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Questions and Answers
Questions and Answers
What is the primary function of the inert oils in Zinc Oxide-Eugenol impression materials?
What is the primary function of the inert oils in Zinc Oxide-Eugenol impression materials?
- To act as a plasticizer and decrease the irritating action of eugenol (correct)
- To accelerate the setting reaction
- To impart thermoplastic properties to the set impression
- To produce a smoother, more coherent mix
Which component is responsible for imparting thermoplastic properties to the set Zinc Oxide-Eugenol impression?
Which component is responsible for imparting thermoplastic properties to the set Zinc Oxide-Eugenol impression?
- Gum rosin (correct)
- Eugenol
- Accelerator (MgCl2 or CaCl2)
- Zinc oxide
What is the primary component of the base paste (Tube 1) in Zinc Oxide-Eugenol impression materials?
What is the primary component of the base paste (Tube 1) in Zinc Oxide-Eugenol impression materials?
- Eugenol
- Zinc oxide (correct)
- Gum rosin
- Inert oil
What is the purpose of the accelerator (MgCl2 or CaCl2) in Zinc Oxide-Eugenol impression materials?
What is the purpose of the accelerator (MgCl2 or CaCl2) in Zinc Oxide-Eugenol impression materials?
What is the primary function of the filler (talc or kaolin) in Zinc Oxide-Eugenol impression materials?
What is the primary function of the filler (talc or kaolin) in Zinc Oxide-Eugenol impression materials?
What is the main reason for using oil of cloves instead of pure eugenol in Zinc Oxide-Eugenol impression materials?
What is the main reason for using oil of cloves instead of pure eugenol in Zinc Oxide-Eugenol impression materials?
What is the effect of a drop of water or alcohol on the setting time of a zinc oxide-eugenol impression material?
What is the effect of a drop of water or alcohol on the setting time of a zinc oxide-eugenol impression material?
Which of the following statements about the dimensional changes of a zinc oxide-eugenol impression material is correct?
Which of the following statements about the dimensional changes of a zinc oxide-eugenol impression material is correct?
What is the relationship between the flow and setting time of a zinc oxide-eugenol impression material?
What is the relationship between the flow and setting time of a zinc oxide-eugenol impression material?
Which of the following properties of a zinc oxide-eugenol impression material is mentioned in the text?
Which of the following properties of a zinc oxide-eugenol impression material is mentioned in the text?
What is the recommended disinfection procedure for a zinc oxide-eugenol impression material?
What is the recommended disinfection procedure for a zinc oxide-eugenol impression material?
What is the effect of increasing the mixing time within limits on the setting time of a zinc oxide-eugenol impression material?
What is the effect of increasing the mixing time within limits on the setting time of a zinc oxide-eugenol impression material?
Which of the following is a component of zinc oxide-eugenol impression materials?
Which of the following is a component of zinc oxide-eugenol impression materials?
What is the primary role of eugenol in zinc oxide-eugenol impression materials?
What is the primary role of eugenol in zinc oxide-eugenol impression materials?
Which of the following factors can affect the setting reaction of zinc oxide-eugenol impression materials?
Which of the following factors can affect the setting reaction of zinc oxide-eugenol impression materials?
What is the primary advantage of zinc oxide-eugenol impression materials?
What is the primary advantage of zinc oxide-eugenol impression materials?
Which of the following is a disadvantage of zinc oxide-eugenol impression materials?
Which of the following is a disadvantage of zinc oxide-eugenol impression materials?
What is the purpose of zinc oxide in zinc oxide-eugenol impression materials?
What is the purpose of zinc oxide in zinc oxide-eugenol impression materials?
Questions and Answers
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Flashcards
Flashcards
Dental Impression
Dental Impression
A negative replica of hard and soft tissues of the mouth, created with a material that sets while in contact with the tissues.
Cast or Model
Cast or Model
A positive replica of oral structures, created from a dental impression.
Purpose of dental impressions
Purpose of dental impressions
Used to study teeth alignment, construct special trays, treatment planning, and fabricating indirect restorations.
Types of dental trays
Types of dental trays
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Desirable properties of impression materials
Desirable properties of impression materials
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ZOE Composition
ZOE Composition
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ZOE Properties
ZOE Properties
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ZOE Manipulation
ZOE Manipulation
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Factors affecting ZOE setting time
Factors affecting ZOE setting time
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ZOE Advantages
ZOE Advantages
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Ingredient of ZOE base tube
Ingredient of ZOE base tube
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Ingredient of ZOE Accelerator tube
Ingredient of ZOE Accelerator tube
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Temperature effect on setting time
Temperature effect on setting time
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Water/Alcohol effect on setting time
Water/Alcohol effect on setting time
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Inert oils effect on setting time
Inert oils effect on setting time
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Potential side effect of ZOE
Potential side effect of ZOE
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ZOE Limitation
ZOE Limitation
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Flashcards
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Study Notes
Study Notes
Introduction to Impression Materials
- Dental impression is a negative replica of hard and soft tissues of the mouth, made with a material that sets while still in contact with the tooth and tissues.
- A cast (model) is a positive replica of the oral hard or soft structures.
Purpose of Taking Impression
- To study alignment of teeth
- Construction of special (custom) tray
- Treatment planning
- Fabrication of indirect restorations
Types of Trays
- Stock trays
- Special tray
Desirable Properties of Impression Materials
- Pleasant odor, taste, and acceptable color
- Absence of toxic or irritant constituents
- Adequate shelf life for requirements of storage and distribution
- Not expensive
- Easy to use with the minimum of equipment
- Readily wets oral tissues
- Setting characteristics that meet clinical requirements
Zinc Oxide Eugenol (ZOE) Impression Material
Composition
- Tube 1 (Base): 80% Zinc oxide
- Tube 2 (Accelerator): Oil of cloves or eugenol (15%), Inert oil, Gum rosin and oils (65%), Filler (talc or kaolin) (16%), Accelerator (MgCl2 or CaCl2) and water (4%)
Properties
- Non-toxic, but eugenol can be irritant to patients
- Negligible shrinkage (less than 0.1%) during hardening
- Inelastic, cannot be used for recording undercuts
- Adequate working time for border molding in the mouth
- Adequate fine details and dimensionally stable
Manipulation
- Equal length of each paste is dispensed on the mixing pad or glass slap
- Mixed with a stiff stainless steel spatula for approximately 1 minute until a uniform color is achieved
Factors Affecting Setting Time
- Temperature: increased temperature decreases setting time
- Addition of water or alcohol: decreases setting time
- Inert oils: increases setting time
- Ratio of the two pastes: affects setting time depending on the product
- Mixing time: increased mixing time within limits decreases setting time
Advantages
- Adheres well to dried surfaces of compound, resin, and shellac bases
- Sufficient resistance to build up borders if the tray is slightly deficient
- Hard when set, can be taken in and out of the mouth repeatedly
- Can be repaired
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