EFDA Provisional Crown Fabrication 4

Question 1

When fabricating a provisional for a patient with known acrylic monomer sensitivity, the BEST alternative material is:

Accepted Answer

Bis-acryl composite resin

Answer

Bis-acryl composite resins contain less free monomer than PMMA and are preferred when patients have sensitivity to methacrylate monomers.

Question 2

The purpose of applying petroleum jelly (Vaseline) to the tooth and adjacent tissues before injecting provisional material is to:

Accepted Answer

Act as a separating medium to prevent adhesion to tissues and teeth

Answer

Petroleum jelly acts as a separator so the provisional material does not adhere to the tooth structure or soft tissue during fabrication.

Question 3

Which of the following is a sign of inadequate curing of a PMMA provisional crown?

Accepted Answer

Tacky or soft surface and persistent monomer odor

Answer

A tacky or soft surface with persistent monomer smell indicates incomplete polymerization, meaning the material has not fully cured.

Question 4

A provisional crown is fractured at the isthmus connecting two pontics in a three-unit fixed partial denture. The MOST likely cause is:

Accepted Answer

Insufficient bulk of material at the connector area

Answer

The connector area must have adequate bulk to withstand occlusal forces; thin connectors are prone to fracture under stress.

Question 5

When seating a provisional crown, the patient should be instructed to bite on a cotton roll to:

Accepted Answer

Help fully seat the crown and verify occlusal fit

Answer

Biting on a cotton roll applies even pressure to fully seat the crown and allows the clinician to assess if the occlusion is correct.

(EFDA) Expanded Function Dental Auxiliary Practice Test