Deck 16: Polymers for Prosthetic Dentistry

Question 1

Which of the following laboratory devices helps keep the monomer from evaporating during polymerization and creates a denser acrylic?

A) Bunsen burner
B) Pressure pot
C) Lathe
D) Vacuum-forming machine

Answer 1

Pressure pot

Question 2

Which of the following is true of the chairside reline?

A) It utilizes an indirect technique in which an impression of the tissues is made inside the existing denture and a cast is made from this impression.
B) The reline material is applied to the primed denture base and the denture is reseated in the patient's mouth for border molding.
C) An indexing instrument is used to establish the relationship between the cast and the denture.
D) The lining material is heat- and pressure-processed in the denture base.

Answer 2

The reline material is applied to the primed denture base and the denture is reseated in the patient's mouth for border molding.

Question 3

Which of the following is true of long-term soft liners for complete and partial dentures?

A) Long-term liners may not be processed with the application of heat.
B) Silicone long-term liners are less stable over the long term than acrylic long-term liners because they have softeners that leach out.
C) Silicone liners are easy to adjust.
D) Long-term soft liners often do not form a good bond to old acrylic.

Answer 3

Long-term soft liners often do not form a good bond to old acrylic.

Question 4

A specialized aspect of a/an ________________ practice may include the fabrication of maxillofacial prostheses to replace facial tissues lost as the result of trauma, disease, surgery, or birth defect.

A) prosthodontic
B) periodontic
C) endodontic
D) orthodontic

Question 5

Which of the following is true about polymers?

A) They are large, long-chain molecules.
B) They are small, long-chain molecules.
C) They are large, short-chain molecules.
D) They are small, short-chain molecules.

Question 6

Which of the following is true regarding addition polymerization?

A) It occurs in three stages: initiation, margination, and condensation.
B) Monomers have a core of two silicon atoms joined by a double bond.
C) One carbon atom has two hydrogen atoms attached, and the other carbon atom has attached to it one hydrogen atom and one reactive group called a free radical.
D) The reaction produces by-products such as water, hydrogen gas, or alcohol that may compromise the physical properties or handling characteristics.

Question 7

In an addition polymerization reaction, the free radical initiates the reaction by:

A) opening the bond between the two carbon atoms of the monomer
B) creating a bend in the carbon atom
C) excluding divalent cations
D) reversing the polarity of the monomer chain

Question 8

Which of the following is true of in-office care of a complete denture?

A) Patients will not form calculus on a denture.
B) Calculus can be removed by placing the prosthesis in a denture cleaning solution inside a zippered bag placed in an ultrasonic cleaner.
C) It is helpful for the patient if teeth and the acrylic base are worn down during the polishing process.
D) Tissue-bearing surfaces of the complete denture should be polished during cleaning.

Question 9

Polymerization of chemical-cured acrylic resins is set into action when the tertiary amine in the liquid activates the __________ in the powder to produce free radicals.

A) hydroquinone
B) benzoyl peroxide
C) glycol dimethacrylate
D) plasticizers

Question 10

Record bases are used to:

A) obtain secondary impressions for creation of secondary or master casts
B) establish the proper dimension between upper and lower arches
C) obtain final crown and bridge impressions
D) fabricate porcelain veneers

Question 11

The monomer will _____________ if the temperature becomes too great during the polymerization process.

A) cause crazing of the material
B) vaporize and produce porosity
C) bleach the denture white
D) warp the prosthesis

Question 12

Which of the following correctly represents the stages seen when acrylic powder and liquid are mixed together?

A) Stringy, sandy, dough, and rubber
B) Dough, sandy, rubber, stringy
C) Sandy, stringy, dough, and rubber
D) Rubber, stringy, dough, and sandy

Question 13

Which of the following is true regarding the properties of acrylic resins used in dentistry?

A) Heat-cured acrylic resins shrink about 0.6% by volume.
B) The coefficient of thermal expansion of acrylic resins is more than twice that of composite resins.
C) The strength of acrylic resins is comparable with dental amalgam.
D) Denture bases conduct temperature very well.

Question 14

When the acrylic powder and liquid are mixed, the chemical- and heat-cured materials go through a similar reaction, except that chemical-cured materials have a _________ in the liquid as an activator, whereas heat-cured materials do not.

A) benzoyl peroxide
B) hydroquinone
C) glycol dimethacrylate
D) tertiary amine

Question 15

During processing of a denture base, heat-cured acrylic resin in the ________ stage is placed in the space created by removal of the wax and record base.

A) sandy
B) sticky
C) dough
D) rubber

Question 16

Why do some clinicians place three or four 2-mm-diameter holes in the wax spacer in the anterior and posterior ridge regions?

A) The spacer creates a uniform thickness for impression material.
B) The holes help prevent the wax from separating from the stone model.
C) Placing holes creates a mesh for bonding of acrylic to a metal framework.
D) It helps orient the tissue-bearing side of the tray toward the teeth.

