EFDA Amalgam and Composite Restorations 2 — Questions and Answers
Question 1: Which type of cavity preparation design is MOST commonly used for amalgam restorations?
- Beveled preparation
- Black's preparation with 90-degree cavosurface margins (Correct answer)
- Chamfer preparation
- Featheredge preparation
Correct answer: Black's preparation with 90-degree cavosurface margins
Amalgam requires a 90-degree cavosurface margin (butt joint) to prevent fracture at the margin, as developed by G.V. Black.
Question 2: When placing a matrix band for an amalgam Class II restoration, the band should be contoured to create:
- A flat contact area
- A convex proximal contour with a tight contact (Correct answer)
- A concave proximal contour
- No contact with the adjacent tooth
Correct answer: A convex proximal contour with a tight contact
The matrix band must be burnished to create a convex proximal surface and a proper tight contact to prevent food impaction.
Question 3: The trituration time for amalgam capsules is controlled to ensure:
- Maximum expansion of the restoration
- Optimal consistency with proper plasticity for condensation (Correct answer)
- Complete elimination of mercury vapor
- Maximum setting time before carving
Correct answer: Optimal consistency with proper plasticity for condensation
Proper trituration time creates the ideal mix consistency — not too dry or too wet — for adequate condensation and adaptation.
Question 4: Which bonding step in composite placement helps prevent post-operative sensitivity?
- Etching for 30 seconds
- Application of a dentinal bonding agent (Correct answer)
- Air drying the preparation completely
- Using a self-curing composite
Correct answer: Application of a dentinal bonding agent
A dentinal bonding agent seals dentinal tubules and bonds the composite to dentin, significantly reducing post-operative sensitivity.
Question 5: The incremental placement technique for composite restorations is used primarily to:
- Speed up the curing process
- Reduce polymerization shrinkage stress (Correct answer)
- Increase the depth of cure
- Eliminate the need for etching
Correct answer: Reduce polymerization shrinkage stress
Placing composite in small increments (≤2mm) reduces the overall polymerization shrinkage stress placed on the bond to tooth structure.
Question 6: When carving an amalgam restoration, the explorer should be drawn along the:
- Center of the restoration only
- Cavosurface margin with one tip on enamel and one on amalgam (Correct answer)
- Occlusal surface in circular motions
- Gingival margin only
Correct answer: Cavosurface margin with one tip on enamel and one on amalgam
Carving at the margin with one tine on enamel and one on amalgam ensures a flush, well-defined margin and removes excess amalgam.
Question 7: Which shade selection guideline should be followed FIRST when choosing a composite shade?
- Select the shade under bright operatory light
- Evaluate shade on a hydrated tooth before isolation (Correct answer)
- Match the shade to the patient's favorite color
- Choose the lightest shade available
Correct answer: Evaluate shade on a hydrated tooth before isolation
Shade selection must be performed on a hydrated tooth before rubber dam or cotton roll isolation, as desiccation lightens tooth color.
EFDA Amalgam and Composite Restorations 2
Which type of cavity preparation design is MOST commonly used for amalgam restorations?