1)Dental Cements in Restorative Dentistry

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Questions and Answers

Which cement can be used for pulp capping under composite restorations?

Type III glass ionomer cement

Resin cement

Zinc polycarboxylate cement (correct)

Zinc phosphate cement

What is the primary purpose of using zinc phosphate cement?

Cavity liner

Pulp protection

Temporary luting (correct)

Root canal sealing

Which cement has been in use since 1878 and is considered one of the oldest cements?

Resin cement

Zinc polycarboxylate cement (correct)

Zinc oxide eugenol cement

Glass ionomer cement

For which restorative material can reinforced ZOE be used as a base?

Amalgam restorations Signup and view all the answers

Which cement is suitable for indirect pulp capping during a dental procedure?

Zinc polycarboxylate cement Signup and view all the answers

What is the main property of zinc phosphate cement specified in the text?

Film thickness < 25 microns Signup and view all the answers

What is the film thickness of Type II Zinc Phosphate cement?

25-40 microns Signup and view all the answers

What is the setting reaction of Zinc Phosphate cement?

Exothermic acid-base reaction Signup and view all the answers

What is the tensile strength of Type II Zinc Phosphate cement?

5.5 Mpa Signup and view all the answers

How long does it take for Type II Zinc Phosphate cement to retain 75% of its ultimate strength?

1 hour Signup and view all the answers

What is a disadvantage of Zinc Polycarboxylate Cement?

Solubility in water Signup and view all the answers

How does Zinc Polycarboxylate Cement set?

Acid-base reaction with calcium Signup and view all the answers

What is the setting reaction of zinc oxide eugenol cement?

Zn(OH)2 + 2HE -> ZnE2 + 2H2O Signup and view all the answers

What is one of the disadvantages of zinc oxide eugenol cement in terms of clinical use?

Low compressive strength Signup and view all the answers

Which of the following statements is true about the biocompatibility of zinc oxide eugenol cement?

Sedative effect on the pulp Signup and view all the answers

When is zinc oxide eugenol cement commonly used in clinical practice?

Temporary restorations Signup and view all the answers

What is a notable advantage of zinc oxide eugenol cement over zinc phosphate cement?

Better marginal seal Signup and view all the answers

Why is zinc oxide eugenol cement not recommended as a base material for unfilled and filled resins?

It interferes with the polymerization process of resins Signup and view all the answers

What is the main component of the powder in the EBA cement?

Zinc oxide Signup and view all the answers

What is the benefit of adding fused quartz, alumina and dicalcium phosphate to the EBA cement?

Increases compressive and tensile strength Signup and view all the answers

What is the main component of the liquid in the EBA cement?

Ortho-ethoxybenzoic acid (EBA) Signup and view all the answers

What is the main purpose of the polymer reinforced zinc oxide powder?

Increases strength Signup and view all the answers

What is the main role of the acetic acid in the polymer reinforced zinc oxide cement?

Accelerates the setting reaction Signup and view all the answers

What is the main disadvantage of the EBA cement?

Plastic deformation Signup and view all the answers

What is the primary setting reaction of zinc polycarboxylate cement?

Acid-base reaction Signup and view all the answers

Which factor increases the working time of zinc polycarboxylate cement?

Decreasing the temperature Signup and view all the answers

What is the typical powder/liquid ratio recommended for mixing zinc polycarboxylate cement?

1.5/1 Signup and view all the answers

Which of the following statements about the bond of zinc polycarboxylate cement to tooth structure is correct?

It bonds through a chemical reaction with calcium in tooth structure Signup and view all the answers

Which property of zinc polycarboxylate cement is accurately described in the text?

Low tensile strength (2.4-4.4 MPa) Signup and view all the answers

What is the initial pH of the liquid component of zinc polycarboxylate cement?

1.7 Signup and view all the answers

Study Notes

Properties of Dental Cements

Resistance to solubility in the oral cavity
Bonding
Compressive and tensile strength
Biocompatibility
Working time
Protects pulp from mechanical and electrical stimuli

Classification of Dental Cements

Permanent luting cements
Temporary luting cements
Permanent restorative materials
Temporary restorative materials
Bases: under amalgam/composite/gold
Pulp capping: indirect pulp capping/direct pulp capping
Cavity liners: under amalgam/composite

Zinc Phosphate Cement

First introduced in 1878 and still used today
Type I: used for cementation; film thickness < 25 microns
Type II: used as a base and for luting; film thickness 25-40 microns
Powder composition: 90.2% ZnO, 8.2% MgO, 1.4% SiO2, 0.1% Bi2O3, 0.1% BaO, Ba2SO4, CaO
Acid-base reaction rate
Setting reaction: zinc oxide + phosphoric acid
Manipulation: glass slab, dry, lower temperature for longer working time
Mechanical Properties:
- Compressive strength: 104 Mpa
- Tensile strength: 5.5 Mpa
- Modulus of Elasticity: 13.7 gigapascals
- Retention of cement is by mechanical interlocking
Biocompatibility: phosphoric acid, liquid pH 2.0, acidity, irritation
Clinical uses: base, temporary restoration, cementation
Advantages: long record of clinical acceptability, high compressive strength, thin film thickness
Disadvantages: low initial pH, lack of adhesion to tooth structure, lack of anticariogenic effect, soluble in water

Zinc Polycarboxylate Cement

Introduced in the 1960s
Chelation reaction
Sets by an acid-base reaction between powder and liquid
Clinical use: base, temporary restorations, cement crowns, stainless steel crown
Advantages: adhesion, rapid rise in pH upon cementation
Disadvantages: lack of penetration into dentinal tubules, short working time, not resistant to plastic deformation

Zinc Oxide Eugenol Cement

Introduced in the 1890s
Less soluble in oral fluids
Better marginal seal than zinc phosphate
Powder composition: 69% ZnO, 29.3% white rosin, 1% zinc stearate, 0.7% zinc acetate
Liquid composition: 85% Eugenol, 15% olive oil
Setting reaction: ZnO + H2O → Zn(OH)2
Manipulation: wet cotton pellet for smoothening, clean up, and hardening of the restoration
Biocompatibility: sedative effect, less irritant to the pulp, antibacterial, pH= 7
Clinical use: temporary cementation, temporary restoration, deep cavity preparation
Advantages: soothing effect on the pulp, good short-term sealing
Disadvantages: high solubility, low strength, low compressive strength, long setting time

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Description

Explore the various types of dental cements used in restorative dentistry, including conventional cement, resin-based cement, zinc phosphate cement, and zinc oxide eugenol. Topics include resistance to solubility, bonding, strength, biocompatibility, working time, and different applications such as temporary and permanent restoration, luting, root canal sealing, and pulp protection.