Final Exam: Cements, Liners, and Bases

Question 1

What’s the purpose of using a liner in dentistry?

Answer 1

Cover pulp exposure

Question 2

What’s the purpose of using varnishes in dentistry?

Answer 2

• Seal dentin against irritants

- Reduce penetration by oral fluids at the tooth restoration interface

Question 3

Properties of Cements:

To ensure effective adaptation/cementation, what two properties of cement are important in this process?

Answer 3

• • Film thickness and consistency.
    1) Film thickness of a cement has a profound effect on the adaptation of the restoration to the tooth. (ADA Spec No. 96 = 25 µm)
    2) Consistency of the cement and the type of restoration influence the ease with which cement is expressed from under the restoration.

Question 4

Properties of cements:

• • What can you alter to the cement to ensure the most effective adaptation?
• • Heavier consistency creates what kind of film thickness? Is this a good thing or bad thing and why?

Answer 4

• • Changing the powder/liquid ratio
• • Heavier consistency => Greater film thickness => Less complete seating of the restoration
• • Bad! (Less complete seating of the restoration)

Question 5

List certain things that will provide the ultimate film thickness to allow for complete seating of the restoration:

Answer 5

– Particle size of the powder
– Concentration of the powder in the liquid
– Viscosity of the liquid
– Consistency of the cement
– Amount of force applied at cementation
– Consistency of the cement and the type of restoration influence the ease with which cement is expressed from under the restoration
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(Just imagine yourself trying to cement a crown onto a prep tooth… What kind of powder and liquid ratio and force would you want to place onto that crown so that it gets completely stuck onto the tooth…. understand it and then you won’t have to memorize this whole answer list :) ).