dental materials MCQs – Page 8

Practise focused dental materials questions with marked answers for exam preparation and subject revision.

dental materials Mcqs
141. Cold cure acrylic expand in water by___________?
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A. 1% by volume 0.23% by weight

B. None of the above

C. 0.1% by volume 0.23% by weight

D. 10% by volume 0.23% by weight

142. In processing methyl methacrylate, the resin may show porosity if the flask is placed too soon porosity most likely occur_____________?
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A. On the denture surface

B. Throughout the denture

C. In the thickest part

D. Near the borders

143. Coefficient of thermal expansion of which of following is most similar to that of tooth ?
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A. Gold foil

B. Acrylic resin

C. Silicate cement

D. Gold inlay

144. Setting expansion is advantageous in__________________?
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A. Investment

B. Dies

C. Casts

D. Models

145. Compressive stress is computed by dividing the external force by the_______________?
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A. Length of the test specimen beneath the force

B. Strain of the test specimen per unit length

C. Area of the test specimen upon which the weight rests

D. Elasticity of the test specimen in strain

146. VLC resins are also called as______________?
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A. Microwave-activated resins

B. Heat activated resins

C. Light activated resins

D. Tertiary amine-activated resins

147. If curing occurs at temperature more than 100C porosity results in which area of denture______________?
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A. Thin area of flanges

B. Porosity is uniformly distributed

C. Thin Palatal area

D. Hard thick central area
148. Brazilian test is used to determine the ultimates tensile strength of_________________?
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A. Malleable materials

B. Ductile materials

C. Brittle materials

D. Flexible materials

149. The Knoop Hardness Number of Microfilled composite Restorative material ranges from____________?
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A. 40 48 KHN

B. 25 35 KHN

C. 50 60 KHN

D. 15 20 KHN

150. Deformation that is recovered upon removal of an externally applied force or pressure is known as_____________?
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A. Flexural strain

B. Plastic strain

C. Youngs modulus

D. Elastic strain
151. The chemical used to etch enamel is_______________?
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A. Eugenol

B. Zinc oxide

C. Phosphoric acid

D. Methyl methacrylate

152. Cross linking in denture base resin is contributed by_____________?
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A. Glycol dimetharylate

B. Benzoyl peroxide

C. N-para toluidine

D. Methyl methacrylate

153. A restorative material which has a high proportional limit, compared with one with a lower proportional limit would have________________?
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A. More resistance to permanent deformation

B. Greater toughness

C. A higher modulus of elasticity

D. A higher modulus of elasticity

E. Greater ductility

154. Which of the following is NOT true of polymethyl methacrylate ?
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A. Knoop hardness number 18 to 20

B. Density of 1.13 g/cm3

C. Tensile strength of 60 MPa

D. Modulus of elasticity of 3.4 GPa
155. In self-cure acrylic resin, activator is_____________?
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A. Benzoyl peroxide

B. Quaternary ammonium compound

C. Toluidine

D. Tertiary amine
156. About polymerization shrinkage of composite all are true, except______________?
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A. Acid etching and priming will decrease polymerization shrinkage

B. Polymerization shrinkage is greater if bonded surface area is lesser than unbounded surface area

C. Microleakage can occur because of polymerization shrinkage

D. Polymerization shrinkage is high if within the enamel margins

157. A material behaves in certain ways above and below the proportional limit on a stress strin curve, which of the following is correct______________?
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A. Either A or B

B. Above the proportional limit a material function in a plastic manner, while below the proportional limit it behaves as an elastic

C. Neither A or B

D. Above the proportional limit a material functions in an elastic manner, while below the proportional limit it behaves as an plastic

158. When solid gets wet completely contact angle is______________?
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A. 0 90

B. >90

C. 0

D. 90

159. Ultimate tensile strength refers to_________________?
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A. Stress after rupture

B. Longitudinal compressive strength

C. Stress before rupture

D. Horizontal compressive strength

160. The modulus of elasticity is defined as_______________?
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A. The strain at the proportional limit

B. The stress at the proportional limit

C. None of the above

D. The stress/strain ratio within the proportional limit