Question 17

Which of the following is true of plastic (acrylic) and porcelain denture teeth?

A) Porcelain denture teeth chemically bond to the acrylic base of the denture.
B) It is easier to grind porcelain denture teeth rather than acrylic denture teeth to adjust the occlusion or to reshape a tooth to fit the available space.
C) Plastic denture teeth do not wear the opposing natural or artificial teeth or restorations.
D) Porcelain teeth are used more often than plastic teeth.

Question 18

All of the following are true about cross-linked polymers except:

A) they have short chain atoms attached
B) the bond is stronger and stiffer
C) the bonds are weak
D) the material is not easily manipulated

Question 19

The polymerized acrylic resin formed when a liquid monomer is mixed with a powder of small polymer beads is:

A) bis-GMA
B) benzoyl peroxide
C) poly (ethyl methacrylate)
D) poly (methyl methacrylate)

Question 20

Polymerization shrinkage is seen most readily in which of the following areas of a heat-cured acrylic resin denture?

A) Labial flange
B) Alveolar ridge
C) Palatal
D) Hamular notch

Question 21

Dentures must be relined periodically because:

A) dentures absorb odors from plaque and food
B) alveolar ridges shrink over time
C) dimensional changes in acrylic occur

Question 22

The most common form of polymerization in dentistry is:

A) addition
B) condensation
C) tertiary
D) propagation

Question 23

Sources of dimensional change for polymeric materials include:

A) accelerators and inhibitors
B) coefficient of thermal expansion
C) thermal conductivity
D) water sorption

Question 24

Loss of monomer or inadequate pressure during processing will result in:

A) discoloration of the material
B) a brittle material
C) porosities in the material
D) shrinkage of the material

Question 25

Match the items with the correct description below.
Polymerization

A)A long-chain, high molecular weight molecule produced by linking of many low molecular weight monomer molecules
B)A polymer composed of numerous methyl methacrylate monomers linked together in a long chain
C)The joining of adjacent long-chain polymers by bonding of short chains along their sides
D)The act of forming polymers. The process can be activated by chemicals, heat, or light.
E)Low molecular weight molecules that are joined to form polymers

Question 26

Match the items with the correct description below.
Monomer

A)A long-chain, high molecular weight molecule produced by linking of many low molecular weight monomer molecules
B)A polymer composed of numerous methyl methacrylate monomers linked together in a long chain
C)The joining of adjacent long-chain polymers by bonding of short chains along their sides
D)The act of forming polymers. The process can be activated by chemicals, heat, or light.
E)Low molecular weight molecules that are joined to form polymers

Question 27

Match the items with the correct description below.
Poly (methyl methacrylate)

A)A long-chain, high molecular weight molecule produced by linking of many low molecular weight monomer molecules
B)A polymer composed of numerous methyl methacrylate monomers linked together in a long chain
C)The joining of adjacent long-chain polymers by bonding of short chains along their sides
D)The act of forming polymers. The process can be activated by chemicals, heat, or light.
E)Low molecular weight molecules that are joined to form polymers

Question 28

Denture teeth are usually made of:

A) plastic
B) acrylic
C) porcelain
D) Any of the above

Question 29

Describe how a denture is fabricated using heat-cured resin.

Question 30

Describe the process of addition polymerization.

Question 31

Match the items with the correct description below.
Cross-linked polymers

A)A long-chain, high molecular weight molecule produced by linking of many low molecular weight monomer molecules
B)A polymer composed of numerous methyl methacrylate monomers linked together in a long chain
C)The joining of adjacent long-chain polymers by bonding of short chains along their sides
D)The act of forming polymers. The process can be activated by chemicals, heat, or light.
E)Low molecular weight molecules that are joined to form polymers

Question 32

Match the items with the correct description below.
Polymer

A)A long-chain, high molecular weight molecule produced by linking of many low molecular weight monomer molecules
B)A polymer composed of numerous methyl methacrylate monomers linked together in a long chain
C)The joining of adjacent long-chain polymers by bonding of short chains along their sides
D)The act of forming polymers. The process can be activated by chemicals, heat, or light.
E)Low molecular weight molecules that are joined to form polymers

Question 33

Home care of dentures would include all of the following except:

A) brushing with a denture brush after meals
B) using a denture toothpaste to remove plaque
C) soaking in mouthwash to remove odors
D) soaking in white vinegar to remove calculus

Question 34

All of the following apply to porcelain denture teeth except:

A) they are hard
B) they are esthetic
C) they are easily repaired
D) they are stain resistant

Question 35

Dentures may be customized by:

A) changing acrylic shades to match skin tone
B) recreating diastemas
C) placing restorations in the acrylic teeth
D) All of the above are possible.