help with the question!!!!

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mesh

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Which of the folllowing statements describe composite resins
I They can be placed and finished in the same appointment.
II. They are more color stable than unfilled resins.
III. They are similar to Amalgam with respect to coefficient of Thermal expansion.
IV. The finished surface tends to be somewhat rough.


3rd option is wrong for sure
so is the 4th. ......HELP
 

LKY

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Which of the folllowing statements describe composite resins
I They can be placed and finished in the same appointment.
II. They are more color stable than unfilled resins.
III. They are similar to Amalgam with respect to coefficient of Thermal expansion.
IV. The finished surface tends to be somewhat rough.


3rd option is wrong for sure
so is the 4th. ......HELP

Well, I am trying to answer this question
I. Yes..all you guys know that composite can be placed and finished in the same appontment.
II. Yes..Unfilled resin have a similar composition with a self-curing resin, because of its lack of color stability and strength, later on, in the development of the material, heat-curing resing were introduced for the material used for acrylic denture.
III. NO...Coef of thermal expansion is a tendency of a material to change in shape when it subject to temperature changes. Direct gold have almost similar coef of thermal expansion with tooth; Composite and amalgam are almost similar - but not similar (composite seems to be higher than amalgam - 28-35;22-28 ppm/cx10, respectively) and unfiller resin is the highest in term of coef of thermal expansion.
IV. Yes..Composite materials finishing surface tends to be rough because of it filler particle contain...

So the answer seems to be I, II and IV are right.
 
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