Cavity Base Materials in Dentistry
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Questions and Answers

What is the purpose of a dental base?

To protect the pulp from thermal changes and occlusal forces.

What are the two most commonly used base materials today?

  • Zinc phosphate cement and composite resin
  • Zinc phosphate cement and glass ionomer cement (correct)
  • Amalgam and composite resin
  • Composite resin and glass ionomer cement

    • A dental base should be toxic to bacteria.

    False (B)

    A dental base should provide a hermetic seal to prevent microleakage.

    <p>True (A)</p> Signup and view all the answers

    A dental base should protect the pulp from electrical and galvanic currents.

    <p>True (A)</p> Signup and view all the answers

    Cavity base materials should not be resistant to chewing pressures.

    <p>False (B)</p> Signup and view all the answers

    A dental base should be radiopaque.

    <p>True (A)</p> Signup and view all the answers

    A dental base should not provide adhesion to the permanent filling material.

    <p>False (B)</p> Signup and view all the answers

    What are the main components of Zinc Phosphate Cement?

    <p>The main components are Zinc Oxide powder (with additives like Magnesium Oxide, Bismuth Oxide, and Silica) and Ortho-phosphoric Acid in liquid form.</p> Signup and view all the answers

    Zinc Phosphate Cement hardens immediately after mixing.

    <p>False (B)</p> Signup and view all the answers

    Zinc Phosphate Cement is preferred as a temporary filling because of its resistance to wear and tear.

    <p>False (B)</p> Signup and view all the answers

    What are the main advantages of Zinc Phosphate Cement?

    <p>Hardens suddenly, provides resistance even at low powder/liquid ratios, and is easily manipulated (C)</p> Signup and view all the answers

    What are some common indications for using Zinc Phosphate Cement?

    <p>Both A and B (B)</p> Signup and view all the answers

    Zinc Phosphate Cement is contraindicated for teeth with deep caries due to its irritant nature.

    <p>True (A)</p> Signup and view all the answers

    Zinc Phosphate Cement is a suitable temporary filling material.

    <p>False (B)</p> Signup and view all the answers

    What is the ideal powder/liquid ratio for Zinc Phosphate Cement?

    <p>The ratio should be according to the manufacturer's instructions. It varies depending on the intended consistency, with a lower ratio for cavity lining putty and a higher ratio for a more fluid luting mix.</p> Signup and view all the answers

    More powder incorporated into the mix will reduce setting time.

    <p>False (B)</p> Signup and view all the answers

    What are the key considerations for mixing Zinc Phosphate Cement?

    <p>The mixing process should be carried out on a clean, cool glass slab with a spatula. The powder should be added gradually to the liquid, and the mixture should be spatulated slowly to dissipate the heat.</p> Signup and view all the answers

    The cavity should be warm before placing Zinc Phosphate Cement.

    <p>False (B)</p> Signup and view all the answers

    What are the main components of Glass Ionomer Cement?

    <p>The main components are a powder mix containing fluoroaluminosilicate glass, aluminium oxide, calcium fluoride, and aluminium fluoride. The liquid is a combination of polyacrylic acid, tartaric acid, and distilled water.</p> Signup and view all the answers

    How is Glass Ionomer Cement classified?

    <p>Glass Ionomer Cement is classified into three types based on its application: Type I for luting crowns and bridges, Type II for aesthetic fillings, and Type III for liners and bases.</p> Signup and view all the answers

    Glass Ionomer Cement provides adhesion solely through chemical bonding.

    <p>False (B)</p> Signup and view all the answers

    A calcium hydroxide primer is always required when using Glass Ionomer Cement.

    <p>False (B)</p> Signup and view all the answers

    What are the main advantages of Glass Ionomer Cement?

    <p>Chemical bonding to the tooth, caries preventive action, thermal compatibility, mild pulp response, and tooth-colored restoration (A)</p> Signup and view all the answers

    What are some indications for using Glass Ionomer Cement?

    <p>All the above (A)</p> Signup and view all the answers

    Powder and liquid should be mixed immediately when using GIC.

    <p>True (A)</p> Signup and view all the answers

    GIC should be protected from moisture during setting.

    <p>True (A)</p> Signup and view all the answers

    Polishing of GIC should be performed immediately after placement.

    <p>False (B)</p> Signup and view all the answers

    What is the main difference between Resin-Modified Glass Ionomer Cement and traditional Glass Ionomer Cement?

    <p>Resin-Modified Glass Ionomer Cement contains resin monomers and photoinitiators alongside the traditional GIC components.</p> Signup and view all the answers

    Resin-Modified Glass Ionomer Cement sets through a single chemical reaction.

    <p>False (B)</p> Signup and view all the answers

    The presence of resins in Resin-Modified Glass Ionomer Cement increases its bonding tendency.

    <p>False (B)</p> Signup and view all the answers

    Resin-Modified Glass Ionomer Cement has a lower initial pH than traditional GIC.

    <p>False (B)</p> Signup and view all the answers

    What are the main advantages of Resin-Modified Glass Ionomer Cement?

