Amalgam and Composite Restorations Flashcards

Which type of cavity preparation design is MOST commonly used for amalgam restorations?

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.

When placing a matrix band for an amalgam Class II restoration, the band should be contoured to create:

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.

The trituration time for amalgam capsules is controlled to ensure:

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.

Which bonding step in composite placement helps prevent post-operative sensitivity?

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.

The incremental placement technique for composite restorations is used primarily to:

Answer: Reduce polymerization shrinkage stress

Placing composite in small increments (≤2mm) reduces the overall polymerization shrinkage stress placed on the bond to tooth structure.

When carving an amalgam restoration, the explorer should be drawn along the:

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.

Which shade selection guideline should be followed FIRST when choosing a composite shade?

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.