxide 69% + zinc stearate +zinc acetate + rosinPowder: zinc oxide 69% + zinc stearate +zinc acetate + rosin Liquid: Eugenol 85% + olive oilLiquid: Eugenol 85% + olive oil Zinc oxide + eugenol zinc eugenolateZinc oxide + eugenol zinc eugenolate The reaction is reversible if there is moisture.The reaction is reversible if there is moisture.

10/25/ Applications 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 and liquid or two paste-system or one ready made paste

10/25/ Classical soft cement.Classical soft cement. Attempts have been made to create a more permanent cement by adding O-ethoxy-benzoic acid (EBA) and by reinforcing it with aluminium oxide and polymethylmethacrylate.Attempts have been made to create a more permanent cement by adding O-ethoxy-benzoic acid (EBA) and by reinforcing it with aluminium oxide and polymethylmethacrylate. But still it can not be recommended as a definitive lute for restorations.But still it can not be recommended as a definitive lute for restorations.

10/25/ Zinc polycarboxylate cements Was the first cement system that developed an adhesive bond to tooth structure.Was the first cement system that developed an adhesive bond to tooth structure. Powder: mainly zinc oxide with some tin or magnesium or aluminium oxide. Small quantity of fluoride can be added to provide leachable.Powder: mainly zinc oxide with some tin or magnesium or aluminium oxide. Small quantity of fluoride can be added to provide leachable fluoride. Liquid: 40% polyacrylic acid or an acrylic acid copolymer with other organic acids.Liquid: 40% polyacrylic acid or an acrylic acid copolymer with other organic acids.

10/25/ Setting reaction Zinc oxide + polyacrylic acid zinc polyacrylate + unreacted ZnO powder (amorphous gel matrix)Zinc oxide + polyacrylic acid zinc polyacrylate + unreacted ZnO powder (amorphous gel matrix) During mixing, powder is rapidly incorporated into the liquid in large quantities and mixed for 30 to 60 s over small area of glass slab to prevent destruction of the formed gel.During mixing, powder is rapidly incorporated into the liquid in large quantities and mixed for 30 to 60 s over small area of glass slab to prevent destruction of the formed gel. Working time approximately 2.5 min as compared with 5 min. for zinc phosphate.Working time approximately 2.5 min as compared with 5 min. for zinc phosphate.

10/25/ Applications Cementation of cast or PFM restorations orthodontic bands.Cementation of cast or PFM restorations orthodontic bands. Cavity liner or base.Cavity liner or base. Temporary filling material.Temporary filling material.

10/25/ Retention Chemically bond (ionic bond) to enamel and dentine.Chemically bond (ionic bond) to enamel and dentine. It bonds to enamel more than dentine because of high content of calcium.It bonds to enamel more than dentine 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 stainless steel (used in cementation of orthodontic band).It bonds well to base of metal alloys and stainless steel (used in cementation of orthodontic band).

10/25/ Advantages:Advantages: 1. reasonable truck record 1. reasonable truck record 2. good compressive st. 2. good compressive st. 3. adequate working time??? 3. adequate working time??? 4. bonds to enamel and dentine 4. bonds to enamel and dentine 5. adequate resistance to water dissolution (but less than zinc phosphate) 5. adequate resistance to water dissolution (but less than zinc phosphate) 6. no adverse effect on pulp and less acidic than zinc phosphate cement. 6. no adverse effect on pulp and less acidic than zinc phosphate cement.

10/25/ Disadvantages:Disadvantages: 1. low tensile st. 1. low tensile st. 2. can deform under loading 2. can deform under loading 3. can be difficult to obtain low film thickness. 3. can be difficult to obtain low film thickness. 4. not resistant to acid dissolution. 4. not resistant to acid dissolution. 5. need for clean dry surfaces to utilize the adhesion potential. 5. need for clean dry surfaces to utilize the adhesion potential.