    <p>Long working time, good biocompatibility, and resistance to wear and tear (C)</p> Signup and view all the answers

    What are some indications for using Resin-Modified Glass Ionomer Cement?

    <p>Both A and B (D)</p> Signup and view all the answers

    Resin-Modified Glass Ionomer Cement is primarily set by chemical reaction rather than light curing.

    <p>False (B)</p> Signup and view all the answers

    Flashcards

    What is a dental base?

    A dental base is a protective material placed in the cavity preparation, providing thermal insulation and absorbing occlusal forces, preventing pulp sensitivity.

    Which properties should a cavity base material possess?

    Ideally, a cavity base should be bacteriostatic/bactericidal, non-toxic, hermetic, thermally insulating, and protect against irritants and electrical currents.

    What are the main types of cavity base materials?

    Zinc phosphate cement is a traditional material used as a cavity base, but it has been largely replaced by glass ionomer cement.

    How is zinc phosphate cement mixed?

    Zinc phosphate cement is mixed by combining zinc oxide powder and an acidic liquid, creating an exothermic reaction.

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    What is the pH of zinc phosphate cement?

    Zinc phosphate cement has a high initial acidity (pH 3.5) and takes about 24 hours to fully neutralize.

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    Is zinc phosphate cement suitable for temporary fillings?

    Zinc phosphate cement is not ideal for temporary fillings due to its rapid wear and susceptibility to plaque accumulation.

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    What are the advantages of zinc phosphate cement?

    Zinc phosphate cement offers advantages like quick hardening, good strength even with low powder/liquid ratio, and easy manipulation.

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    What are the disadvantages of zinc phosphate cement?

    Zinc phosphate cement has disadvantages like potential pulp irritation, lack of antibacterial action, brittleness, poor adhesion, and solubility in oral fluids.

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    What are the indications for using zinc phosphate cement?

    Zinc phosphate cement is commonly used in various applications, including temporary fillings, bases for permanent fillings, and bonding materials.

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    When is zinc phosphate cement contraindicated?

    Zinc phosphate cement is contraindicated in teeth with deep caries or minimal remaining dentin, as its acidity can irritate the pulp.

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    How does the powder/liquid ratio affect zinc phosphate cement?

    The powder/liquid ratio in zinc phosphate cement determines its consistency and working time. A higher ratio results in a thicker mix and shorter working time.

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    What is glass ionomer cement (GIC)?

    Glass ionomer cement (GIC) is a tooth-colored material that adheres chemically to tooth structure and releases fluoride.

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    How is glass ionomer cement classified?

    Glass ionomer cement is classified based on its application, with Type I being used for luting, Type II for restorations, and Type III for liners and bases.

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    What are the advantages of glass ionomer cement?

    Glass ionomer cement (GIC) has advantages such as chemical bonding to tooth structure, caries prevention, thermal compatibility, mild pulp response, and tooth-colored aesthetics.

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    What are the disadvantages of glass ionomer cement?

    Glass ionomer cement (GIC) has disadvantages like poor mechanical properties (strength, wear resistance), poor esthetics due to translucency, and moisture sensitivity during setting.

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    What factors affect the longevity of GIC restorations?

    The longevity of glass ionomer cement restorations is affected by factors such as occlusal forces, porosities, desiccation, and water absorption.

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    What are the indications for using glass ionomer cement?

    Glass ionomer cement (GIC) is indicated for high-caries-risk patients, restorations in deciduous teeth, root caries, cervical erosion, and various restorative procedures.

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    How is glass ionomer cement mixed?

    Glass ionomer cement (GIC) is mixed by combining powder and liquid in the recommended proportions. The powder is added in increments, and the mixture should be applied quickly.

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    What are the steps involved in the restoration with GIC?

    Glass ionomer cement (GIC) requires a series of steps for its restoration, including cleaning, conditioning, placement, protection, and finishing.

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    What is Resin-Modified Glass Ionomer Cement (RM-GIC)?

    Resin-modified glass ionomer cement (RM-GIC) is a hybrid material that combines the advantages of GIC with the strength and aesthetics of composites.

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    How does resin-modified glass ionomer cement set?

    Resin-modified glass ionomer cement (RM-GIC) is set through a dual-reaction mechanism involving both acid-base and polymerization reactions.

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    What are the advantages of resin-modified glass ionomer cement?

    Resin-modified glass ionomer cement (RM-GIC) offers advantages like biocompatibility, chemical bonding to tooth structure, higher initial pH, and better mechanical properties than conventional GIC.

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    What are the disadvantages of resin-modified glass ionomer cement?

    Resin-modified glass ionomer cement (RM-GIC) has disadvantages like lower mechanical durability than composites and slightly less aesthetic appeal than composites.

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    What are the indications for using resin-modified glass ionomer cement?

    Resin-modified glass ionomer cement (RM-GIC) is indicated for various restorative procedures, including restorations in non-carious cervical lesions and as a liner or base under composite restorations.

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    How is resin-modified glass ionomer cement manipulated?

