EFDA Bases, Liners, and Sealants 2 — Questions and Answers
Question 1: Which liner material releases fluoride ions to help prevent secondary caries beneath a restoration?
- Zinc phosphate cement
- Calcium hydroxide
- Glass ionomer liner (Correct answer)
- Zinc oxide eugenol
Correct answer: Glass ionomer liner
Glass ionomer liners release fluoride, which provides ongoing anticaries protection at the tooth-restoration interface.
Question 2: What is the primary purpose of placing a base under a deep amalgam restoration?
- To improve marginal seal
- To provide thermal insulation and pulpal protection (Correct answer)
- To increase retention form
- To etch the dentin surface
Correct answer: To provide thermal insulation and pulpal protection
A base provides thermal insulation to protect the pulp from temperature changes conducted through the metal restoration.
Question 3: A pit and fissure sealant is indicated when the fissure morphology is:
- Shallow and self-cleansing
- Broad and easy to access with a toothbrush
- Deep and narrow, retaining plaque and debris (Correct answer)
- Already showing early carious lesions visible on radiograph
Correct answer: Deep and narrow, retaining plaque and debris
Deep, narrow pits and fissures that cannot be cleaned by toothbrushing are the primary indication for sealant placement.
Question 4: Which material is contraindicated as a liner directly over a pulp exposure because of its low pH?
- Calcium hydroxide
- Glass ionomer
- Zinc phosphate cement (Correct answer)
- Resin-modified glass ionomer
Correct answer: Zinc phosphate cement
Zinc phosphate cement has a very low initial pH (around 3.5) that can cause pulpal irritation and is contraindicated near direct pulp exposures.
Question 5: When applying a resin sealant, moisture contamination before light curing will most likely cause:
- Faster polymerization
- Sealant discoloration
- Poor adhesion and early sealant loss (Correct answer)
- Increased fluoride release
Correct answer: Poor adhesion and early sealant loss
Moisture contamination disrupts the bond between the etched enamel and the resin sealant, leading to microleakage and early failure.
Question 6: Dentin bonding agents used under composite restorations serve primarily to:
- Replace the need for a base or liner entirely
- Seal the smear layer and bond resin to tooth structure (Correct answer)
- Stimulate reparative dentin formation
- Neutralize acid from composite resins
Correct answer: Seal the smear layer and bond resin to tooth structure
Dentin bonding agents penetrate and seal the smear layer while creating a hybrid layer that bonds resin composite to dentin.
Question 7: Which of the following is a characteristic of zinc oxide eugenol (ZOE) as a temporary base?
- High compressive strength suitable under amalgam
- Sedative effect on the pulp due to eugenol (Correct answer)
- Fluoride release similar to glass ionomer
- Compatibility with all resin composite systems
Correct answer: Sedative effect on the pulp due to eugenol
Eugenol has a sedative, obtundent effect on pulpal tissue, making ZOE useful under painful or sensitive restorations.
EFDA Bases, Liners, and Sealants 2
Which liner material releases fluoride ions to help prevent secondary caries beneath a restoration?