EFDA Bases, Liners, and Sealants 3 — Questions and Answers
Question 1: Before placing a resin-based pit and fissure sealant, the tooth surface is conditioned with:
- Sodium hypochlorite
- Phosphoric acid etchant (Correct answer)
- Calcium hydroxide paste
- Fluoride gel
Correct answer: Phosphoric acid etchant
Phosphoric acid (usually 35–37%) etches enamel to create microporosities for micro-mechanical retention of the sealant.
Question 2: A glass ionomer base is described as being 'biocompatible' primarily because:
- It contains eugenol which calms the pulp
- Its fluoride content kills bacteria
- Its final pH is close to neutral and it chemically bonds to tooth structure (Correct answer)
- It forms a physical barrier thicker than other bases
Correct answer: Its final pH is close to neutral and it chemically bonds to tooth structure
Glass ionomer's final pH approaches neutral and its chemical adhesion to hydroxyapatite makes it well-tolerated by pulpal tissue.
Question 3: Which sealant type does NOT require a separate curing light and polymerizes through a chemical reaction when two components are mixed?
- Visible light-cured sealant
- Self-etching sealant
- Autopolymerizing (self-cured) sealant (Correct answer)
- Fluoride-releasing sealant
Correct answer: Autopolymerizing (self-cured) sealant
Autopolymerizing sealants undergo chemical polymerization when base and catalyst are mixed, without requiring a curing light.
Question 4: When evaluating a placed sealant, an EFDA uses an explorer to check for:
- Fluoride release levels
- Tactile retention and absence of voids or lifted margins (Correct answer)
- Proper color match to the tooth
- The thickness of the sealant layer
Correct answer: Tactile retention and absence of voids or lifted margins
An explorer is used to confirm that the sealant is firmly retained and that there are no voids, bubbles, or lifted edges that could allow leakage.
Question 5: In a very deep preparation approaching the pulp, the FIRST material placed is typically:
- Amalgam condensed directly
- A layer of calcium hydroxide over the deepest point (Correct answer)
- A thick zinc phosphate base
- An acid etch followed by bonding agent
Correct answer: A layer of calcium hydroxide over the deepest point
Calcium hydroxide is placed first over the deepest area closest to the pulp to stimulate secondary dentin and protect pulpal tissue.
Question 6: Which property of calcium hydroxide makes it effective for indirect pulp capping?
- High compressive strength
- Its alkalinity stimulates the formation of reparative dentin (Correct answer)
- Its adhesion to enamel prevents microleakage
- Its radiopacity allows easy radiographic evaluation
Correct answer: Its alkalinity stimulates the formation of reparative dentin
Calcium hydroxide's high pH (around 11–12) causes mild pulp irritation that stimulates odontoblasts to produce reparative (tertiary) dentin.
Question 7: Placing a sealant on a tooth that already has an incipient interproximal lesion visible radiographically is considered:
- The preferred preventive treatment
- A contraindication because the sealant cannot access interproximal surfaces (Correct answer)
- An acceptable alternative to fluoride varnish
- Effective as long as the sealant extends interproximally
Correct answer: A contraindication because the sealant cannot access interproximal surfaces
Pit and fissure sealants are placed on occlusal surfaces and cannot treat or adequately seal interproximal lesions, which are a contraindication.
EFDA Bases, Liners, and Sealants 3
Before placing a resin-based pit and fissure sealant, the tooth surface is conditioned with: