Dental Materials Quiz

Model and Die Materials in Dentistry

• Main requirement: Ability to reproduce fine details in dental models and dies.
• High cost, low mechanical strength, and complex manufacturing process are NOT the main requirements.

Gypsum Products

• Primary Component: Calcium sulfate hemihydrate
• Types:
  • Model Plaster (Type II): Used for general models.
  • Dental Stone (Type III): Used for high-strength applications.
  • Improved Stone (Type IV): Used for higher strength and expansion requirements.
  • High-Strength, High-Expansion Dental Stone (Type V): Used for specific applications requiring high strength and expansion.

Water-to-Powder Ratio for Dental Stone (Type III)

• Ideal ratio: 100 gm powder / 30 ml water

Electroplated Dies

• Advantage: No dimensional change during setting.
• Lower cost, faster manufacturing time, and compatibility with all impression materials are NOT the primary advantages.

Model and Die Dimensional Stability

• Crucial Property: Dimensional stability.
• Flexibility, low cost, and high porosity are NOT crucial properties for avoiding dimensional changes.

Plaster of Paris

• Type: Type II: Model Plaster
• Commonly known as: Plaster of Paris

Calcination Process

• Involves: Removing water of crystallization

Gypsum Calcination Producing Porous Particles

• Type of Calcination: Dry calcination

Gypsum Product Created through Wet Calcination

• Product: Dental Stone (Type III)

Particle Shape in High-Strength Dental Stones

• Shape: Cubic

Function of Excess Water in Gypsum Products

• Function: Creates porosity after evaporation.
• Improving setting reaction and increasing strength are NOT the primary functions of excess water.

Measuring Initial Setting Time of Gypsum

• Method: Vicat test

Disadvantages of Gypsum as a Die Material

• Disadvantage: Susceptibility to abrasion

Calcium Chloride in Gypsum Products

• Reason for Addition: To speed up setting time.
• Increasing cost and improving compressive strength are NOT the primary reasons.

Gypsum Setting Expansion Factors

• Factor: Particle size and shape.
• Water temperature, humidity, and mixing speed are NOT direct factors affecting setting expansion.

Purpose of Vibration in Gypsum Mixing

• Purpose: Preventing the formation of air bubbles.

Abrasion-Resistant Material for Electroplated Dies

• Material: Silver or Copper coating

Impression Materials NOT Suitable with Epoxy Resins

• Material: Hydrocolloid
• Polyether, Silicone, and rubber are not the answer.

Reason Epoxy Resins Favored over Gypsum

• Reason: Abrasion resistance

Gypsum Setting Retarder

• Chemical: Borax

3D Printing Technology for Dental Models

• Method: Stereolithography

Advantage of 3D Printed Dental Models

• Advantage: Precise reproduction of dental anatomy.

Estimating Initial Setting Time of Gypsum

• Method: Loss of gloss

Effect of Increasing Water/Powder Ratio

• Effect: Decreases strength

Accelerator in Gypsum Setting

• Substance: Potassium sulfate

Setting Reaction Mechanism in Gypsum

• Mechanism: Crystalline theory

Anode Material for Silver Plating in Electroplated Dies

• Material: Silver

Disadvantage of Copper-Plated Dies

• Disadvantage: Potential for dimensional instability

Purpose of Adding Fillers to Polyurethane Resin

• Purpose: Reduce polymerization shrinkage

Compatible Impression Material for Flexible Die Materials

• Material: Polyvinyl siloxane

Reason for Using a Mechanical Mixer in Gypsum Products

• Reason: Controls setting temperature and reduces mixing time.

Natural Gypsum Rock Color

• Color: Yellowish-white

Property NOT of Ideal Model and Die Materials

• Property: High porosity

Dry Gypsum Compressive Strength Development Time

• Time: 7 days

Factor Reducing Gypsum Setting Time

• Factor: Vigorous mixing

Effect of Adding Gum Arabic to Gypsum Mixtures

• Effect: Reduces water requirement

Gypsum Product "Densite"

• Type: High-Strength Dental Stone (Type IV)

Significance of 100°C in Gypsum Setting

• Significance: Prevents gypsum from setting

Disadvantage of Hydrocolloid with Epoxy Resins

• Disadvantage: Polymerization reaction is retarded by water.

