Chapter 09 Dental Ceramics

Chapter 09  Dental Ceramics

Complete Chapter Questions And Answers
 

Sample Questions

MULTIPLE CHOICE

1. What is the main advantage of the combination of porcelain and metal for fixed crown and bridge prosthodontics?
a.
Direct fabrication of the restoration in the patient’s mouth
b.
Superior esthetics when contrasted with all-porcelain jacket crowns
c.
The use of high-fusing porcelain for superior bonding to tooth structure
d.
The strength and durability produced by the bond between a metal internal core and the porcelain covering

ANS: D
The main advantage of the combination of porcelain and metal for fixed crown and bridge prosthodontics is the strength and durability given to the restoration by the bond between a metal internal core and the esthetic external porcelain covering. The restorations are strong enough to be used in the posterior part of the mouth, where biting forces are greater than in the anterior, and can be either single crowns or multiple-unit bridges.

REF: p. 139
TOP: Clinical Applications for Ceramic Materials (Porcelain-Metal Restorations)

2. The metals used as the core for the porcelain-fused-to-metal (PFM) crowns are alloys of specific metals that will form a/an _____ layer as the metal is heated.
a.
oxide
b.
eutectic
c.
scintillating
d.
oxygen-inhibited

ANS: A
The metals used as the core for the PFM crowns are alloys of specific metals that will form an oxide layer as the metal is heated. When porcelain is applied to the metal and the two materials are heated together, the porcelain chemically fuses to the oxides on the metal, forming a durable bond.

REF: p. 139
TOP: Clinical Applications for Ceramic Materials (Porcelain-Metal Restorations)

3. The metal in the area of a PFM crown where the porcelain is to be bonded is approximately _____ mm thick.
a.
0.01 to 0.03
b.
0.1 to 0.3
c.
0.3 to 0.5
d.
1.0 to 2.0

ANS: C
The metal in the area of a PFM crown where the porcelain is to be bonded is approximately 0.3 to 0.5 mm thick. This allows for adequate thickness of the porcelain for color and strength.

REF: p. 140
TOP: Clinical Applications for Ceramic Materials (Porcelain-Metal Restorations)

4. Which of the following is the first layer of porcelain applied to the metal during fabrication of porcelain-metal restorations?
a.
Body porcelain
b.
Incisal porcelain
c.
Opaque porcelain
d.
Translucent porcelain

ANS: C
The first layer of porcelain applied to the metal is an opaque porcelain that keeps the oxide color from showing through the porcelain and is the main color used for the crown. Base metals often form darker oxides that are more difficult to hide with the opaque porcelain.

REF: p. 140
TOP: Clinical Applications for Ceramic Materials (Porcelain-Metal Restorations)