EFDA Bases, Liners, and Sealants 5 — Questions and Answers
Question 1: Which of the following clinical scenarios is MOST appropriate for sealant placement?
- A 30-year-old with smooth, well-coalesced occlusal surfaces
- A 7-year-old with newly erupted first molars showing deep fissures (Correct answer)
- A 15-year-old with active interproximal decay in multiple teeth
- An adult with existing amalgam restorations on all posterior teeth
Correct answer: A 7-year-old with newly erupted first molars showing deep fissures
Newly erupted molars in children with deep, caries-susceptible fissures represent the ideal candidate for preventive sealant application.
Question 2: What is the primary reason eugenol-containing temporary cements cannot be used under composite resin restorations?
- Eugenol weakens the composite resin by inhibiting polymerization (Correct answer)
- Eugenol causes pulpal necrosis under composite
- Eugenol prevents the acid etchant from working on enamel
- Eugenol causes composite to discolor permanently
Correct answer: Eugenol weakens the composite resin by inhibiting polymerization
Eugenol is a plasticizer that inhibits the free-radical polymerization of resin composites, leading to incomplete curing and restoration failure.
Question 3: When placing a sealant on a partially erupted molar where the distal portion is still under the operculum, the EFDA should:
- Seal only the erupted portion and recall to seal the rest
- Remove the operculum surgically before sealing
- Defer sealant placement until full eruption to ensure isolation (Correct answer)
- Apply a fluoride varnish as a temporary measure and defer sealing
Correct answer: Defer sealant placement until full eruption to ensure isolation
Adequate moisture control is impossible under an operculum, so sealant placement should be deferred until the tooth is fully erupted and isolation can be achieved.
Question 4: A varnish-type liner such as copal varnish is primarily used under amalgam restorations to:
- Stimulate reparative dentin formation
- Provide thermal insulation equivalent to a base
- Seal dentinal tubules and reduce microleakage initially (Correct answer)
- Increase retention of the amalgam restoration
Correct answer: Seal dentinal tubules and reduce microleakage initially
Copal varnish seals dentinal tubules to reduce early microleakage and fluid sensitivity, though it dissipates as the amalgam margins tighten over time.
Question 5: Which of the following correctly describes the 'sandwich technique' in restorative dentistry?
- Placing amalgam over composite resin for strength
- Using a glass ionomer base beneath composite resin to combine fluoride release with esthetic overlay (Correct answer)
- Applying two layers of sealant for increased retention
- Layering calcium hydroxide, ZOE, and zinc phosphate in deep preparations
Correct answer: Using a glass ionomer base beneath composite resin to combine fluoride release with esthetic overlay
The sandwich technique places a glass ionomer base (for fluoride and adhesion) beneath composite resin (for esthetics and strength) in a single restoration.
Question 6: Hydrophilic pit and fissure sealants were developed to address which common clinical problem?
- Difficulty in light-curing deep fissures
- Sealant failure caused by minor moisture contamination (Correct answer)
- Insufficient fluoride release from resin sealants
- High cost of traditional resin sealant systems
Correct answer: Sealant failure caused by minor moisture contamination
Hydrophilic sealants are designed to bond despite slight moisture contamination, addressing the most common cause of sealant failure in clinical settings.
Question 7: When evaluating a completed sealant clinically, which finding would require immediate repair or replacement?
- Slight opacity compared to the natural tooth color
- Sealant extending slightly onto the buccal cusp incline
- An explorer tip catching or dropping into a void within the sealant (Correct answer)
- The sealant covering the entire occlusal surface
Correct answer: An explorer tip catching or dropping into a void within the sealant
An explorer catching in a void indicates incomplete coverage or air entrapment, creating a site for plaque accumulation and caries initiation under the sealant.
EFDA Bases, Liners, and Sealants 5
Which of the following clinical scenarios is MOST appropriate for sealant placement?