Quiz 7 Flashcards
What type of provisional restoration allows the dentist to evaluate the response of the pulp?
Sedative provisional restoration.
By placing a sedative provisional restoration, the dentist is able to evaluate the response of the pulp before reappointment for a permanent restoration.
What could occur if a cast is made from an improperly disinfected impression?
Cannot be disinfected, so start over.
Casts should be completely set and stored for at least 24 hours before disinfecting to prevent attack by chemicals on the surface of the cast.
In most cases, cements have what type of strength and solubility compared to other restorative materials?
Inferior strength and high solubility.
In most cases, cements have inferior strength and high solubility when compared with other restorative materials.
What type of dies can be made using a specially formulated addition silicone material?
Indirect composite inlays.
Some practitioners use a specially formulated addition silicone material in an automatic mixing cartridge system to make dies for indirect composite inlays.
What type of incorporation of zinc phosphate powder is recommended?
Incremental incorporation over a large area.
Incremental incorporation of zinc phosphate powder into the liquid and mixing over a large area of a cooled glass slab are recommended because the chemical reaction is exothermic and produces heat.
Which cement is highest in mechanical strength?
Resin cement.
Resin cement is high in mechanical strength and fracture toughness.
How should zinc phosphate cement be mixed?
In small increments into the liquid.
Zinc phosphate cements are mixed on a cooled glass slab with the powder added slowly in small increments to the liquid.
What oral landmark should a maxillary alginate impression tray extend to include?
Hamular notch.
A properly extended maxillary alginate impression tray will extend posteriorly enough to include the hamular notch.
What is the primary purpose of calcium hydroxide?
Promote reparative dentin.
Calcium hydroxide stimulates secondary dentin when in direct contact with the pulp.
What is the most widely used dental impression material?
Irreversible hydrocolloid.
Alginate, also called alginate hydrocolloid or irreversible hydrocolloid, is by far the most widely used impression material.
Where should the operator stand for a maxillary alginate impression?
Behind the patient at the 11 o’clock position.
The operator stands just behind the patient at the 11 o’clock position while retracting the corners of the mouth.
Which cement should not be used under composites?
Zinc oxide eugenol cement.
Zinc oxide eugenol cement should not be used under composites as it may interfere with the polymerization process of resins.
Which material would not be used as pulpal protection under a restoration?
Resin cement.
Cavity varnish, liners, and bases act as protective layers between the dentin and the restorative material.
How long should impressions taken with polyether be poured?
Within 1 week.
Impressions from this material can be poured up repeatedly for up to a week.
When is zinc polycarboxylate cement no longer usable?
When it loses its gloss and becomes stringy.
Zinc polycarboxylate cement is no longer usable when it loses its gloss and becomes stringy.
What must be done to lower the setting time of certain cements?
Lower the slab temperature.
A lower temperature will slow the setting reaction, giving the clinician more working time.
How should cement be mixed to deliver a permanent crown?
To a luting consistency.
A luting agent is a viscous material placed between tooth structure and a prosthesis.
Why are high-strength bases placed in a thickness of 0.75 mm or greater?
To provide protection from thermal conduction of metal restorations.
High-strength bases provide protection from the thermal conduction of metal restorations.
Why would a dentist choose to use an addition silicone over a condensation silicone?
Addition does not distort as badly.
The addition silicone impression materials provide greater dimensional stability and accuracy.
What is a correct statement regarding alginate hydrocolloid?
Some moisture will be lost from the impression even in 100% humidity.
Fast-set alginate has a working time of 1.25 to 2 minutes.
