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WorksheetsDental material Interns M C Q 3rd July
Total questions: 50
Worksheet time: 38mins
Name
Class
Date
1.
The decrease in the marginal leakage of an amalgam restoration is primarily the result of
a)
using cavity varnish
b)
water sorption
c)
expansion of the alloy
d)
formation of corrosion products
2.
Wrought gold alloys are used in dentistry primarily as
a)
full crowns
b)
inlays
c)
wires
d)
arch bars
3.
hardness number which does not depend on the ductility of metal
a)
KHN
b)
VHN
c)
RHN
d)
BHN
4.
Ductility of a material is a measure of it's:
a)
Grain elongation
b)
Annealing
c)
Cold working
d)
work hardnening
5.
The stiffness of dental material is determine by its:
a)
proportional limit
b)
modulus of elasticity
c)
ultimate tensile strength
d)
flow
6.
the ability of the base to resist occlusal forces and to support the restoration is affectedby:
a)
modulus of elasticity
b)
tensile strength
c)
youngs modulus
d)
compressive strength
7.
which of the following has the highest modulus of Elasticity
a)
Dentin
b)
enamel
c)
Amalgum
d)
Compositive resin
8.
Munsell System is used to:
a)
Define and measure colour qualitatively
b)
define and measure physical properties of gold alloys
c)
evaluate brittleness of different alloys
d)
measures different colours quantitatively
9.
etching of detin does not include
a)
removal of smear layer
b)
exposure of collagen fibres
c)
opening of dentinal tubules
d)
increases surface energy
10.
the forces that hold atoms together are called
a)
primary forces
b)
secondary forces
c)
cohesive forces
d)
Ionic forces
11.
Coefficient of thermal expansion of tooth enamel is closest to
a)
silicate cement
b)
composite
c)
GIC
d)
polycarboxylate
12.
A good adhesive should posses all of the following Except
a)
High adherend wetting
b)
high contact angle
c)
low contact angle
d)
High flow
13.
the impression with least dimensional change upon disinfection is
a)
additional polysilicone
b)
agar-agar
c)
polysiphide
d)
polyether
14.
Impression plaster is
a)
less compressive than alginate
b)
agar-agar
c)
polysulphide
d)
polyether
15.
The mercury content of the finished amalgam restoration should be approximately
a)
0.4
b)
0.5
c)
0.6
d)
more than 70%
16.
Copper and silver in dental amalgam
a)
increase compressive strength and expansion
b)
aid in amalgamation and decrease expansion
c)
reduce hardness and expansion only
d)
decrease hardness, flow, expansion and compressive strength
17.
When epoxy resins are used for die fabrication, the resultant die will
a)
be slightly undersize
b)
not burn out in the furnace
c)
have poor abrasion resistance
d)
have low strength
18.
Silicate cement powders are made up of oxides or fluorides of all of the following, except<br />FCPS Part 1 Dentistry
a)
aluminium
b)
tin
c)
calcium
d)
silicon
19.
A dental restoration may be tarnished because of
a)
deposition of calculus
b)
surface discoloration
c)
formation of oxides or sulfides
d)
all of the above
20.
The principal hardener in noble metal casting alloys is
a)
brass
b)
iron
c)
copper
d)
silver
21.
Which of the following may result in the expansion of an amalgam restoration made with zinc free<br />alloys?
a)
Moisture contamination during conden-sation
b)
High alloy/mercury ratio
c)
Marginal leakage
d)
Insufficient trituration
22.
Resins which soften when heated and set on cooling, are termed
a)
thermoset resins
b)
irreversible resins
c)
thermoplastic resins
d)
etastoMeric resins
23.
Zinc oxide eugenol pastes should not be used as?
a)
a surgical dressing
b)
a permanent filling material
c)
a bite registration paste
d)
an impression material
24.
Creep is associated with?
a)
flow of molten alloy along the sprue
b)
contact angle measurement
c)
marginal breakdcwn of amalgam
d)
expansion of the investment mold
25.
Which of the following hardness tests uses a hardened steel ball indenting tool?
a)
Rockwell hardness test
b)
Vickers hardness test
c)
Brinell hardness test
d)
Knoop hardness test
26.
The property of flow is most important in?
a)
waxes
b)
zinc oxide - eugenol cements
c)
investments
d)
gold alloys
27.
An elastomeric impression will be more accurate if it is?
a)
removed as soon as it sets
b)
removed after 8-10 minuted
c)
allowed to remain in the mouth for a longer time
d)
time in mouth is not critical for accuracy
28.
