Dental Materials Flashcards
(140 cards)
1
Q
Jello is an example of a/n
A. Reversible hydrocolloid
B. irreversible hydrocolloid
A
Reversible hydrocolloid
2
Q
Alginate is an example of a/n
A. Reversible hydrocolloid
B. irreversible hydrocolloid
A
Irreversible hydrocolloid
3
Q
Hydrocolloid is an example of a/n A. Reversible hydrocolloid
B. irreversible hydrocolloid
A
Irreversible hydrocolloid
4
Q
Instant pudding is an example of a/n
A. Reversible hydrocolloid
B. irreversible hydrocolloid
A
Irreversible hydrocolloid
5
Q
The main potential hazard of mercury hygiene is in the form of mercury vapor
A. True. B. false
A
True
6
Q
Decontamination of a room is possible after a Mercury spill only if the operatory is carpeted
A. True B. false
A
False
7
Q
Cohesive gold is the only metal still used in its pure state in dentistry.
A. True. B. false
A
True
8
Q
TMS pins need to be cemented into place.
A. True. B. false
A
False
9
Q
Posts need to be cemented into place.
A. True. B. false
A
True
10
Q
The best cement to use as a temporary filling on a sensitive tooth is: A.Polycarboxylate cement
B. zinc phosphate cement
C. calcium hydroxide
D. zinc oxide and eugenol
A
Zinc oxide and Eugenol
11
Q
The best cement to use as a base under a permanent filling on a tooth which is not sensitive is: A. Polycarboxylate B. zinc phosphate C. Calcium hydroxide D. Zinc oxide and Eugenol
A
Zinc phosphate
12
Q
The best material to use to cement orthodontic brackets to a tooth is: A. Polycarboxylate B. zinc Phosphate C. Calcium hydroxide D. Zinc oxide and Eugenol
A
Polycarboxylate
13
Q
Zinc oxide and Eugenol can be used as a permanent filling if it is mixed thick.
A. True B. false
A
False
14
Q
Which of the following dental cements is the least irritating to the pulp? A. Calcium hydroxide B. ketac- cem C. Flecks with Vaseline D. Zinc phosphate
A
Calcium hydroxide
15
Q
It is a good idea to line a preparation with cavity varnish before a composite filling is placed on a sensitive tooth.
A. True B. false
A
False
16
Q
What speeds up the formation of secondary dentin? A. Calcium hydroxide B. carboxylate C. Zone D. Zinc phosphate
A
Calcium hydroxide
17
Q
Amalgam may be irritating to the pulp.
A. True
B. false
A
True
18
Q
If there is a small exposure to pulp, the first thing to do would be:
A. Endodontic treatment
B. placement of ZOE
C. Placement of calcium hydroxate
A
Placement of calcium hydroxide
19
Q
After placing ZOE in a tooth that has been sensitive, it is best to wait —- before placing a permanent restoration
A. 3days B. 4 wks
C. 2 wks. D. 3 wks
A
3 weeks
20
Q
If composite is handled with metal instruments, the material may: A. Not be affected B. turn gray C. Turn brown D. Become more brittle
A
Turn gray
21
Q
If polycarboxylate is mixed or handled with metal instruments, the material may: A. Not be affected B. turn gray C. Turn brown D. Become more brittle
A
Not be affected
22
Q
Zinc Phosphate cement is soothing to the pulp.
A. True. B. false
A
False
23
Q
This material is placed on the inner surface of the cavity prep to seal dentinal tubules on the exposed dentin and to prevent marginal leakage.
A. Dycal. B. temprex
C. Flecks D. Copalite
A
Copalite
24
Q
If a patient had a temporary crown seated with temp bond and it came off within a day or two, and the tooth was not sensitive, it should be reseated with:
A. Flecks. B. flecks w/ Vaseline
C. Zone. D. Temrex
A
Flecks w/ vaseline
25
Derlon should be mixed on a glass slab
A. True
B. false
False
26
Para post should be cemented into place with ZOE
A. True
B. false
False
27
Dycal and Zone can be mixed interchangeably.
A. True
B. false
False
28
```
Watercooled trays are used to carry which impression material?