10/25/ Recommendations Traditionally used for vital or sensitive teeth.Traditionally used for vital or sensitive teeth. Occasionally useful to retain an unretentive provisional crown and bridge.Occasionally useful to retain an unretentive provisional crown and bridge.

10/25/ Resin cements Basically its fluid composite, achieved by reduce amount of fillers.Basically its fluid composite, achieved by reduce amount of fillers. Advantages: Good compressive and tensile strengths. High tensile strength than conventional cements. Resistance to water dissolution. Relatively resistant to acid dissolution. Can enhance strength of ceramic restoration.

10/25/ Disadvantages:Disadvantages: Film thickness varies between materials.Film thickness varies between materials. Excess material extruded at margin may be difficult to remove especially proximally.Excess material extruded at margin may be difficult to remove especially proximally. Could be irritant to the pulp??Could be irritant to the pulp??

10/25/ Recommendations Must be used with or incorporation an effective dentine bonding agent.Must be used with or incorporation an effective dentine bonding agent. Material of choice for porcelain veneers, ceramic onlays, inlays and crowns.Material of choice for porcelain veneers, ceramic onlays, inlays and crowns. May be used to improve retention where preparation geometry sub-optimal, but clinical studies needed to determine long- term success.May be used to improve retention where preparation geometry sub-optimal, but clinical studies needed to determine long- term success.

10/25/ Calcium hydroxide cements Pulp-capping material that facilitate the formation of reparative dentinePulp-capping material that facilitate the formation of reparative dentine Used as direct or indirect pulp capping.Used as direct or indirect pulp capping. Protective linerProtective liner

10/25/ Presented as:Presented as: 1- calcium hydroxide suspensions: applied to the base of the cavity and dries out to give a layer of calcium hydroxide. Difficult to manipulate and form very weak lining. 2- chemical cured calcium hydroxide cement: Two paste system, most common Calcium hydroxide + salicylate calcium disalicylate Fillers such as barium sulphate provide radiopacity.

10/25/ Light- cured calcium hydroxide cements: Its recently available and easy of application. Ca (OH) 2 + Bis-GMA + barium sulphate + light sensitive material Properties: The pH (11-12). This degree of alkalinity stimulate odontoblast cells to produce reparative dentine. Easy manipulation Rapid hardening in thin layer Good sealing, high solubility, low compressive st. 5 MPa, they have antibacterial effect.

10/25/ Varnishes If amalgam or direct gold is to be used, the prepared cavity coated with a varnish.If amalgam or direct gold is to be used, the prepared cavity coated with a varnish. Cavity varnish is natural or synthetic resin dissolve in a solvent such as ether.Cavity varnish is natural or synthetic resin dissolve in a solvent such as ether. The solvent evaporate leaving a thin film on the cavity preparation.The solvent evaporate leaving a thin film on the cavity preparation. Main function to reduce microleakage that occur in conjunction with the amalgam restorations.Main function to reduce microleakage that occur in conjunction with the amalgam restorations.

10/25/ Cavity varnish inhibits microleakage during the first few weeks until corrosion products form.Cavity varnish inhibits microleakage during the first few weeks until corrosion products form. A varnish is not used when the restoration is composite. Because it retard or prevent the polymerization.A varnish is not used when the restoration is composite. Because it retard or prevent the polymerization.

10/25/ Glass ionomer cements GICs are widely (1970) used in the dental field because of their adhesion, bio-compatibility and anticariogenic properties.GICs are widely (1970) used in the dental field because of their adhesion, bio-compatibility and anticariogenic properties. Presented as: powder and liquid, capsules to be mixed with mixer, powder to be mixed with water.Presented as: powder and liquid, capsules to be mixed with mixer, powder to be mixed with water.

