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Questions and Answers
What is the primary characteristic of impression plaster as an impression material?
What is the primary characteristic of impression plaster as an impression material?
Which of the following is NOT a property of ideal impression materials?
Which of the following is NOT a property of ideal impression materials?
What is the primary use of Type I brown cake impression compound?
What is the primary use of Type I brown cake impression compound?
What happens to impression compound when heated?
What happens to impression compound when heated?
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Which ingredient is used in impression compound primarily for lubrication?
Which ingredient is used in impression compound primarily for lubrication?
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What is the setting time range for impression plaster?
What is the setting time range for impression plaster?
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Type II green stick impression compound is primarily used for which purpose?
Type II green stick impression compound is primarily used for which purpose?
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Why is impression material required to have good flow properties?
Why is impression material required to have good flow properties?
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What is the primary characteristic of alginate irreversible hydrocolloid?
What is the primary characteristic of alginate irreversible hydrocolloid?
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What is the recommended action if alginate impressions are not poured within 30 minutes?
What is the recommended action if alginate impressions are not poured within 30 minutes?
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What happens to setting time when using more powder in alginate mixing?
What happens to setting time when using more powder in alginate mixing?
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What is the primary use of light body additional silicone elastomer impression material?
What is the primary use of light body additional silicone elastomer impression material?
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What is a characteristic of Agar reversible hydrocolloid?
What is a characteristic of Agar reversible hydrocolloid?
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Which characteristic is NOT true about putty additional silicone elastomer impression material?
Which characteristic is NOT true about putty additional silicone elastomer impression material?
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In what scenario is Zinc Oxide Eugenol (ZOE) most appropriately used?
In what scenario is Zinc Oxide Eugenol (ZOE) most appropriately used?
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Which type of additional silicone elastomer is most likely to provide excellent surface detail?
Which type of additional silicone elastomer is most likely to provide excellent surface detail?
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What distinguishes the fast-setting alginate from the normal-setting alginate?
What distinguishes the fast-setting alginate from the normal-setting alginate?
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Which feature is NOT associated with alginate?
Which feature is NOT associated with alginate?
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What is one major disadvantage of using additional silicone elastomer materials?
What is one major disadvantage of using additional silicone elastomer materials?
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What is the consequence of leaving an alginate impression for more than 24 hours?
What is the consequence of leaving an alginate impression for more than 24 hours?
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When using medium body additional silicone elastomer material, what is a correct characteristic to note?
When using medium body additional silicone elastomer material, what is a correct characteristic to note?
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What is the primary advantage of using polysulfide elastomer elastic impression material?
What is the primary advantage of using polysulfide elastomer elastic impression material?
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Which of the following is NOT a characteristic of polyether elastomer elastic impression material?
Which of the following is NOT a characteristic of polyether elastomer elastic impression material?
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What is a disadvantage associated with silicone elastomer elastic impression materials?
What is a disadvantage associated with silicone elastomer elastic impression materials?
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What is the typical setting time for polysulfide elastomer elastic impression material?
What is the typical setting time for polysulfide elastomer elastic impression material?
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Which of the following elastomeric materials requires handling with consideration for rapid setting time?
Which of the following elastomeric materials requires handling with consideration for rapid setting time?
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Which elastomeric impression material is known for being used with both stock and special trays?
Which elastomeric impression material is known for being used with both stock and special trays?
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What is the primary benefit of using glutraldehyde in the disinfection of impressions?
What is the primary benefit of using glutraldehyde in the disinfection of impressions?
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Which characteristic is common to both polysulfide and polyether elastomers?
Which characteristic is common to both polysulfide and polyether elastomers?
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Study Notes
Impression Materials
- Impression materials are used to create impressions of teeth and supportive tissues.
- Ideal impression materials are non-toxic and non-irritating (biocompatible).
- They have good flow, easy manipulation, dimensional stability after setting, acceptable price and availability, good shelf life, and pleasant taste, odor, and color.
Types of Impression Materials
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Impression materials are categorized as elastic and non-elastic.
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Non-elastic impression materials include plaster, impression compound, zinc oxide eugenol, and impression waxes.
- Plaster: The earliest impression material used in dentistry, it has limited flow, used for edentulous patients' final impressions and in mild to no undercut conditions.
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Impression compound: One of the oldest impression materials, it's rigid and reversible, thermoplastic. Used in preliminary impressions of edentulous patients, special trays, and border molding. It comes in types I (brown cake) and II (green stick).
- Type I (brown cake): Used for primary impressions in edentulous patients with mild to no undercuts, requiring heat to soften and then cool.
- Type II (green stick): Used for border molding of custom trays, softened by flame, changing from glossy when soft to matte when hard.
- Zinc Oxide Eugenol (ZOE): Used for secondary/final impressions for edentulous patients, offers a sedative effect. It's thin and brittle, used in patients without undercuts, mixed on glass slabs, instead of plaster, and is used on bite registration material.
- Impression Waxes: Thermoplastic materials flowing at mouth temperature, used for correcting small imperfections, typically in combination with other zinc oxide materials.
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Elastic impression materials include hydrocolloids (reversible and irreversible), polysulfides, polyethers, and silicones (condensation and addition).
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Hydrocolloids (reversible): Made from seaweed, reversible (reusable by heating), used to take final impressions.
- Composition: Agar, Borax, Potassium sulfate, Benzoate, Additives.
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Hydrocolloids (irreversible): Replaces agar in modern applications, used for primary impressions (poor detail) with undercut situations.
- Composition: Potassium/sodium triethanolamine alginate, Calcium sulfate dihydrate, Zinc oxide, Potassium titanium fluoride, Diatomaceous earth, Trisodium phosphate, Coloring agents and flavoring agents.
- Polysulfides: Synthetic elastomeric impression materials, supplied in two-paste systems (base/accelerator). Available in various viscosities (light, medium, heavy).
- Polyethers: Elastic impression material suitable for secondary impressions, used in 3 viscosities (light, medium, heavy). Come as a base and accelerator.
- Sillicones (condensation and addition): Used as final impressions using special trays. Available in various body types (light, medium, heavy, putty).
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Hydrocolloids (reversible): Made from seaweed, reversible (reusable by heating), used to take final impressions.
Impression Techniques
- One-step Technique: Mix putty and catalyst, adapt to tray, immediately inject light body around prepared teeth, polymerize simultaneously.
- Two-step Technique: mix putty, adapt to tray and place separator on top, take impression, remove from patient after it sets, remove separator, inject light body, retake impression, wait for setting, and remove.
Impression Materials: Advantages and Disadvantages
- Summarized information about advantages and disadvantages of different materials is available in the text.
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Description
This quiz explores the different types of impression materials used in dentistry, focusing on their characteristics and classifications. Learn about elastic and non-elastic materials, including plaster and impression compounds, and their applications in creating dental impressions.
