CDT Crown & Bridge Fabrication 3

Question 1

In a three-unit fixed partial denture, the connector between the retainer and pontic should have a minimum cross-sectional area of approximately:

Accepted Answer

4 mm²

Answer

A minimum connector cross-sectional area of 4 mm² is generally required for anterior bridges, with 9 mm² recommended for posterior units to resist fracture under occlusal load.

Question 2

Which occlusal scheme is most commonly prescribed for implant-supported crowns to minimize off-axis loading?

Accepted Answer

Mutually protected occlusion (canine guidance)

Answer

Mutually protected occlusion (canine guidance) is preferred for implant crowns because it limits lateral forces to natural canines, reducing harmful off-axis loading on the implant.

Question 3

The term 'hygienic pontic' refers to a pontic design that:

Accepted Answer

Spans the edentulous space without contacting the ridge tissue

Answer

A hygienic (also called sanitary) pontic is designed with a space between the pontic and the ridge so that oral hygiene can be maintained easily beneath it.

Question 4

During porcelain firing, what phenomenon causes the porcelain to shrink as it reaches its fusion temperature?

Accepted Answer

Sintering and particle coalescence as glass flows

Answer

Shrinkage during porcelain firing occurs because sintering causes glass particles to coalesce and fuse, reducing the total volume and eliminating interparticle voids.

Question 5

What is the function of opaque porcelain in a porcelain-fused-to-metal (PFM) restoration?

Accepted Answer

To mask the dark metal coping and bond to the alloy oxide layer

Answer

Opaque porcelain masks the dark metal coping and chemically bonds to the oxide layer on the alloy surface, establishing the ceramic-metal bond.

(CDT) Certified Dental Technicians Practice Test

(CDT) Certified Dental Technicians Practice Test

CDT Crown & Bridge Fabrication 3