CDC Dental Porcelain Layering & Build-Up Techniques 3

Question 1

After multiple firings, a ceramist notices that the porcelain has developed a 'grainy' surface texture. What is the most likely cause?

Accepted Answer

The porcelain was overfired, causing crystal growth and surface roughening

Answer

Too little water was mixed with the porcelain powder

Answer

The restoration was fired in a nitrogen atmosphere

Answer

The glaze was applied too thinly

Question 2

Which method is most appropriate for adding surface texture to a ceramic restoration after bisque bake?

Accepted Answer

Carving texture with instruments or using texture porcelain in the green state before final firing

Answer

Using coarse diamond burs to create horizontal striations

Answer

Applying liquid stains post-glaze without a subsequent firing

Answer

Sandblasting the surface with 110-micron aluminum oxide

Question 3

When layering dentin porcelain over an opaque base, what is a common error that leads to 'grayness' in the final restoration?

Accepted Answer

Applying dentin layers that are too thin, allowing the gray undertone of the opaque to show through

Answer

Applying too much pink modifier to the dentin layer

Answer

Using high-translucency enamel over the dentin

Answer

Firing at temperatures that are too low

Question 4

What technique involves selective application of porcelain with varying degrees of opacity and translucency to mimic the natural depth of tooth structure?

Accepted Answer

Internal stratification

Answer

Monolithic layering

Answer

Flat-plane build-up

Answer

Margin condensation

Question 5

A ceramist is creating a Class IV restoration on a central incisor. Where should the most translucent porcelain be concentrated?

Accepted Answer

At the incisal edge and mesial/distal angles to replicate natural enamel translucency

Answer

At the cervical third near the margin

Answer

At the facial mid-body for maximum light reflection

Answer

Evenly distributed throughout the entire restoration

Question 6

What is the primary risk of applying porcelain layers that are too thick in a single build-up increment?

Accepted Answer

Increased porosity and cracking due to uneven sintering and trapped gases during firing

Answer

The ceramic will not adhere to the substructure

Answer

The restoration will appear too translucent after firing

Answer

Excess shrinkage will not occur, causing the restoration to be over-contoured

Question 7

During the final finishing stage, a ceramist discovers that the glazed restoration has a small area of chipping on the incisal edge. What is the correct repair protocol?

Accepted Answer

Roughen the chipped area, apply add-on porcelain, and perform a repair firing at appropriate temperature

Answer

Apply cyanoacrylate adhesive to bond the chip and return to the patient

Answer

Discard the restoration and fabricate a new one, as fired ceramic cannot be repaired

Answer

Refire at full sintering temperature without adding new porcelain