A. Elastomeric material
B. irreversible hydrocolloid
C. Reversible hydrocolloid
D. Impression plaster
```
Reversible hydrocolloid
29
```
Syneresis is the
A. Uptake of water
B. loss of water
C. Expansion of rubber base
D. Amount of elasticity in an impression
```
Loss of water
30
```
Imbibition is the:
A. Uptake of water
B. loss of water
C. Expansion of rubber base
D. Amount of elasticity in an impression
```
Uptake of water
31
```
Under mixing irreversible hydrocolloid impression material results :
A. Grainy mix w/ poor details
B. increased tear strength
C. Increased setting time
D. Finer surface detail
```
A grainy mix with poor detail
32
The effect of zinc oxide and Eugenol on the pulp is:
A. Irritating B. sedating
C. Has no effect
D. To control bleeding
Sedating
33
Why is zinc oxide and eugenol cement mix on a paper pad?
A. To prevent the material from setting too fast
B. To increase the setting time
C. To make cleaning easier
D. To decrease the setting time
To make cleaning easier
34
What is the consistency of zinc oxide and eugenol cement when it is used as a temporary restoration?
A. Fluid. B.firm and brittle
C. Putty-like. D.Smooth and creamy
Putty like
35
```
Zinc phosphate cement may be used as a:
A. Permanent restoration
B. pulp-capping agent
C. Sedative restoration
D. Thermal insulator under
```
Thermal insulator under
36
Access zinc phosphate cement powder left on the mixing slab is:
A. Discarded
B. returned to the bottle
C. Placed under the cement base in the cavity preparation
D. Placed over cement base in the cavity preparation
Discarded
37
Excess ZOE cement powder left on the mixing slab is:
A. Discarded
B. returned to the bottle
C. Placed under the cement base in the cavity preparation
D. Placed over cement base in the cavity preparation
Returned to the bottle
38
Why is it a disadvantage if filling materials are radiolucent?
A. Cannot show the Buccal surface
B. can show how deep decay is
C. Will show clearly on radiograph
D. Difficult to differentiate between restoration and recurrent decay
Difficult to differentiate between restoration an recurrent decay
39
Which would be the restoration of choice for a small cavity on the mesial surface of the maxillary right Central?
A. Amalgam. B. gold inlay
C. Composite. D. Porc jacket
Composite
40
Which would be the restoration of choice, in most cases, to restore a distal occlusal cavity on the maxillary right first molar?
A. Amalgam. B.gold inlay
C.composite. D. Porc jacket
Amalgam
41
Which is the restoration of choice for a right maxillary lateral fractured half the way up the crown.
A. Amalgam. B.gold inlay
C. Composite. D.porc jacket
Porcelain jacket
42
Which is the restoration of choice for a mandibular second molar with the distal buccal cusp missing?
A. Amalgam
B. gold onlay
C. Composite
D. All of the above are of equal quality
Gold onlay
43
What is the most aesthetic material that can be used in fabricating an anterior bridge?
A. Acrylic B. gold
C. Chrome. D. Porcelain
Porcelain
44
```
The chemical used to etch enamel is
A. Zinc oxide
B. methyl Methacrylate
C. Phosphoric acid
D. Eugenol
```
Phosphoric acid
45
```
Preventative sealant resins are place on the:
A. Occlusal surface
B. proximal surface
C. Gingival third
D. Cusp tips
```
Occlusal surfaces
46
```
The most frequent complaint of patients shortly after amalgam restorations are placed is:
A. Pain with percussion
B. An open contact point
C. Malocclusion
D. Numbness around the gingiva
```
Malocclusion
47
```
The polysulfide based materials require mixing together the ----- and the ----- pastes.
A.accelerator, catalyst
B. catalyst, retardant
C.catalyst, base
D. Retardant , accelerator
```
Catalyst, base
48
If _____ is severe, the pulp is continually irritated, may cause the tooth to remain sensitive following placement of the restoration.
A. Acidity. B. galvanic action
C. Mastication. D. Microleakage
Microleakage
49
```
Gutta perchance is used
A. As a dental wax
B. as imp material for gold posts
C. As root canal filling material
D. Occl restoration of molars
```
As a root canal filling material
50
```
One disadvantage of a porc jacket is that it
A. Is not color stable
B. is brittle
C. Has low tensile strength
D. Is irritating to Gingiva
```
Is brittle
51
The ability of material not to become permanently distorted under stress is called.