One Disadvantage of Flexible Die Materials

• Disadvantage: High cost

Factors NOT Affecting Gypsum Setting Expansion

• Factors: Storage container color

Spherulites in Gypsum Setting

• Description: Needle-like crystal clusters

Feature Critical for Fine Detail Reproduction in Model and Die Materials

• Feature: Smooth surface

What Enhances Compatibility of Flexible Dies with Undercut Regions

• Feature: High flexibility

Gypsum Retarder

• Substance: Borax

Recommended Gypsum Type for Study Casts

• Type: Model plaster (Type II)

Common Disadvantage of Epoxy and Polyurethane Resins

• Disadvantage: Water sensitivity in hydrocolloid impressions

Purpose of Vibration Technique in Gypsum Mixing

• Purpose: Remove air bubbles

Advantage of 3D Printed Dental Models for Surgical Simulations

• Advantage: Precise anatomical replication

Factor Increasing Gypsum Setting Expansion

• Factor: Increasing mixing speed

Ideal Powder-to-Water Ratio for High-Strength Dental Stone

• Ratio: 100 gm powder / 22-24 ml water

Humidity Effect on Stored Gypsum Powder

• Effect: Can result in delayed setting time

Gypsum Calcination Method for Uniform Prismatic Particles

• Method: Wet calcination

Effect of Temperature Above 37°C on Gypsum Setting

• Effect: Decreases solubility of dihydrate, slowing setting.

Purpose of Adding Flexible Die Materials

• Purpose: Enables easy fabrication of restorations.

Preferred Material for Casting Metal Frameworks

• Material: High-strength dental stone

Primary Composition of Natural Gypsum

• Composition: Calcium sulfate dihydrate

Gypsum Expansion Type During Setting Under Water

• Type: Hygroscopic expansion

Material Used to Coat Impressions in Electroplating with Copper

• Material: Graphite particles

Initial Setting Time of Gypsum Products

• Time: 8-10 minutes

Advantage of High-Strength, High-Expansion Dental Stone

• Advantage: Suitable for detailed restorations

Lowest Gypsum Product Strength State

• State: Wet

Result of Low Water/Powder Ratio in Gypsum Mixing

• Result: Increased setting time and increased strength and density.

Dimensional Stability in Electroplated Dies

• Method: No expansion or contraction. (No water/powder ratio)

Disadvantage of Copper Electroplating in Dental Dies

• Disadvantage: Limited use with polysulfide impressions

Gypsum Manipulation Primary Purpose of Proportioning

• Purpose: Ensuring correct water/powder ratio.

Factor Directly Influencing Gypsum Hardness

• Factor: Compressive strength

Feature Making Type IV Gypsum Susceptible to Abrasion

• Feature: Dense structure

Situation Where Model Plaster (Type II) is Typically Used

• Situation: Study casts

Component Ensuring Gypsum Wettability on Rubber Impressions

• Component: Vibration during pouring

Effect of Lower Temperatures in Gypsum Setting

• Effect: Prolonged setting time

Sodium Chloride in Gypsum (Low Concentrations)

• Effect: Reduces setting time

How Does Adding Sodium Chloride to Gypsum Affect Setting Expansion?

