Dental Materials & Laboratory Techniques Flashcards
7 cards from real CDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Dental Materials & Laboratory Techniques flashcards as text
Galvanic corrosion in the mouth most likely occurs when:
Answer: Dissimilar alloys with different electrochemical potentials contact each other in saliva
When dissimilar metals touch in an electrolyte like saliva, current flows from the anodic metal to the cathodic metal, causing the anode to corrode.
The angulation of the condylar guidance on a semi-adjustable articulator is set using a:
Answer: Protrusive bite registration
A protrusive bite registration captures the condylar path angle as the mandible moves forward, allowing the articulator's horizontal condylar inclination to be adjusted.
Which statement best describes the difference between burnishing and polishing in metal finishing?
Answer: Burnishing plastically flows and compresses the surface without material removal; polishing removes micro-scratches by abrasion
Burnishing compresses and flows surface metal to fill micro-defects, while polishing uses progressively finer abrasives to remove surface material and reduce roughness.
The agar hydrocolloid impression material must be maintained in a conditioning bath at approximately:
Answer: 60–65°C (140–150°F)
Agar is stored in a conditioning bath at 60–65°C to keep it in the sol (fluid) state, ready for syringing or loading into a tray.
When constructing a partial denture framework, which survey line determines the path of insertion?
Answer: The survey line established at the chosen path of insertion angle by the surveyor
The surveyor draws a line at the greatest convexity of each abutment tooth for the selected tilt, defining retentive and reciprocal clasp arm positions.
A technician observes crazing (surface cracks) in a heat-processed acrylic denture base. This is most likely caused by:
Answer: Rapid cooling after deflasking while still hot
Crazing occurs when thermal stresses exceed the material's strength; rapid quenching after processing induces steep temperature gradients that crack the surface.
The primary reason for using an anti-flux when soldering dental alloys is to:
Answer: Prevent solder from flowing onto areas where bonding is not desired
Anti-flux (such as iron rouge or graphite) is applied to areas adjacent to the joint to block solder flow and keep the solder confined to the intended gap.