A.compression B.strain
C.Elasticity. D.Conductibility
Elasticity
52
"Flow" of a material refers to:
A. Continued change of a material under a given load
B. the consistency of a material when mixing
C. The homogeneity of gypsum material
D. Dimensional change of the material during setting
Continued change of the material under a given load
53
```
The stress required to fracture a material by pulling it apart is known as:
A. Compressive strength
B. ductile strength
C. Tensile strength
D. Elastic strength
```
Tensile strength
54
```
Which product undergoes an exothermic reaction when setting?
A. Amalgam
B. zinc oxide-Eugenol
C.composite
D.plaster
```
Plaster
55
```
The impression material capable of change from gel to sol to gel is:
A. Irreversible hydrocolloid
B reversible hydrocolloid
C. Compound
D. Mercaptan
```
Reversible hydrocolloid
56
```
Copper bands are used to carry which impression materials?
A. Stick compound
B. mercaptan
C. Zinc oxide paste
D. Irreversible hydrocolloid
```
Stick compounds
57
"Force" is:
A. Any push or pull upon matter
B. the distortion or change produced in a body as the result of its internal reaction to an external force
C. The internal reaction to an externally applied force
D. Any push upon matter
Any push or pull upon matter
58
"Strain" is:
A. Any push upon matter
B. Any push or pull upon matter C.The distortion or change produced in a body has as the result of its internal reaction to an external force the result of stress
D. The Internal reaction to an externally applied force stress
The distortion or change produced in a body as the result of its internal reaction to an external force the results of stress
59
```
The characteristic of a liquid to flow easily over a surface is:
A. Flow
B. wetting
C. Viscosity
D. Strain
```
Wetting
60
A "gel" is
A. A liquid
B. a colloid in which the dispersing medium is water
C. Suspension of particles in some type of dispersing medium
D. Semi solid colloid
Semisolid colloid
61
```
Sol is
A. Liquid colloid
B. solid colloid
C. Semisolid colloid
D. Suspension of particles in some type of dispersing medium
```
Liquid colloid
62
```
_____ is contraindicated for use under resins and composites.
A. Calcium hydroxide
B. cavity liners
C.cavity varnish
D.a and c
```
Cavity varnish
63
```
____is the process by which mercury and alloy are mixed together .
A. Amalgamation
B. polymerization
C. Trituration
D. Blending
```
Trituration
64
When extruding rubber base impression material, the
A. Base and accelerator are of equal volume
B. base and accelerator are of equal length
C. Amount of each material is not important
D. Base and accelerator are of equal weight
Base and accelerator are of equal length
65
What is the disadvantage of using compound for making impressions of teeth for prepared crowns
A. It is not accurate
B. the result dies lack sufficient detail
C. Pulpal damage may result
D. The compound may not draw
The compound may not draw
66
```
A reason for boxing impressions is:
A: to decrease time necessary for trimming models
B. easy storage
C. Identification
D. To increase the hardness of the model
```
To decrease time necessary for trimming model
67
```
Improved stone is used:
A.to make dies
B. to make study models
C.for bite registration
D. For articulating models
```
To make dies
68
Which cement has the highest compressive strength?
A. ZOE. B. ZOP
C. Polycarboxylate
D. Calcium hydroxide
ZOP
69
```
What is the advantage of using zinc polyacrylate ( poly-carboxylate) cement instead of zinc phosphate cement?
A. Increased tensile strength
B. decreased irritation to pulp
C. Increased crushing strength
D. Increased compression strength
```
Decreased irritation to pulp
70
Which material has the least amount of flow?
A. Acrylic. B. amalgam
C. Cast gold. D. Composite
Cast gold
71
The process of chemically combining monomer and polymer is
A. Plating. B mesmerizing
C. Bonding. D. Polymerization
Polymerization
72
Amalgam restorations.
1. Easily inserted. 2 relatively inexpensive.3 have low thermal conductivity 4 are most frequently used in dentistry.
A. 1,2,3. B. 2,3,4. C. 2,4,5 D. 1,2,4
D. 1,2,4
73
What type of material can be used as a liner under acrylic or composite restorations?
