EFDA Bases, Liners, and Matrices 4

Question 1

A sectional matrix system (e.g., Palodent) is preferred over the Tofflemire system for Class II composites because it:

Accepted Answer

Provides better proximal contact and contour

Answer

Sectional matrix systems produce tighter, more anatomically correct proximal contacts compared to the circumferential Tofflemire band.

Question 2

Copal varnish is applied in a cavity preparation primarily to:

Accepted Answer

Seal dentinal tubules and reduce microleakage under amalgam

Answer

Copal varnish seals dentinal tubules to reduce microleakage and postoperative sensitivity under amalgam restorations.

Question 3

Which matrix system would be MOST appropriate for restoring a severely broken-down molar with missing proximal and buccal walls?

Accepted Answer

Copper band or custom matrix

Answer

A copper band or custom-fabricated matrix is best for teeth with extensive wall loss that standard matrix systems cannot adequately contain.

Question 4

What is the correct consistency of zinc phosphate base when mixed for use as a base (not a luting cement)?

Accepted Answer

Putty-like consistency that holds its shape

Answer

A base consistency for zinc phosphate is thick and putty-like, providing adequate bulk and resistance to compressive forces.

Question 5

The purpose of a wooden or plastic wedge used with a matrix band is to:

Accepted Answer

Separate the teeth slightly and seal the gingival margin

Answer

The wedge separates the teeth to compensate for band thickness and seals the gingival margin to prevent material flash.

(EFDA) Expanded Function Dental Auxiliary Practice Test