• Effect: Reduces setting expansion

Common Gypsum Product for Crowns and Bridges

• Type: High-strength dental stone (Type IV)

Common Color of Dental Stone (Type III)

• Color: Yellow

Additive Commonly Used as a Die Hardener

• Additive: Cyanoacrylate

Result of High Water/Powder Ratio in Gypsum Mix

• Result: Increased porosity

Gypsum Product Commonly Used for Crowns and Bridges

• Type: High-strength dental stone (Type IV)

Common Component in 3D Printing Resins

• Component: Acrylonitrile butadiene styrene (ABS)

Gypsum Setting Time Measurement Method

• Method: Gilmore test

High-Strength Stone Readiness Time

• Time: 30 minutes

Disadvantage of Model Plaster (Type II) Compared to Dental Stone

• Disadvantage: Low tensile strength

Factor Crucial for Accurate Dimensional Stability of Gypsum Models

• Factor: Water/powder ratio

Effect of Sodium Sulfate (Low Concentrations) on Gypsum

• Effect: Decreases setting time

Gypsum Calcination Producing Cubic-Shaped Particles

• Calcination Type: Calcination under pressure

Gypsum Pouring Boxing Method Purpose

• Purpose: Containment of gypsum for accurate cast shaping

Ideal Gypsum Mix Consistency

• Consistency: Creamy

Gypsum Setting Expansion Condition

• Condition: Water

Dental Stone (Type III) Preference for Working Casts

• Reason: High strength and accuracy.

Hand Mixing Effect on Gypsum Setting

• Effect: Shortens setting time

Gypsum Setting Accelerator

• Accelerator: Terra alba

Why Polyurethane Resin is Advantageous in Making Dies

• Reason: Low abrasion resistance.

Effect of Adding Potassium Sulfate in Gypsum

• Effect: Reduces setting time

Die Material Commonly Used For Temporary Crowns

• Material: Flexible die materials

Preferred Material for Casting Metal Frameworks

• Material: High-strength dental stone

Type of Expansion in Gypsum Setting

• Type: Linear expansion

Gypsum Powder Storage Reason

• Reason: Avoids exposure to humidity.

Criterion for Final Set Time in Gilmore Test

• Criterion: Needle penetration resistance

Material to Improve Type IV Gypsum Abrasion Resistance

• Material: Silica sol

Setting Time Description for Gypsum Manipulation and Pouring

• Setting Time: Working time

Primary Purpose of Dental Stone (Type IV)

• Purpose: Accurate dies for crowns and bridges

Reason for Adding Water Before Powder in Gypsum Mixing

• Reason: Prevents air bubbles.

Resin Material for Dies with High Filler Content

• Material: Polyurethane resin

Method Measuring Gypsum Setting Time by Loss of Gloss

• Method: Loss of gloss method.

Gypsum Expansion Under Water

• Type: Hygroscopic expansion

Material for Coating Impressions in Electroplating with Copper

• Material: Graphite particles

Gypsum Initial Setting Time Duration

• Duration: 8-10 minutes

Advantage of Using High-Strength, High-Expansion Dental Stone

• Advantage: Suitable for detailed restorations

Lowest Strength State of Gypsum Product

• State: Wet

Low Water/Powder Ratio in Gypsum Mixing Result

• Result: Increased setting time and increased strength and density, decreased hardness.

Achieving Dimensional Stability in Electroplated Dies

• Method: No expansion or contraction. (No water/powder ratio)

Disadvantage of Copper Electroplating for Dental Dies

• Disadvantage: Limited use with polysulfide impressions.

Primary Purpose of Proportioning in Gypsum Manipulation

• Purpose: Ensuring correct water/powder ratio

Factor Directly Affecting Gypsum Material Hardness

• Factor: Compressive strength

Feature Affecting Type IV Gypsum Abrasion Susceptibility

• Feature: Dense structure

Typical Situation Using Model Plaster (Type II)

• Use: Study casts

Component Improving Gypsum Wettability on Rubber Impressions

• Component: Vibration during pouring

Effect of Lower Temperatures on Gypsum Setting

• Effect: Prolonged setting time

Effect of Adding Sodium Chloride in Small Amounts to Gypsum Setting Expansion

• Effect: Reduces setting expansion

Test your knowledge on dental materials, including copper-plated dies, gypsum, impression materials, and more. This quiz covers critical aspects of dental technology and the properties of various materials used in dentistry.