A. Reflect. B. ZOE
C. Vitra-Bond. D. Varnish
Vitra -bond
74
Tarnish and corrosion of amalgam can be reduced by:
A. Polishing the amalgam
B. using a zinc oxide Eugenol base
C. Using a squeeze cloth to remove excess mercury
D. Undertrituration
Polishing the amalgam
75
```
The primary reason for using an individual porcelain jacket is:
A. Amount of overjet
B. esthetics
C. Crushing strength
D. Edge strength
```
Esthetics
76
```
Dissimilar metal restorations in the same mouth can cause pain resulting from difference in:
A. Cavity preparation
B. electrical potential
C. Thermal conductivity
D. Compressive strengths
```
Electrical potential
77
```
This difference in metal material is called.
A. Galvanic shock
B. electrical shock
C. Gold intolerance
D. Metal allergy
```
Galvanic shock
78
```
The oldest impression material is:
A. Impression plaster
B. irreversible hydrocolloid
C. Reversible hydrocolloid
D. Silicone impression material
```
Impression plaster
79
Which material is thermoplastic?
A. Mercaptan B. alginate
C. Compound. D. Plaster
Compound
80
```
One disadvantage of using silicate restoration is:
A. It has fluoride in it
B. shade is difficult to match
C. It is difficult to polish
D. It is water soluble
```
It is water soluble
81
```
Resin is changed from its plastic and easily molded shape into a hardened one by a process called
A. Polymerization
B. adhesion
C. Investment
D. Thermoplastic
```
Polymerization
82
Agar impression materials are examples of ____ hydrocolloids.
A. Reversible. B. irreversible
Reversible
83
Ductility is the ability of a material to withstand permanent deformation under_____ stress without fracture.
A. Compressive b. tensile
C. Shearing
Tensile
84
Malleability is the ability of a material to withstand permanent deformation under ____ stress without rupture.
A. Compressive. B. tensile
C. Shearing
Compressive
85
Durelon is as strong a cement as flecks.
A. True
B. false
False
86
```
Amalgamation takes place when ____ is added to an alloy.
A. Copper
B. mercury
C. Tin
D. Zinc
```
Mercury
87
```
Polymerization takes place in sealants as a result of
A. Heat curing
B. light curing
C. Self curing
D. B and c
E. a and e
```
D . B and c
88
The property of a liquid that causes it to flow easily is called:
A. Wetting. B. viscosity
C. Adhesion. D. None above
Viscosity
89
The setting time of gypsum product may be lengthened or shortened by:
A:mixing speed. B. temperature
C. Water/power ratio
D. All above
All above
90
```
When mixing gypsum products, if the mix is too thick and more water is needed, the result would be:
A. Abnormal mix,decreased strength
B. abnormal mix, increased strength
C. An exceptionally good mix
D. Normal mix
```
Abnormal mix, decreased strength
91
Substances are considered "thermoplastic" because of their ability to.
A. Solidify when cooled because of chem changes
B. be softened when heated because of chem changes
C. Be softened when heated and solidify when cooled with chem changes
D. Be softened when heated and solidify when cooled without chem change
Be softened when heated and solidify when cooled without chem changes
92
A model or replica of a tooth after it has been prepared for an inlay or crown preparation is called a:
A. Pontic B. die
C. Connector D. None above
Die
93
```
Specifications and standards for dental materials are set by the:
