dental materials Mcqs
101. Benzoin methyl ether in a polymer indicates that they may be cured in the presence of________________?
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A. Diketone

B. Visible light

C. UV light

D. Infrared light

102. The advantage of unfilled methyl methacrylate is that______________?
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A. It has a low degree of flow

B. It can be finished smoothly

C. Its non-irritation to pulp

D. Its wear resistant is high

103. Which one of the following is the result of applying a load to a wire below its modulus of elasticity on a load deflection diagram ?
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A. Fracture of the wire

B. Spring back

C. Increase in stiffness

D. permanent deformation

104. A material which is a mixture of two different materials and its properties are_____________?
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A. Composite

B. Combined

C. Complex material

D. Compound

105. Which of the following zones is used for melting alloy during casting______________?
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A. Green flame

B. Reducing flame

C. All of the above

D. Oxidizing flame

106. Pickling________________?
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A. Removes surface oxides from gold castings

B. Is accomplished by soaking the casting in baking soda

C. Remove investment from gold casting

D. Causes porosity in gold

107. Which of the following constituents is common in occlusal sealants, bonding agents, composite resins ?
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A. BIS GMA

B. Polymethyl methacrylate

C. Benzoin methyl ether

D. Silica filter

108. Maxwell Voigt Model is to determine________________?
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A. Plastic Behaviour

B. Viscoelastic Behaviour

C. All of the above

D. Elastic Behaviour

109. Liquids which become more rigid as the rate of deformation increases is termed as_____________?
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A. Pseudoplastic

B. Thixotropic

C. Newton

D. Dilatant
110. Composite has_______________?
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A. None

B. Resin

C. Filler

D. Resin & Filler
111. Etching depth after 30 sec for orthodontic bracket with orthophosphoric acid is_________________?
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A. 50 um 110 um

B. 10 um 20 um

C. 3 um 9 um

D. 200 um 250 um

112. The greatest stress which may be produced in a material such that stress is directly proportional to the strain is know as_____________?
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A. The yield strength

B. The proportional limit

C. The elastic limit

D. Modulus of elasticity

113. Ideal requirement of metal ceramic casting____________?
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A. Matching of coefficients of thermal expansion of ceramics and alloy

B. All of the above

C. Bonding between ceramic and alloy

D. Low fusing ceramic and high fusing alloys

114. The function of the coupling agent in a restorative resin is to allow______________?
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A. Bonding between filler crystals

B. Adhesion of resin particles

C. Bonding between tooth and resin

D. Bonding between filler and resin

115. Which of the following provide opacity to composite ?
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A. None of the above

B. TEGDMA

C. BIS-GMA

D. Ti02
116. The simplest alloy is a_______________?
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A. Ternary alloy

B. Solid solution

C. Peritectic allowy

D. Eutectic alloy

117. The particle size in microfilled composites is_____________?
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A. 0.01 to 0.1 microns

B. 0.05 to 0.04mm

C. 0.3 to 0.4mm

D. 0.5 to 1.0 microns

118. Porosity of denture base is due to_______________?
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A. Inadequate pressure

B. Curing at 160F for 9 hrs

C. All of the above

D. Packing at dough stage

119. Which of the following hardness test is a micro hardness test ?
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A. Rockwell

B. Knoop

C. Shore-A

D. Brinnel

120. Dentin conditioner has the following function______________?
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A. Removes smear layer

B. Forms a thin resin layer over exposed collagen fibrils

C. Helps in bonding with composite

D. Increases surface energy of dentin

121. What is the disadvantage of using composites as restorative material ?
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A. Decreased wear resistance

B. None of the above

C. Increased thermal conductivity

D. Decreased thermal conductivity

122. Which of the following absorbs maximum amount of water ?
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A. Macrofilled resin

B. Microfilled resin

C. Hybrid

D. Light cure activated

123. The inlay wax most commonly used for direct technique_____________________?
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A. Type 1

B. Type 3

C. Type 4

D. Type 2

124. No trail closure is necessary with which one of the technique during denture fabrication_____________?
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A. Compression moulding technique

B. Fluid resin technique

C. Light cured technique

D. Injection moulding technique
125. Acrylic (cold cure)______________?
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A. Softens at 100C

B. Melts at 100C

C. Produces heat during polymerization

D. Still requires heat for polymerization

126. KHN of enamel is close to______________?
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A. Pure gold

B. Amalgam

C. Composite

D. Prcelain
127. Brinnel hardness number of a dental gold alloy is directly proportional to its______________?
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A. Tensile strength

B. Modulus of resilience

C. Elongation

D. Modulus of elasticity

128. Use of dimethyl-P-toluidine is indicated for_______________?
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A. Chemical polymerization

B. To inhibit the action of benzoyl peroxide

C. Thermal polymerization of acrylic

D. Retarding the polymerization reaction

129. The forces that hold atoms together are called_____________?
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A. Secondary forces

B. Ionic forces

C. Cohesive forces

D. Primary forces

130. Stress in defined as_______________?
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A. A deformation resulting from an applied load

B. An external force opposing an applied load

C. An applied load or force

D. An internal force opposing an applied load
131. To prevent porosity in self-cure acrylic resin, curing should be carried in______________?
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A. Under vacuum pressure

B. Under tap water

C. Hot water

D. Cold water

132. Flow of a material refers to_______________?
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A. Dimensional change of the material during settings

B. The homogencity of gypsum products

C. Continued change of the material under a given load

D. The consistency of material when mixing

133. The main form of iron carbide found in 18-8 steel________________?
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A. Ferrite

B. Martensite

C. Austenite

D. Pearlite

134. The purity of gold is expressed in________________?
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A. Gram

B. Fineness

C. Carats

D. Percentage

135. Along with polymerisation shrinkage, one of the major disadvantages of polymethyl methacrylate as denture base resin are its poor_____________?
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A. Thermal properties

B. Esthetic properties

C. Biological properties

D. Mechanical properties

136. The commonly used laser for curing composite resin is______________?
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A. Nd:YAG

B. CO2

C. ER:YAG

D. Argon
137. Residual monomer content of chemically activated resins is______________?
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A. 0.2% to 0.5%

B. 0.3% to 0.5%

C. 2% to 5%

D. 2% to 5%
138. Silica sol__________________?
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A. Acts as a retarder in the silica bonded investments

B. Increase the strength and the setting expansion of the phosphate-bonded investment

C. Acts as a refractory in the Silica bonded investments

D. Is applied to the walls of the investment to produce hygroscopic expansion

139. Which of the following inhibitor accelerator system uses light activation composite ?
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A. Diketone-amine

B. Peroxide-amine

C. Organic acid-metal oxide

D. Organic acid-peroxide

140. The most important disadvantage of acrylic denture base is_______________?
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A. Tooth breakage

B. Water absorption

C. Shrinkage

D. porosity

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