Chapter 06 Composites, Glass Ionomers, and Compomers

Chapter 06  Composites, Glass Ionomers, and Compomers

Complete Chapter Questions And Answers
 

Sample Questions

MULTIPLE CHOICE

1. Which of the following is a direct-placement esthetic material?
a.
Composite resin
b.
Silver amalgam
c.
Porcelain inlay
d.
Full gold crown

ANS: A
Composite resin is a direct-placement esthetic material. Direct-placement esthetic materials are those that can be placed directly into the cavity preparation or onto the tooth surface by the clinician without first being constructed outside of the mouth. Esthetic materials are those that are tooth colored.

REF: p. 66 TOP: Direct-Placement Esthetic Restorative Materials

2. Composite resins are composed mainly of an organic resin matrix and inorganic silica filler particles joined together by a _____ coupling agent.
a.
silane
b.
colloidal
c.
surfactant
d.
hydrophobic

ANS: A
Composite resins are composed mainly of an organic resin matrix and inorganic silica filler particles joined together by a silane coupling agent. The silane coupling agent sticks (adheres) the particles to the matrix. Also added are initiators and accelerators that cause the material to set and pigments that give color to the material and match tooth colors.

REF: p. 66 TOP: Composite Resin

3. The fillers used in composite resins are:
a.
bis-GMAs.
b.
inorganic silica particles.
c.
urethane dimethacrylates (UDMAs).
d.
low-molecular-weight monomers called TEGDMAs.

ANS: B
The fillers used in composite resins are inorganic silica particles. Silica may be in crystalline form such as quartz or in noncrystalline form such as glass. The addition of filler particles makes the organic resin stronger and more wear resistant. Fillers also are added to control the handling characteristics of the composite resin and to reduce the shrinkage that occurs when the resin matrix polymerizes, or sets.

REF: p. 66 TOP: Composite Resin (Components)

4. In the polymerization process for composite resins, an activator causes an initiator molecule to form a _____ that breaks one of the carbon-to-carbon double bonds to form a single bond and another free radical.
a.
ketone
b.
γ-phase
c.
eutectic
d.
free radical

ANS: D
In the polymerization process for composite resins, an activator causes an initiator molecule to form a free radical that breaks one of the carbon-to-carbon double bonds to form a single bond and another free radical. That free radical can cause the same reaction with another monomer to add to the polymer chain.

REF: p. 67 TOP: Composite Resin (Polymerization)