A. Dentist.
B. dental pharmacopoeia
C. American Dental Association
D. Council on dental therapeutics
```
American dental association
94
Rubber base (mercaptan) impression material should be mixed in about:
A. One min. B. two mins
C. 30 sec. D. Three min
One minute
95
```
The best thing to use to clean ZOP off with is:
A. Bleach ( hypochlorite)
B. Brillo pad
C. Baking soda
D. Gluteraldehyde
```
Baking soda
96
When mixing zinc phosphate cement, the use of a cool slab is essential because. Give best answer
A. Final mix will be cooler
B. More powder can be incorporated into the mix
C. It allows more control over the work
D. The slab will be easier to clean
More powder can be incorporated into the mix
97
ZOP should be mixed in approximately one minute
| A. True. B. false
False
98
ZOE should be mixed in approximately one minute
| A. True. B. false
True
99
```
For best result, the amalgam restoration should be polished:
A. Immediately
B. at least 12 hrs later
C. 24 to 48 hrs later
D. At least 48 hrs later
```
24 to 48 hrs later
100
Ultimate strength is the point at which stress is too great and the material fractures
A. True. B. false
True
101
In pouring, stone should be added at one corner of an impression to prevent:
A. Air or water from being trapped on the surface of the cast
B. stone of poor quality from being present on the ridge area
C. Artifacts in the body of the cast
Air or water from being trapped on the surface of the cast
102
```
If zinc phosphate cement is mixed to rapidly, it will
A. Not affect its setting time
B. set faster/ decrease its setting time
C. Set slower/ increase its setting time
D. Not set
```
Set fasted/ decrease its setting time
103
```
Zinc phosphate cements should be mixed
A. Over a small area of the slab
B. over a large area of the slab
C. As slowly as possible
D. As quickly as possible
```
Over a large area of the slab
104
```
What material is used for "pulp-capping?"
A. Zinc phosphate
B. calcium hydroxide
C. ZOE
D. Durelon
```
Calcium hydroxide
105
```
During setting, plaster will
A. Cool
B. expand
C. Contract
D. Become thermoplastic
```
Expand
106
Polishing an acrylic resin denture should:
A. Be done at slow speed to prevent overheating
B. leave a high gloss on all surfaces
C. Be confines to peripheries only
Be done at a slow speed to prevent overheating
107
What type of materials emit heat heat during a chemical reaction?
a. exothermic B. hygroscopic C. endothermic. D thermoplastics
Exothermic
108
Why hold a bottle straight up and down when dispensing liquids
A. So it doesn't drip
B. so it doesn't change the size of drop
C. So there's no change in molecular chemistry
D. So you can mi more cement
So it does not change the size of a drop
109
```
What does " amalgamate" mean
A. Squeeze out excess Mercury
B. mull material prior to condensation
C. Measure each substance on the scale
D. Unite a metal alloy with mercury
```
Unite a metal alloy with mercury
110
The laboratory lathe is used primarily to:
A. Trim models. B. polish
C. Reduce wax bulk
D. Sharpen hand cutting instrument
Polish
111
Any full or partial prosthes fabricated of acrylic should be kept submerged water to:
A. Keep it from picking up odors
B. Prevent distortion
C. Maintain color shades
Prevent distortion
112
And acrylic appliance store in a sealed plastic bag prior to delivery from a laboratory in order to avoid
A. Discoloration. B. contamination
C. Distortion. D. All above
All above
113
The ability of a material to withstand permanent deformation, under load without rupture is termed:
A. Tenacity. B. ductility
C. Elasticity. D. Malleability
Malleability
114
In mixing plaster of Paris, which product is stronger, one with,
A. More water
B. less water
Less water
115
```
Increased water in gypsum mix will:
A. Prolong setting time
B. increase the surface hardness
C. Accelerate the setting time reaction
D. Increase the compressive strength
```
Prolong setting time
116
```
When a cavity is close to the Pulpal area, the material used to promote formation of secondary dentin is:
A. Zinc phosphate
B. copalite
C. Cavit
D. Calcium hydroxide
```
Calcium hydroxide
117
```
Zinc oxide and Eugenol cements are used for:
A. Endodontic cementation
B. permanent filling
C. A base for pulp sensitivity
D. Luting permanent restoration
```
A base for pulp sensitivity
118
```
What is the advantage for using glass ionomer cements?
A. Long mixing time
B. Soothing to pulp
C. Easy to manipulate
D. Cariostatic
```
Cariostatic
119
```
What is another advantage to using glass ionomer cements?
A. Temporary cementation
B. slow setting time
C. Easy to clean
D. Chemical bond to dentin and enamel
```
Chemical bond to dentin and enamel
120
```
The bases of trimmed models (study models) should be --- thick.
A. 1/8"
B. 1/4"
C. 1/2"
D. 1"
```
1/2"
121
```
Adding water to a mixture of ZOP will:
A. Contaminate the mix
B. speed up the final set
C. Slow down the final set
D. Not alter the final setting time
```
Speed up the final set
122
What wax do you use to hold pieces of a broken denture together?
