CDC Kiln Technology & Firing Protocols Flashcards
6 cards from real CDC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CDC Kiln Technology & Firing Protocols flashcards as text
What effect does repeated firing have on dental feldspathic porcelain?
Answer: Each firing cycle can reduce translucency, alter shade, increase crystallization, and slightly change fit due to further sintering
Each firing subjects the glass matrix to additional thermal cycling, promoting devitrification, pigment degradation, and minor dimensional changes that affect shade and fit.
In a dental kiln, what is devitrification, and why is it undesirable?
Answer: The conversion of the glassy amorphous ceramic matrix into a crystalline structure, causing opaque white patches or loss of translucency
Devitrification converts the transparent glass to an opaque crystalline phase, resulting in white chalky patches and loss of the translucency needed for natural aesthetics.
What is the purpose of the cooling rate control feature in a modern dental kiln?
Answer: A controlled slow cool minimizes residual thermal stresses in the ceramic, reducing the risk of delayed cracking
Rapid, uncontrolled cooling creates large temperature gradients between the surface and interior that generate residual tensile stresses, which can cause immediate or delayed crack propagation.
A ceramist observes a craze or network of micro-cracks on a porcelain crown after cooling. Which factor is most likely responsible?
Answer: Coefficient of thermal expansion mismatch between the porcelain and the substructure or between layers
CTE mismatch generates differential shrinkage stresses during cooling; if the porcelain shrinks at a different rate than the coping or underlying layer, tension cracks form in the weaker ceramic.
Which kiln maintenance practice is most critical for ensuring consistent, reproducible firing results over time?
Answer: Regular calibration using test rings and verification of thermocouple accuracy
Thermocouple drift causes the kiln to fire hotter or cooler than its display indicates; regular calibration with standardized test rings catches this drift before it affects restorations.
Why is it important for a dental ceramist to maintain a firing log recording kiln program settings used for each restoration type?
Answer: To ensure reproducibility across multiple units, track kiln drift over time, and troubleshoot when defects occur
A firing log provides a traceable record that allows the ceramist to reproduce successful results, identify when settings drifted from the baseline, and correlate program changes with defect occurrences.