Bases, Liners, and Sealants Flashcards
7 cards from real EFDA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Bases, Liners, and Sealants flashcards as text
Which of the following bases has the highest compressive strength and is most suitable beneath a large amalgam restoration?
Answer: Zinc phosphate cement
Zinc phosphate cement has the highest compressive strength among traditional bases, providing adequate mechanical support under amalgam.
An EFDA notices the sealant appears chalky white and opaque after rinsing the acid etchant. This appearance indicates:
Answer: Proper acid etching has created the correct micro-porous enamel surface
A chalky, frosted white appearance after rinsing is the expected sign that phosphoric acid has correctly etched the enamel surface for bonding.
Resin-modified glass ionomer (RMGI) liners differ from conventional glass ionomer liners primarily in that they:
Answer: Contain resin components allowing light-cured, faster initial set
RMGI contains resin monomers that allow light-cured polymerization for immediate command set, while also undergoing the glass ionomer acid-base reaction.
When mixing zinc phosphate cement for a base, the powder is incorporated into the liquid in:
Answer: Small increments over a large, cool glass slab to dissipate heat
Small powder increments are added gradually to the liquid on a cool glass slab to control the exothermic setting reaction and extend working time.
Which of the following is the correct etch time for permanent enamel when applying a pit and fissure sealant?
Answer: 15–20 seconds
Current clinical guidelines recommend etching permanent enamel for 15–20 seconds to achieve adequate micro-mechanical retention without over-etching.
A liner is different from a base primarily in terms of:
Answer: Thickness — liners are thin coatings while bases are built up for bulk and support
A liner is applied in a thin layer to protect the pulp, whereas a base is applied in greater thickness to provide mechanical support and thermal insulation.
After sealant placement, the patient complains of a high bite on the sealed tooth. The EFDA should:
Answer: Adjust the occlusion with a finishing bur
Excess sealant material that creates a high bite should be reduced using a finishing bur to restore proper occlusal contacts.