Dental materials

The FALSE answers about hydrocoloids are:

• Are elastic materials

• The agar-agar impression materials are irreversible hydrocolloids

• Are dimensionally unstable

• The alginates are reversible hydrocolloids

The correct answers about elastomers are:

• Are rubber like materials

• Are reversible

• Are dimensional stable

• Polysilicones are not elastomers

Impression materials are:

• Used in prosthodontics

• Used in endodontics

• Restorative dental materials

• Auxiliary materials

The impression materials are used to:

• Cover an empty space

• Register the forms and the relationships of teeth

• Reproduce the forms and the relationships of teeth

• Al the answers are correct

*The impression materials:

• Cannot be ideal

• Must be nonpoisonous.

• Must be nontoxic

• All the answers are corect

The ideal requirements of the impression materials are:

• Low viscosity

• Chemically inert in oral conditions

• The taste and odour of it are not important

• Low thermal conductivity

*The FALSE answer about the impression materials is:

• The waxes and the compounds can be used as imprrssion materials

• Zinc oxide eugenol is not an impression material

• Alginates are Hydrocolloids

• Can be elastic and nonelastic

Advantages of the Zn OE impressions are:

• Does not adhere well to dried surfaces

• Is dimensionally stable

• Its easy to manipulate

• Its easy to use when we have undercuts

What are the challanges of dental materials in the oral cavity?

• The force of the muscles in the area

• The PH of the saliva

• The fact that there are no enzyme activities

• All the answers above

The impression trays:

• Are only metallic

• Can be reusable

• We cannot individualise a tray

• Support the impression materials