Dental Restorative Materials: Polymerization Shrinkage

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What is the result of inadequate packing pressure on the mold?

Improved coefficiency of thermal contraction

Irregular voids on the surface of the denture (correct)

Uniform polymerization of the acrylic dough

Increased polymerization shrinkage

What is the effect of residual monomer on the denture?

It makes the denture weaker and more flexible (correct)

It has no effect on the denture's properties

It makes the denture stronger and more rigid

It increases the denture's optical properties

What is the primary cause of contraction or shrinkage porosity on the surface of the denture?

Insufficient dough packed in the mould (correct)

Packing before the dough stage

Underpacking of the material

Overpacking of the material

What is the purpose of packing excess acrylic dough?

To decrease polymerization shrinkage from 7% to 0.2% Signup and view all the answers

What is the consequence of under curing the acrylic resin?

High residual monomer in the denture Signup and view all the answers

What is the result of exceeding the boiling temperature of the resin during polymerization?

Gaseous monomer is formed Signup and view all the answers

What is the effect of polymerization on the material's volume?

It decreases the material's volume Signup and view all the answers

What is the result of overheating the acrylic resin during curing?

Formation of gaseous porosity Signup and view all the answers

What is the purpose of ensuring sufficient dough is packed in the mould during denture base manipulation?

All of the above Signup and view all the answers

Why is it important to cool the flask slowly?

To reduce stresses in the denture Signup and view all the answers

What is the result of packing the material before the dough stage?

Rapid loss of pressure occurs Signup and view all the answers

What is the initiator used in the polymerization reaction of PMMA?

Benzoyl peroxide Signup and view all the answers

What is a technique used to reduce polymerization shrinkage?

Using composite inlays Signup and view all the answers

Why is using composite inlays beneficial for patients requiring multiple restorations?

It reduces chair side time Signup and view all the answers

What is the effect of a higher amount of polymer matrix on the thermal coefficient of expansion?

It increases the thermal coefficient of expansion Signup and view all the answers

Which type of composite is more prone to marginal percolation?

Microfilled composite Signup and view all the answers

What is a notable difference in surface finish between microfilled and macrofilled composites?

Microfilled composites can take and retain a smooth surface finish Signup and view all the answers

How do microfilled composites compare to conventional composites in terms of compressive strength?

Microfilled composites have a lower compressive strength Signup and view all the answers