DANB Assisting with Restorative and Prosthodontic Procedures 2 — Questions and Answers
Question 1: Which impression material is most commonly used for final impressions in crown and bridge procedures?
- Alginate (irreversible hydrocolloid)
- Zinc oxide eugenol paste
- Polyvinyl siloxane (PVS) (Correct answer)
- Plaster of Paris
Correct answer: Polyvinyl siloxane (PVS)
Polyvinyl siloxane (PVS) and other elastomeric materials are preferred for final impressions because they provide high accuracy and excellent dimensional stability.
Question 2: Why is a temporary (provisional) cement used to seat a temporary crown?
- It is stronger than permanent cement
- It allows easy removal when the permanent crown is ready (Correct answer)
- It bonds chemically to porcelain
- It prevents sensitivity permanently
Correct answer: It allows easy removal when the permanent crown is ready
Provisional cement holds the temporary crown securely during the fabrication period but allows the dentist to remove it easily at the delivery appointment.
Question 3: What is the purpose of a bite registration in a crown and bridge procedure?
- To select the shade of the restoration
- To record the occlusal relationship between upper and lower teeth (Correct answer)
- To take a soft tissue impression
- To measure occlusal bite force
Correct answer: To record the occlusal relationship between upper and lower teeth
A bite registration records the exact opposing relationship of the arches so the dental laboratory can fabricate the crown with correct occlusal contacts.
Question 4: Which of the following is a REMOVABLE prosthodontic restoration?
- Full cast crown
- Fixed partial denture (bridge)
- Complete denture (Correct answer)
- Porcelain onlay
Correct answer: Complete denture
A complete denture is a removable prosthesis that the patient can take out, distinguishing it from fixed restorations that are permanently cemented.
Question 5: What is a 'pontic' in a fixed dental bridge?
- The abutment tooth that supports the bridge
- The artificial tooth that replaces the missing tooth (Correct answer)
- The metal substructure of the bridge
- The connector between the bridge units
Correct answer: The artificial tooth that replaces the missing tooth
The pontic is the artificial tooth component of a bridge that spans the edentulous space, supported by the abutment crowns on either side.
Question 6: When permanently cementing a crown, which items should the dental assistant have prepared?
- Alginate impression trays and material
- Permanent cement mixed to proper consistency and placement instruments (Correct answer)
- Amalgam alloy and mercury capsules
- Composite resin and curing light
Correct answer: Permanent cement mixed to proper consistency and placement instruments
At the crown delivery appointment, the assistant prepares appropriate permanent cement mixed to the correct consistency along with seating and cleanup instruments.
DANB Assisting with Restorative and Prosthodontic Procedures 2
Which impression material is most commonly used for final impressions in crown and bridge procedures?