Methyl methacrylate based denture base resins contain all of the following. Except?
a)
sodium silicate
b)
benzoyl peroxide
c)
dibutyl phthalate
d)
glycol dimethacrylate
29.
When mixing dental stone, if the water-powder ratio is increased, the
a)
compressive strength is increased
b)
surface hardness is increased
c)
setting time is decreased
d)
setting expansion is decreased
30.
What is the name given to the technique in which acrylic resin is softened by heat and introduced<br />into flasks under pressure?
a)
Pressure technique
b)
Injection molding technique
c)
Vacuum molding technique
d)
Compression molding technique
31.
When making an impression, the impression compound should be placed in the patient's mouth<br />at
a)
75°C
b)
37°C
c)
100.4°C
d)
45°C
32.
The phosphate investment clinging to base metal castings is cleaned by?
a)
dipping in cold hydrofluoric acid
b)
grinding with a bur or stone
c)
heating in hydrochloric or sulfuric acid
d)
sand blasting
33.
The high initial solubility of silicate cements is attributed to the?
a)
acid-base nature of the setting reaction
b)
rather long time required for the setting reaction to go to completion
c)
low coefficient of thermal expansion of the cement
d)
high water content of the cement liquid
34.
Inadequate pressure application during flasking.
a)
increase vertical dimension
b)
causes teeth to be shrunken in investmen
c)
cause poor quality of colour
d)
causes fracture of denture
35.
which of the following absorbs maximum amount of water?
a)
microfilled resin
b)
macrofilled resin
c)
Hybrid
d)
small partical composites
36.
Along with polymerisation shrinkage, one of the major disadventages of polymethlymethacrylate as denture base resin are its poor
a)
biological properties
b)
thermal properties
c)
mechanical properties
d)
esthetic
37.
Amalgum achieves 70% of the strength by
a)
2hours
b)
4hours
c)
8hours
d)
16hours
38.
Adequate mixing of mercury is indicated by
a)
dry mix
b)
shiny mix
c)
short mixing time
d)
none
39.
most biocompatible material in oral cavity is
a)
platinum
b)
palladium
c)
Titanium
d)
Gold
40.
Why GIC is best restorative material in children
a)
high strength
b)
Good marginal integrity
c)
it can bound to both enamel and dentin
d)
it has less occlusal wear
41.
Which of the following Is false? An Alginate impression
a)
may exhibit a fluid exudate on the surface as a result of imbibition
b)
will shrink as a result of syneresis
c)
should be at least 3mm thick
d)
will take up water and expand if kept wet
42.
Increased bond strength between resin teeth and resin denture bases, may be obtained by?
a)
using teeth having lesser cross-linking in the ridge lap area
b)
grinding and roughening the ridge lap area of teeth
c)
applying monomer to the necks of teeth for a few minutes before packing resin
d)
all of the above
43.
Polystyrene resins are injected into the mold?
a)
after softening under heat
b)
following liquefaction with organic solvents
c)
in the doughy stage
d)
when the powder-liquid mix is fluid
44.
The plasticizer commonly used in non-aqueous elastomeric impresion materials is?
a)
dibutyl phthalate
b)
colloidal silica
c)
alkyl silicate
d)
silane oligomer
45.
The color stability of self-curing resins is inferior to that of heat-curing resins because of the?
a)
less time required for curing
b)
breakdown of benzoyl peroxide
c)
evaporation of monomer
d)
oxidation of tertiary amine
46.
Typo IV gold casting alloys are used fabricating?
a)
short span bridges
b)
removable partial denture
c)
Inlays
d)
3/4 crowns
47.
Alginate impression materials?
a)
are muco-compressive in comparison to zinc oxide-eugenol
b)
are more dimensionally accurate than reversible hydrocolloids
c)
are hydrophilic
d)
should not be removed from the mouth till at least 15 minutes after gelation
48.
Recommended W/P ratio is lowest for?
a)
Type I plaster
b)
Type II plaster
c)
Type III stone
d)
Type V stone
49.
In dental porcelain, metallic oxides provide?
a)
color and increase strength
b)
color but decrease strength
c)
a refractory skeleton and give color
d)
refractory skeleton and increase strength
50.
The characteristic that refers to the strength or degree of saturation for a particular hue, is termed?
a)
value
b)
chroma
c)
shade
d)
Color
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