EFDA Amalgam and Composite Restorations 3 — Questions and Answers
Question 1: A 'high' amalgam restoration on occlusal check reveals a shiny spot on the restoration. This indicates:
- The amalgam is fully cured
- A premature occlusal contact that needs adjustment (Correct answer)
- The restoration was over-polished
- Normal appearance of a new amalgam
Correct answer: A premature occlusal contact that needs adjustment
A shiny spot (burnish mark) from articulating paper indicates a high spot that must be adjusted to prevent fracture or patient discomfort.
Question 2: Which composite resin type provides the BEST wear resistance for posterior occlusal restorations?
- Microfill composite
- Flowable composite
- Hybrid or nanohybrid composite (Correct answer)
- Unfilled resin
Correct answer: Hybrid or nanohybrid composite
Hybrid and nanohybrid composites contain both large and small filler particles, providing superior strength and wear resistance for posterior teeth.
Question 3: The purpose of placing a liner such as calcium hydroxide in a deep cavity preparation before amalgam is to:
- Improve amalgam retention
- Stimulate secondary dentin formation and protect the pulp (Correct answer)
- Etch the dentin surface
- Eliminate the need for a base
Correct answer: Stimulate secondary dentin formation and protect the pulp
Calcium hydroxide stimulates reparative (tertiary) dentin formation and protects the pulp in areas of near-exposure.
Question 4: When using the acid-etch technique for composite bonding, phosphoric acid is applied to enamel for approximately:
- 5 seconds
- 15–30 seconds (Correct answer)
- 60 seconds
- 2 minutes
Correct answer: 15–30 seconds
Phosphoric acid (35–37%) is applied to enamel for 15–30 seconds to create adequate microporosities for resin tag formation.
Question 5: An EFDA notices the composite restoration has voids after initial cure. The BEST course of action is to:
- Polish the restoration as-is
- Inform the dentist immediately for evaluation and repair (Correct answer)
- Apply more composite over the voids without further etching
- Leave the voids as they will fill with saliva
Correct answer: Inform the dentist immediately for evaluation and repair
Voids compromise restoration integrity and invite microleakage; the dentist must evaluate whether repair or replacement is needed.
Question 6: The purpose of using a Tofflemire matrix system during Class II amalgam placement is to:
- Etch the proximal surface
- Re-establish the missing proximal wall for condensation (Correct answer)
- Provide pulp protection
- Polish the gingival margin
Correct answer: Re-establish the missing proximal wall for condensation
The Tofflemire matrix band temporarily replaces the missing proximal wall so amalgam can be condensed without overhang.
Question 7: Spherical amalgam alloy requires LESS condensation pressure compared to admixed alloy because:
- It contains more mercury
- The spherical particles pack together with less interparticle resistance (Correct answer)
- It has a longer working time
- It expands more on setting
Correct answer: The spherical particles pack together with less interparticle resistance
Spherical particles roll over each other more easily, reducing the condensation force needed while still achieving adequate adaptation.
EFDA Amalgam and Composite Restorations 3
A 'high' amalgam restoration on occlusal check reveals a shiny spot on the restoration.
This indicates: