Podcast
Questions and Answers
What is the primary purpose of impression materials in dentistry?
What is the primary purpose of impression materials in dentistry?
Who is the Assistant Professor of Dental Biomaterials at the College of Dentistry?
Who is the Assistant Professor of Dental Biomaterials at the College of Dentistry?
Which role does Dr. Dawlat Mostafa Ahmed also hold in the College of Dentistry?
Which role does Dr. Dawlat Mostafa Ahmed also hold in the College of Dentistry?
What institution does Dr. Dawlat Mostafa Ahmed work at?
What institution does Dr. Dawlat Mostafa Ahmed work at?
Signup and view all the answers
What would be a significant outcome in understanding impression materials for dental practice?
What would be a significant outcome in understanding impression materials for dental practice?
Signup and view all the answers
What distinguishes elastic impression materials from non-elastic impression materials?
What distinguishes elastic impression materials from non-elastic impression materials?
Signup and view all the answers
Which of the following is NOT a type of impression material?
Which of the following is NOT a type of impression material?
Signup and view all the answers
Which property would be most important for an impression material used in a flexible area?
Which property would be most important for an impression material used in a flexible area?
Signup and view all the answers
In which situation would a non-elastic impression material be preferred?
In which situation would a non-elastic impression material be preferred?
Signup and view all the answers
Which is a characteristic feature of elastic impression materials?
Which is a characteristic feature of elastic impression materials?
Signup and view all the answers
What type of tray is typically used for primary impressions?
What type of tray is typically used for primary impressions?
Signup and view all the answers
What is primarily produced from a secondary impression?
What is primarily produced from a secondary impression?
Signup and view all the answers
Which phase follows the primary impression in the impression process?
Which phase follows the primary impression in the impression process?
Signup and view all the answers
Which impression type is associated with the fabrication of restorations?
Which impression type is associated with the fabrication of restorations?
Signup and view all the answers
What distinguishes primary impressions from final impressions?
What distinguishes primary impressions from final impressions?
Signup and view all the answers
Study Notes
Impression Materials
- Impression materials are used to create accurate replicas of oral tissues.
- Impression materials should be non-toxic, non-irritant and have a pleasant odor, taste and color.
- They should be easy to use, have adequate strength.
- Dimensional stability is important.
- They should be compatible with model and die materials.
- Accuracy is crucial in clinical use.
- They should be readily disinfected without loss of accuracy.
Types of Impression Materials
-
Non-Elastic Impression Materials:
- Impression Compound
- Impression Plaster
- Zinc Oxide Eugenol Paste
- Waxes
-
Elastic Impression Materials:
- Hydrocolloids (e.g., Alginate, Agar)
- Elastomers (e.g., Polysulfides, Polyethers, Silicones)
Impression Compound
- Classification: Non-elastic (thermoplastic)
- Supply: Available in sheets and sticks.
- Type I or Low-fusing (55-60 °C)
- Type II or High-fusing (tray materials)
- Composition: Mixture of thermoplastic resins and waxes, fillers(body) and coloring agents (rouge, black, and green).
- Ingredients and their parts are listed in table form
- Reactions: Physical reaction: softening upon heating
- Reversible setting reaction
- Properties:
- Low thermal conductivity
- Softening and flow – Softens just above mouth temperature. Flows sufficiently to register tissues' surface. Hardens at mouth temperature. Minimum flow to reduce distortion on removal from the mouth. -Flow properties at different temperatures are listed in a table
- Poor accuracy and dimensional stability. Release of internal stresses creates warpage
- Equally important: Adequate flow during softening and minimum internal stress
- Uses: Primary impression for completely edentulous patients without undercuts. Border molding.
Zinc Oxide–Eugenol (ZOE) Impression
- Classification: Non-elastic, irreversible
- Supply: Supplied in two paste system (base and accelerator)
- Composition: Base materials (zinc oxide 80%, inert oils 15%) and accelerators (oil of clove or eugenole 15%, gum rosin and oils 65%, fillers 16%, magnesium chloride 4%).
- Reactions: Acid-base reaction (chelation reaction)
- Properties:
- Produces a rigid impression
- Adheres to the tissues.
- Provides good surface detail reproduction in thin section.
- Good dimensional stability (0.1% or less dimensional changes on setting and no significant further changes after 24 hours).
- Stable on storage and has a good life time.
- Uses: Final impression for completely edentulous patients who do not have undercuts.
Question (1): Primary vs. Final Impressions
This section explains the differences between primary and final impressions
Question (2): Advantages and Disadvantages of Impression Compound
This section details the strengths and weaknesses of impression compound
Question (3): Modifying ZOE Setting Time
This question requires students to discover methods to adjust the setting time of ZOE impression pastes.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the essential types and properties of impression materials used in dentistry. This quiz covers both non-elastic and elastic materials, their classifications, and key characteristics necessary for accurate dental impressions. Test your knowledge on this critical area of dental practice.
