dental materials MCQs – Page 9

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

dental materials Mcqs
161. Boiling point of methyl methacrylate________________?
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A. Is at normal room temperature

B. B.P of water

C. Equal of BP of water

D. < B.P of water

162. Back pressure porosity can be avoided by________________?
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A. Using a short and wide sprue

B. Preventing rapid heating the investment in burnout oven

C. Using asbestos linear

D. Placing the sprue at least one quarter inch away form the end of casting ring
163. Which of the following has the highest modulus of elasticity ?
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A. Enamel

B. Dentin

C. Amalgam

D. Composite Resin

164. For adhesion to be present between solid and liquid________________?
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A. Liquid should wet solid surface

B. Should have high contact angle

C. None of the above

D. Mechanical interlocking should be present

165. Insufficient closure of the flasks during packing of denture base resin can result in_____________?
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A. Less polymerization shrinkage

B. Poor colour stability

C. Decrease in vertical dimension

D. Increase in vertical dimension
166. The process wherein two or more chemically different monomers, each with some desirable property, can be combined to yield specific physical properties of a polymer is known as_____________?
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A. Step-growth polymerization

B. Addition polymerization

C. Condensation polymerization

D. Copolymerization
167. Gypsum product having least expansion_____________?
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A. Die stone

B. Model plaster

C. Stone plaster

D. Impression plaster

168. Hydrocolloid material, show all except______________?
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A. Imbibition

B. Recrytallisation

C. Hysterisis

D. Syneresis

169. Setting time of ZOE is best controlled by______________?
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A. Altering ratio of two pastes

B. Adding a drop of eugenol

C. Cooling the glass slab

D. Adding a drop of water

170. Which of the following impression material is rigid ?
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A. Polysulphide rubber

B. Reversible hydrocolloid

C. Alginate

D. Zinc oxide-eugenol
171. Solder and flux used for joining Elgiloy wires are_____________?
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A. Silver solder and fluoride flux

B. Gold solder and fluoride flux

C. Silver Solder and borax flux

D. Gold solder and borax flux

172. The impression for a diagnostic cast of a partial edentulous mouth should be taken in_______________?
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A. Modelling compound

B. Impression wax

C. Hydro-colloid

D. Hydro cal

173. Shape memory in NiTi is because of stress induced form__________________?
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A. Austenite to martensite

B. Ferrite to austenite

C. Austenite to ferrite

D. Martensite to austenite

174. Rapid removal of rubber impression with a single firm motion results in____________________?
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A. Improved adhesion of the impression to the tray

B. Minimal permanent deformation

C. Reduced contamination by saliva

D. Reduced dimensional instability

175. The porosity formed due to simultaneous nucleation of solid grains and gas bubbles at the first moment that metal freezes at the mold walls is called__________?
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A. Pinhole porosity

B. Gas inclusion porosity

C. Subsurface porosity

D. Micro porosity

176. The impression material used to record the prepared areas on abutment teeth is______________?
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A. Low viscosity elastomeric impression material

B. Medium viscosity elastomeric impression material

C. None of the above

D. High viscosity elastomeric impression material

177. Incomplete casting is the result of_____________?
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A. Large reservoir

B. More porous investment in the mould

C. Narrow sprue diameter

D. Hollow sprue pin

178. The most mucostatic impression material is_______________?
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A. Free flowing wax

B. Reversible hydrocolloids

C. Thin mix of plaster of paris

D. Zinc oxide eugenol impression paste

179. Palatal secretions affect the setting of all the impression materials except_______________?
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A. Impression paste

B. Agar-agar

C. Silicone

D. Impression plaster

180. Flux is used during casting to________________?
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A. Remove the oxides formed on the gold alloy

B. Lower the melting point

C. Replace casting wax

D. Speed the burnout process