10/25/ Powder: mainly calcium aluminosilicate glass with fluoride salts.Powder: mainly calcium aluminosilicate glass with fluoride salts. Liquid: 50% aqueous solution of polyacrylic acidLiquid: 50% aqueous solution of polyacrylic acid GIC bond chemically to enamel and dentine during the setting process.GIC bond chemically to enamel and dentine during the setting process. Ionic interaction with calcium and/or phosphate ions from the surface of the enamel or dentine.Ionic interaction with calcium and/or phosphate ions from the surface of the enamel or dentine.

10/25/ Application 1. Cementation or luting for restorations 2. Cavity base or liners material 3. Orthodontic band cementation 4. Permanent restorations class III, V, especially for erosion/abrasion lesions and deciduous teeth 5. Pit and fissure sealant

10/25/ Setting reaction Acid base reaction between the ion leachable glass and polyacrylic acid, it involves three stages:Acid base reaction between the ion leachable glass and polyacrylic acid, it involves three stages: 1.Dissolution 2.Gelation 3.Hydration

10/25/ The structure of the set cement (1) alumino-silicate glass, (2) silicate gel, (3) cross-linked polyacid

10/25/ Un-reacted glass particles surrounded by silica gel held together by an amorphous matrix of hydrated calcium and aluminum polyacrylate salts. Types:Types: I. Cementation of restoration I. 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.

10/25/ Working time about 2 minWorking time about 2 min GIC very sensitive to contact with water during settingGIC very sensitive to contact with water during setting Initial set after 7 minInitial set after 7 min Cement margin should be coated with coating agent supplied with cement or Vaseline or varnish!Cement margin should be coated with coating agent supplied with cement or Vaseline or varnish! After 24 h, solubility in water is about 1%After 24 h, solubility in water is about 1%

10/25/ Bonding Ionic bondIonic bond Chelation of carboxyl groups of the polyacids with calcium in the apatite of enamel and dentine.Chelation of carboxyl groups of the polyacids with calcium in the apatite of enamel and dentine. To achieve long lasting bond, the prepared surface must be clean and dry to remove a smear layer.To achieve long lasting bond, the prepared surface must be clean and dry to remove a smear layer.

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10/25/ Advantages 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

10/25/ Disadvantages Technique sensitiveTechnique sensitive Sensitive to water contamination and dehydrationSensitive to water contamination and dehydration 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)

10/25/ Metal reinforced GIC 1.Silver alloy admix, simple mix of silver alloy amalgam powder with GIC powder before mixing with acid. The addition of metals to regular GIC increase abrasion resistance, compressive st., and reduce the solubility in the oral fluids. However, it reduce fluride release and the bond st. Used as posterior filling material for decidous teeth.

10/25/ Hybrid Ionomer (resin modified) RMGIC, this material introduced to overcome the disadvantages of moisture sensitivity, short working time and long setting time of conventional GIC.RMGIC, this material introduced to overcome the disadvantages of moisture sensitivity, short working time and long setting time of conventional GIC. Addition of some polymerizable groups (resin) to the composition of GIC.Addition of some polymerizable groups (resin) to the composition of GIC. Could be light or chemical cure.Could be light or chemical cure.

10/25/ Dual cure GIC THIS means that the cement sets by 2 reactions: conventional acid-base reaction and light curing reaction of resin.THIS means that the cement sets by 2 reactions: conventional acid-base reaction and light curing reaction of resin.

10/25/ Compomer Combination of composite and conventional fluoride release GIC.Combination of composite and conventional fluoride release GIC. Has structure and physical properties and durability similar of composite and fluoride release of GIC, and it undergoes an acid- base reaction in the presence of saliva.Has structure and physical properties and durability similar of composite and fluoride release of GIC, and it undergoes an acid- base reaction in the presence of saliva.

10/25/ Applications 1.Restorations of deciduous teeth. 2.Class V (cervical caries, root erosion) 3.Class III 4.Intermediate class I and II 5.Cementation of cast alloys and all ceramic restorations

10/25/ Sandwich technique

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10/25/ Thank you for attention