CDT Ceramics & Porcelain Techniques Flashcards

What is the function of an 'enamel' or 'incisal' porcelain in a layered ceramic build-up?

Answer: To add translucency and depth to the outer surface, mimicking natural enamel

Incisal/enamel powders are highly translucent and simulate the natural optical depth and light-scattering of tooth enamel.

What causes porcelain to appear 'gray' or 'flat' after firing in a PFM crown?

Answer: Insufficient opaque coverage allowing metal to show through

Inadequate opaque coverage allows the dark metal substrate to show through, graying out the overlying porcelain.

What is 'sintering' in the context of zirconia processing?

Answer: High-temperature densification that transforms porous zirconia into a hard, dense ceramic

Sintering fires zirconia at approximately 1,450–1,530°C, driving off porosity and transforming it into its final, hard, dense form.

Which porcelain defect is characterized by small pits or craters on the fired surface?

Answer: Pinholes (pitting)

Pinholes result from trapped gases escaping during firing, often caused by contamination or improper porcelain condensation.

What does 'chroma' refer to in dental shade selection?

Answer: The saturation or intensity of the hue

Chroma refers to the saturation or strength of the color, indicated by numbers in Vita shades (e.g., A1 = low chroma, A4 = high chroma).

What precaution must be taken when grinding or adjusting ceramic restorations chairside or in the lab?

Answer: Use copious water cooling and wear appropriate respiratory protection

Ceramic dust contains silica and zirconia particles that are hazardous to inhale, requiring water cooling and N95 or better respiratory protection.