A. Utility. B. inlay
C. Compound. D. Sticky
Sticky
123
```
In what order will the asst mix and pass the rubber base material while assisting with an impression for a crown.
1. Load the syringe
2. Mix the heavy body material
3. Mix the light body material
4. Load the custom tray
A. 2,1,3,4. B. 3,4,2,1
C. 3,4,1,2. D. 3,1,2,4
```
D. 3,1,2,4
124
What material will the dentist place first in amalgam preparation that requires minimal pulpal protection?
A. Amalgam. B. varnish
C. Zinc oxide Eugenol
D. Zinc phosphate
Varnish
125
```
The best methods for altering the setting time of irreversible hydrocolloid is to...
A. Change the water/ powder ratio
B. Change the water temperature
C. Change the spatulation time
D. Add an accelerator
```
Change the water temperature
126
```
The sequence in which the following medications should be prepared for treatment in the cavity preparation is.…
1. Calcium hydroxide
2. Varnish
3. Zinc phosphate
A. 1,2,3. B. 2,1,3. C. 3,1,2. D. 3,2,1
```
A. 1,2,3
127
```
While mixing zinc phosphate for cementation of an onlay, the consistency has become too thick. Which of the following should the dental assistant do?
A. Add more liquid
B. Leave out some of the powder
C. Prepare a new mix
D. Decrease spatulation
```
Prepare a new mix
128
```
Which of the following materials is used to stimulate secondary dental formulation?
A. Formocresol
B. cavity varnish
C. Zinc Phosphate
D. Calcium hydroxide
```
Calcium hydroxide
129
```
All of the following may be mixed on the paper pad except:
A. Calcium hydroxide
B. Polycarboxylate cement
C. Zinc Phosphate cement
D. Zinc oxide eugenol cement
```
Zinc Phosphate cement
130
If a reusable capsule with several scratches on the inside is used to triturate amalgam, the new mix may be affected in which of the following ways?
A. It will be unaffected if the scratches are few.
B. it will be contaminated by the previous mix
C. It will have excessive expansion because of the scratches
D. It will have in sufficient expansion because of the scratched
It will be contaminated by the previous mixes
131
Which of the following types of waxes would be the best choice for use on the periphery of an Alginate impression tray?
A. Baseplate wax B. sticky wax
C. Utility wax. D. Impression wax
Utility wax
132
Prior to constructing a custom acrylic tray. Wax may be placed over the study cast to...
A. Absorb heat
B. identify anatomical landmark
C. Provide a spacer for the final impression material
D. Conserve acrylic tray material
Provide spacer for the final impression material
133
In the construction of a custom-made tray, the mixed resin mass should be ----.
A. Sticky. B. doughy
C. Hard. D. Fluid
Doughy
134
Which of the following statements concerning dentures made out of acrylic type resin is true?
A. They may be cleaned with household scouring powder
B. they may be cleaned with soap and water
C. They should be kept dry if stored for long time
D. They should be stores in a container with hot water
They may be cleaned with soap and water
135
The mixing time for most plasters and stones is approximately____.
A. 30sec B. 1 min
C. 3 min D. min
1 minute
136
```
Broken plastic appliances are temporarily repaired with
A. zinc phosphate cement
B.sticky wax
C.chrome cobalt
D. cold cure acrylic
```
COLD CURE ACRYLIC
137
For which impression material is it most critial that a model be poured immediatly
1. Irriversible hydrochloride material
2. . Silicone impression
3. .Reversible hydrocolloid material
4. Rubber base impression
123
138
The mixing time for most plasters and stones is approximately____.
A. 30sec B. 1 min
C. 3 min D. min
1 minute
139
```
Broken plastic appliances are temporarily repaired with
A. zinc phosphate cement
B.sticky wax
C.chrome cobalt
D. cold cure acrylic
```
COLD CURE ACRYLIC
140
For which impression material is it most critial that a model be poured immediatly
1. Irriversible hydrochloride material
2. . Silicone impression
3. .Reversible hydrocolloid material
4. Rubber base impression
123
