EFDA Amalgam and Composite Restorations 4

Question 1

Zinc-containing amalgam alloys should NOT be contaminated with moisture during condensation because this causes:

Accepted Answer

Delayed expansion and post-operative pain

Answer

Moisture contamination of zinc-containing amalgam causes a secondary (delayed) expansion due to hydrogen gas production, which can cause pain and restoration failure.

Question 2

When finishing a composite restoration, the sequence of instruments should generally proceed from:

Accepted Answer

Coarser to finer abrasives

Answer

Finishing proceeds from coarser instruments (carbide finishing burs, coarse discs) to progressively finer polishing instruments to achieve a smooth surface.

Question 3

Which finding after amalgam placement indicates the presence of an amalgam overhang?

Accepted Answer

Floss tears or catches on the gingival margin

Answer

Floss that tears or catches at the gingival margin indicates an amalgam overhang that must be removed to prevent periodontal disease.

Question 4

A Class V composite restoration on the facial surface of tooth #9 requires etching of:

Accepted Answer

Both enamel and dentin (total-etch technique)

Answer

Total-etch technique involves etching both enamel and dentin to maximize bond strength, especially at cervical margins where enamel may be minimal.

Question 5

The 'C-factor' (configuration factor) in composite restorations refers to:

Accepted Answer

The ratio of bonded to unbonded surfaces affecting shrinkage stress

Answer

A high C-factor (more bonded walls than free surfaces) increases polymerization shrinkage stress, which can debond the restoration or fracture enamel.

(EFDA) Expanded Function Dental Auxiliary Practice Test

(EFDA) Expanded Function Dental Auxiliary Practice Test

EFDA Amalgam and Composite Restorations 4