18 Questions
What are the two main types of silicone impression materials?
Condensation and addition (vinyl silicone)
What is the composition of the base in a condensation silicone impression material?
Dimethylsiloxane with OH reactive group and reinforcing agent (silica)
What is the role of the accelerator (catalyst) in a condensation silicone impression material?
It is a tin organic ester suspension in alkyl acetate
What is the main reaction that occurs in a condensation silicone impression material?
Cross-linking between the siloxane polymer and alkyl silicate in the presence of tin octate
What is the composition of the base in an addition (vinyl silicone) impression material?
Polymethyl hydrosiloxane with silane terminated silicon and reinforcing filler
What is the main difference between condensation and addition (vinyl silicone) impression materials?
Condensation materials undergo a cross-linking reaction, while addition materials undergo a polymerization reaction
Which disinfectant is recommended for disinfection of polyether impressions?
Iodophor
What is the working time order from highest to lowest for polysulfide, silicones, and polyether materials?
Polysulfide > Silicones > Polyether
What is the correct order of tear strength from highest to lowest for Polysulfide, Addition Silicone, Polyether, and Condensation Silicone?
Polysulfide > Add.Silicone > Polyether > Cond.Silicone
Which impression material requires immersion in iodophor or glutaraldehyde for 10-30 minutes for disinfection?
ZOE
What is the recommended method for disinfection of agar impressions?
Immersing in hypochlorite solution
What are digital impressions also known as?
3-D intraoral scanning
What is a key advantage of automixing when it comes to Polyether rubber impression material?
Provides a more accurate final impression
How can contact between latex gloves and addition silicon material affect the setting process?
Prevent or retard setting by poisoning the platinic catalyst
What is a drawback of Polyether rubber materials compared to condensation silicon?
Shorter working time
How are Polyether rubber impression materials typically supplied for use?
As light, regular, and heavy bodied in two collapsible tubes
What is the primary reason for creating extra space in the impression tray?
To prevent undercuts in the impression
What type of reaction is involved in Polyether rubber impression material setting process?
Addition polymerization reaction
Test your knowledge on the disinfection methods for dental impressions. Learn about neutral, acidic, and specific disinfectants for different types of impression materials such as ZOE, compound, alginate, and agar.
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