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

Overfiring causes excessive sintering and crystal growth in the ceramic matrix, resulting in a coarse, rough surface texture known as 'orange peel' or grainy appearance that compromises aesthetics.

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

Surface texture such as perikymata, lobe lines, and stippling should be carved into the green or bisque-fired state before final glaze firing to ensure the texture is permanently incorporated into the ceramic surface.

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

Insufficient dentin layer thickness allows the gray undertone of the opaque porcelain or metallic substructure to influence the overall shade, resulting in a dull, grayish appearance in the final restoration.

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

Internal stratification involves precisely placing porcelains of different optical characteristics (opacity, translucency, fluorescence) in anatomically correct zones to replicate the optical depth of natural dentition.

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

Natural teeth exhibit the greatest translucency at the incisal edge and line angles where enamel is thickest; concentrating translucent porcelain in these zones replicates this optical behavior.

(CDC) Certified Dental Ceramist Practice Test

(CDC) Certified Dental Ceramist Practice Test

CDC Dental Porcelain Layering & Build-Up Techniques 3