Impression Materials 4

The property which ensures good adaptation of the impression material to the oral tissue is

• Dimensional stability

• Elasticity

• Fluidity

• Tear strength

The accuracy of the impression recorded by an elastic impression material is mainly determined by its

• Elastic recovery

• Flexibility

• Tear strength

• Viscosity

The role of filler in impression compound is to

• Increase plasticity of the material in softened state

• Increase the rigidity of material at room temperature

• Lower the fusion temperature of the material

• Lower the viscosity of material above mouth temperature

The following is true about the fusion temperature of impression compound

• Amount of plasticizers present in the compound determines its fusion temperature

• Rigidity decreases as the compound cools below fusion temperature

• The impression compound remains plastic above fusion temperature

• Viscosity decreases as the compound cools below fusion temperature

Impression compound material requires a slow heating process to be converted to a plastic state due to its

• High heat capacity

• High thermal diffusivity

• Low coefficient of thermal expansion

• Poor thermal conductivity

The main reason for the poor dimensional stability of impression compound is

• Expansion on cooling to room temperature

• Polymerization shrinkage during setting

• Relaxation of stresses

• Imbibition of water

The following component is added as a “filler” in impression compound

• Diatomaceous earth

• Resin

• Stearic acid

• Waxes

Compound stick

• Is dimensionally stable

• Can be softened directly over flame

• Is type ll of low fusing material

• Is used to record primary impression of edentulous arches

Impression materials that do not compress the oral tissues during setting or hardening are called ________________.

Name the inelastic Impression material that do not compress the oral tissues during seating of the impression__________