    Resin-modified glass ionomer cement (RM-GIC) is typically light-cured and can be layered for greater control and reduced shrinkage.

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    Study Notes

    Cavity Base Materials

    • A dental base is a material placed on the floor of a cavity preparation, acting as a protective layer.
    • Its purpose is to insulate the pulp from temperature changes and absorb occlusal forces.
    • It is also used to line areas for indirect restorations such as inlays.
    • Zinc phosphate cement and glass ionomer cement are commonly used.

    Properties of Cavity Base Materials

    • Bacteriostatic/bactericidal to prevent bacterial growth.
    • Non-toxic to avoid damage to hard and soft tissues.
    • Hermetic to prevent microleakage, secondary caries and post-operative sensitivity.
    • Thermally insulating to protect the pulp from temperature fluctuations.
    • Resistance to chewing pressures is essential.
    • Radiopaque for identification in radiographs.
    • Adhesion to the tooth and the permanent filling material.
    • Quick setting at oral temperatures.

    Zinc Phosphate Cement

    • Powder: Zinc oxide, magnesium oxide, bismuth oxide, silica
    • Liquid: Ortho-phosphoric acid, water
    • The alkaline zinc oxide powder and acidic liquid create an exothermic reaction.
    • Acidic (pH 3.5) initially, this property reduces within an hour.
    • Complete neutralization in 24 hours.
    • Not preferred as a permanent filling due to quick breakdown and easy plaque accumulation.

    Advantages of Zinc Phosphate Cement

    • Hardens quickly.
    • Sufficient clinical resistance even with a low powder-liquid ratio.
    • Easy to manipulate.

    Disadvantages of Zinc Phosphate Cement

    • Pulpal irritation.
    • Lack of antibacterial activity.
    • Brittleness.
    • Lack of adhesion.
    • Solubility in oral fluids.

    Indications for Cavity Base Materials

    • Temporary sealing of cavities in permanent teeth.
    • Sealing cavities in deciduous teeth close to falling out.
    • Ensuring permanent fillings are seated properly, distributing forces.
    • Used in the bonding of orthodontic bands, crowns, bridges, and inlays.
    • Used in restoration of decayed teeth prior to crown/bridge fabrication.

    Contraindications for Cavity Base Materials

    • Teeth with minimal dentin above the cavity.
    • Use as a temporary filling material in cases where the cavity extends below the gumline.

    Manipulation of Zinc Phosphate Cement

    • Powder/Liquid ratio based on manufacturer's instructions.
    • Different consistency for lining vs. luting.
    • Powder divided into small increments and mixed slowly.
    • Mixed on a cool, dry glass slab.
    • Working time: 2-3 minutes.
    • Clean glass slab and spatula needed.
    • Mix from powder to liquid.
    • Powder addition must be slow to control setting time.
    • Cement should not stick to the spatula.

    Glass Ionomer Cement (GIC)

    • Powder: Fluoroaluminosilicate glass, aluminium oxide, calcium fluoride, aluminium fluoride, and lithium oxide.
    • Liquid: Polyacrylic acid, tartaric acid, phosphoric acid, and distilled water.

    Classification of GIC

    • Type I: Luting cement
    • Type II: Restorative cement
    • Type III: Liners and Bases

    Advantages of Glass Ionomer Cement (GIC)

    • Chemical bonding to tooth structure.
    • Caries preventive action.
    • Good thermal compatibility.
    • Moderate pulp response.
    • Tooth-colored restorative material.

    Disadvantages of Glass Ionomer Cement (GIC)

    • Lower mechanical durability than composite materials.
    • Aesthetics less than composite.

    Resin Modified Glass Ionomer Cement (RMGIc)

    • Is a hybrid material between traditional glass ionomer cement and resin composite.
    • Characterized by their dual reaction curing mechanism (acid-base & polymerization).
    • Bonding to tooth structure (chemical and mechanical).
    • Improved fluoride release.

    Advantages of Resin Modified Glass Ionomer Cement

    • Easy manipulation.
    • Long working time.

    Disadvantages of Resin Modified Glass Ionomer Cement

    • Lower mechanical properties compared to composites.
    • Less aesthetic compared to composites.

    Indications for RMGIc

    • Class V restorations.
    • Restoration of cervical lesions.
    • Class I and II restorations (primary teeth).
    • Liner and base under composite restorations.

    Manipulation of Resin Modified Glass Ionomer Cement

    • Polymerization by light.
    • Incremental layering
    • Polishing: 24 hour wait preferable.

    Setting Reaction of RMGIc

    • Dual-reaction curing mechanism involving acid-base and polymerization.
    • "Umbrella" effect for moisture protection

    General Notes

    • Proper cleaning and conditioning of the tooth is key
    • Placing and finishing the cement correctly are important steps
    • Protecting the setting cement to ensure proper setting.

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    Description

    Explore the uses, properties, and types of cavity base materials in dentistry, focusing on their role in protecting dental pulp and facilitating restorations. Learn about common materials like zinc phosphate cement and glass ionomer cement, along with their unique qualities.

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