CDT Dental Materials & Laboratory Techniques 4

Question 1

Which type of articulator replicates all mandibular movements using patient-specific records?

Accepted Answer

Class IV fully adjustable articulator

Answer

A fully adjustable (Class IV) articulator accepts individualized pantographic tracings to reproduce all six degrees of mandibular freedom.

Question 2

What does the term 'noble metal content' refer to in ADA classification of dental casting alloys?

Accepted Answer

The combined percentage of gold, platinum, palladium, and other platinum-group metals

Answer

Noble metal content is the total percentage of gold plus platinum-group metals (platinum, palladium, rhodium, ruthenium, iridium, osmium) in the alloy.

Question 3

Epoxy die materials are superior to gypsum dies in which property?

Accepted Answer

Better dimensional accuracy and abrasion resistance

Answer

Epoxy resin dies exhibit very low setting shrinkage, excellent surface hardness, and high abrasion resistance, making them ideal for precision work.

Question 4

Suck-down (vacuum-formed) thermoplastic trays are most commonly fabricated at a temperature of approximately:

Accepted Answer

130–160°C

Answer

Most thermoplastic tray materials soften adequately for vacuum forming in the 130–160°C range without degrading the material.

Question 5

In ceramics, the term 'leucite' is significant because it:

Accepted Answer

Raises the coefficient of thermal expansion to match metal alloys

Answer

Leucite crystals in feldspathic porcelain increase the coefficient of thermal expansion, matching it more closely to PFM alloys and reducing firing stress cracking.

(CDT) Certified Dental Technicians Practice Test

(CDT) Certified Dental Technicians Practice Test

CDT Dental Materials & Laboratory Techniques 4