EFDA Amalgam and Composite Restorations 5 — Questions and Answers
Question 1: Which symptom is MOST consistent with microleakage around a composite restoration?
- Immediate sharp pain upon placement
- Recurrent caries at the restoration margin months later (Correct answer)
- Swelling of the adjacent gingiva
- Fracture of the cusp
Correct answer: Recurrent caries at the restoration margin months later
Microleakage allows bacteria and oral fluids to seep under the restoration margin, leading to secondary (recurrent) caries over time.
Question 2: The proper technique for burnishing an amalgam restoration just before initial set is called:
- Pre-carve burnishing (Correct answer)
- Post-carve burnishing
- Final polishing
- Matrix adaptation
Correct answer: Pre-carve burnishing
Pre-carve burnishing is performed with a large burnisher to adapt amalgam to cavity walls and develop a mercury-lean surface layer before carving.
Question 3: Composite restorations are contraindicated in patients who:
- Have multiple amalgam restorations
- Cannot maintain adequate moisture control or have a known methacrylate allergy (Correct answer)
- Require posterior restorations only
- Are over 50 years of age
Correct answer: Cannot maintain adequate moisture control or have a known methacrylate allergy
Composite bonding requires a dry field; poor moisture control leads to bond failure, and methacrylate allergy is a contraindication to resin-based materials.
Question 4: When adapting gingival margins of an amalgam Class II restoration, which instrument is MOST appropriate?
- Hatchet
- Gingival margin trimmer (Correct answer)
- Spoon excavator
- Cleoid-discoid carver
Correct answer: Gingival margin trimmer
Gingival margin trimmers are designed to bevel and smooth the gingival floor and walls, creating proper margin angles in Class II preparations.
Question 5: Which of the following BEST describes the purpose of polishing an amalgam restoration 24 hours after placement?
- Increase the compressive strength of the amalgam
- Remove surface tarnish and reduce plaque retention by smoothing the surface (Correct answer)
- Bond the amalgam to the tooth structure
- Eliminate mercury from the surface
Correct answer: Remove surface tarnish and reduce plaque retention by smoothing the surface
Polishing an aged amalgam removes surface irregularities and tarnish, producing a smooth surface that is more resistant to corrosion and plaque accumulation.
Question 6: A self-etch adhesive system differs from a total-etch system in that it:
- Requires a separate phosphoric acid etching step
- Simultaneously conditions and primes dentin without a separate etch step (Correct answer)
- Produces stronger bonds to enamel
- Requires light curing of the etchant
Correct answer: Simultaneously conditions and primes dentin without a separate etch step
Self-etch adhesives contain acidic monomers that etch and prime simultaneously, simplifying placement but generally producing weaker enamel bonds than total-etch.
Question 7: The EFDA should inform the dentist if, during composite finishing, the restoration feels 'soft' or scratches easily because this indicates:
- The composite is over-cured
- Incomplete polymerization requiring additional curing or replacement (Correct answer)
- The shade is incorrect
- The matrix was removed too early
Correct answer: Incomplete polymerization requiring additional curing or replacement
A soft or easily scratched composite surface indicates inadequate polymerization, likely due to insufficient curing time, distance, or light intensity.
EFDA Amalgam and Composite Restorations 5
Which symptom is MOST consistent with microleakage around a composite restoration?