Material Selection & Aesthetic Customization Flashcards

Which ceramic surface treatment increases the bond strength of feldspathic or glass-ceramic restorations to resin cement?

Answer: Etching with hydrofluoric acid followed by silane application

HF acid etching creates micromechanical retention on glass-ceramic surfaces, and silane coupling agent then provides a chemical bond to resin cement.

In characterizing aged or worn anterior teeth, which surface texture technique on ceramic best replicates the flattened, worn incisal edge?

Answer: Flattening the incisal surface and reducing surface luster in that zone

Aged teeth exhibit worn, flat incisal edges with reduced gloss; replicating this in ceramic requires contouring and selective surface deglossing at the incisal.

Which factor most commonly causes chipping of veneering ceramic from a zirconia framework in clinical service?

Answer: CTE mismatch between zirconia and veneering ceramic creating residual tensile stress

The CTE of zirconia (~10.5 ppm/°C) can differ from veneering porcelain, generating tensile residual stresses in the veneer layer upon cooling, leading to chipping.

When shade-taking for an anterior ceramic restoration, at what time of day and for how long should the initial shade observation be made?

Answer: In natural light or balanced light for 5 seconds before eye fatigue sets in

Shade selection should occur in natural or balanced lighting for only a few seconds because color receptors fatigue rapidly, distorting perception.

For a patient with a natural tooth shade of VITA A3.5, which ceramic modification most effectively increases the final restoration's value without changing hue?

Answer: Incorporating more opacifying agents or opal modifiers to lighten the ceramic body

Adding opacifying modifiers scatters more light within the ceramic body, raising the overall value (lightness) while keeping the hue constant.

Which type of zirconia is preferred for anterior full-contour monolithic restorations requiring maximum aesthetics?

Answer: 5Y-TZP or multi-layered high-translucency zirconia

5Y-TZP and high-translucency multi-layer zirconia grades have larger cubic-phase content, increasing translucency for anterior aesthetics at some reduction in strength.

A ceramist is asked to match a restoration to a patient's naturally fluorescent dentition. Which additive is incorporated into ceramic powders to replicate this property?

Answer: Rare-earth fluorescent agents such as europium compounds

Rare-earth fluorescent compounds (e.g., europium-doped materials) are added to dental ceramics to replicate the natural blue-white fluorescence of tooth structure under UV light.