20 Questions
What is a disadvantage of polyether rubber impression materials?
Short working time
What is the composition of the base in polyether impression materials?
80% low M.W.polyether liquid polymer and 20% Fillers as silica
What type of polymerization reaction occurs in polyether impression materials?
Addition polymerization
What is a characteristic of polyether impression materials in terms of wetting?
They are highly hydrophilic
What is the dimensional change of polysulfide impression materials during the first 24 hours?
0.3% shrinkage
What is the shrinkage of polyether impressions in the first 24 hours?
0.1%
Why is it recommended to use a non-perforated tray painted with an adhesive material?
To prevent distortion of the impression
What is the elasticity of polysulfide impressions?
98%
Why should rubber impressions be poured 30-60 minutes after removal from the mouth?
To allow for the highest elastic recovery
What is the recommended thickness of a rubber base impression material in a tray?
2-3 mm
What is the primary reason for using a non-perforated tray with an adhesive when taking rubber impressions?
To ensure retention of the impression to the tray and prevent distortion
What happens to rubber impressions after removal from the mouth during storage?
They contract due to further polymerization shrinkage and evaporation of volatile constituents
Which type of rubber impression material is the most flexible?
Polysulfide
Why is it important to pour rubber impressions 30-60 minutes after removal from the mouth?
To allow the highest elastic recovery
What is a characteristic of nanofilled rubber impression materials?
They use silica fillers in a nano size for better flow and details reproduction
What is a key advantage of polyether impressions compared to polysulfides and condensation silicones?
Less dimensional change
Which component of polyether rubber impression materials provides the main setting reaction?
Low M.W. polyether liquid polymer
What type of polymerization process is involved in forming polyether rubber impression materials?
Addition polymerization
How do polyether rubber impression materials cater to different consistencies for various application methods?
By supplying as different consistencies in pastes
What is the primary role of the catalyst in polyether impression materials?
Control setting time
Learn about the advantages and disadvantages of polyether rubber impression materials compared to other types of impression materials. Explore the properties and features of polyether impressions, including their mechanical strength, dimensional stability, working time, and hydrophilicity.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
