1) Reduction in the fusion temperature of dental gold casting alloys is caused by presence of______________? a. Platinum b. Copper c. Silver d. Gold
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2) Softening heat treatment of alloy increases_________________? a. Tensile strength b. Proportional limit c. Ductility d. Hardness
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3) The function of a sprue is to_______________? a. Form an opening of molten metal to enter the mold b. Help polish cast restorations c. Eliminate air bubbles on the wax pattern d. Reproduce fine detail
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4) Stabilization of stainless steel is achieved by adding____________? a. Carbon b. Chromium c. Nickel d. Titanium
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5) The yield strength of AUstenite (NiTi alloy) is______________? a. 100 Mpa b. 240 Mpa c. 560 Mpa d. 700 Mpa
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6) A highly polished surface on a metallic dental restoration aids considerably in the prevention of the____________? a. Dimensional change b. Thermal conductivity c. Warpage d. Tarnish and corrosion
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7) Tublulence of molten gold is due to _____________? a. Impurities in gold b. Improper venting c. A and B d. None of the above
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8) In a patient with allergy to costume jewelry, which of the following is contraindicated______________? a. High gold b. Low gold c. Palladium – Ag d. Ni – Cr
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9) Indium in metal alloys_______________? a. Improve bonding b. Harden the metal ceramic Ag-Pd alloy c. Both A and B d. None of the above
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10) Mouth temperature waxes are_______________? a. Iowa wax b. Modeling wax c. Green stick wax d. None of the above
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11) Incomplete casting is the result of_____________? a. More porous investment in the mould b. Narrow sprue diameter c. Hollow sprue pin d. Large reservoir
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12) Glossy smooth margins of a casting are due to_____________? a. Shrinkage of alloy on cooling b. Investment breakdown c. Incomplete wax elimination d. Incomplete gas elimination
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13) Gypsum bonded investment should not be heated over______________? a. 700°C b. 1,300°C c. 1,063°C d. 900°C
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14) Cobalt-Chrominum alloys contains_______________? a. 30% cobalt and 60% chrominum b. 60% cobalt and 30% chrominum c. 1% palladium d. 20% gold
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15) The most commonly used Titanium alloy for dental and medical purposes is________________? a. Ti 6Al 4V b. Ti 5Al 4V c. Ti 5Al 5V d. Ti 6Al 6V
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16) Wax pattern is ideally invested immediately to decrease the dimensional changes caused by_______________? a. Decrease flow b. Continuous expansion c. Relaxation of the internal stresses d. Water loss
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17) The maximum carbon content of steel used in dentistry is__________________? a. 19% b. 2% c. 1.7% d. 4%
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18) Flux is used during casting to________________? a. Remove the oxides formed on the gold alloy b. Lower the melting point c. Replace casting wax d. Speed the burnout process
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19) Resistance to corrosion in a cobalt-chrome casting is due to presence of_______________? a. High quality iron b. Chrome c. Cobalt d. Nickel
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20) Which is the use of boxing an impression______________? a. Ease of construction of denture b. Preserving the sulci c. Ease of pouring an impression d. All of the above
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21) Gap between true end of casting ring and wax pattern should be______________? a. ¼ inch b. ½ inch c. 3/8 inch d. one inch
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22) Addition of large amounts of platinum to a casting gold alloy will________________? a. Decrease its strength and ability to be hardened b. Decrease its tarnish resistance c. Increase its fusion temperature d. Redden the alloy
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23) All of the following statements about cast cobalt alloy are true EXCEPT_____________? a. They have a modulus of elasticity twice that of gold alloys b. They are more rigid than gold alloys c. They have higher ductility than gold alloys d. They have a lower proportional limit than gold alloys
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24) 4th state of matter is______________? a. Solid b. Liquid c. Gas d. Colloid
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25) All of the following statements about an alginate impression are EXCEPT________________? a. It should be rapidly displaced from the mouth b. It may exhibit fluid exudates on the surface as a result of imbibition of water c. It will take up water and expand if kept wet d. It will shrink as a result of syneresis
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26) Type I and Type II zinc oxide impression paste differ with respect to_______________? a. Their use b. Their hardness after setting c. Water content d. Eugenol content
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27) The term given to the phenomenon of moisture absorption by an alginate impression in________________? a. Imbibition b. Syneresis c. Hysteresis d. Gelation
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28) The impression with the least dimensional change upon disinfection is_______________? a. Addition poly silicone b. Agar-agar c. Polysulphide d. Polyether
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29) Palladium is added to polyvinyl siloxane to_____________? a. Act as a scavenger b. Helps as surfactant c. Acts as plasticizer d. Acts as a catalyst
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30) Immediate pouring of impressions is most critical in_____________? a. Condensation polysillicon b. Addition Polysilicon c. Polyether d. A and B
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31) The impression material used to record the prepared areas on abutment teeth is______________? a. High viscosity elastomeric impression material b. Medium viscosity elastomeric impression material c. Low viscosity elastomeric impression material d. None of the above
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32) Alginate impression material is________________? a. Non-elastic impression material b. Thermoplastic impression material c. More mucostatic than ZOE d. Less mucostatic than ZOE
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33) Syringe material is______________? a. High viscosity elastomer b. Medium viscosity elastomer c. Medium & low viscosity elastomer d. Low viscosity elastomer
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34) The impression for a diagnostic cast of a partial edentulous mouth should be taken in_______________? a. Impression wax b. Modelling compound c. Hydro-colloid d. Hydro cal
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35) Agar impression materials differ from alginate impression materials in that the former sets by_______________? a. Mechanical action of saliva b. Physical change c. Evolution d. Chemical change
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36) Which material undergoes hysteresis ? a. Irreversible hydrocolloid b. Reversible hydrocolloid c. Impression plaster d. Metallic oxide paste
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37) The setting time of irreversible hydrocolloids can be decreased by_____________? a. Raising the temperature of water used for maxing b. Using excess water for maxing c. Lowering the temperature of water used for mixing d. None of the above
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38) Rubber base impressions are poured immediately as they_______________? a. Continue to polymerize b. Become elastic c. Show imbibition and syneresis d. Show gelation
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39) The most mucostatic impression material is_______________? a. Thin mix of plaster of paris b. Zinc oxide eugenol impression paste c. Free flowing wax d. Reversible hydrocolloids
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40) The best way to remove a hydrocolloid impression from the patient’s mouth is____________? a. Slight rocking of the impression to disengage it from the undercut b. Wetting the periphery of the impression with moist cotton to break the peripheral seal c. Sudden jerking of the impression to prevent tearing d. Supporting the impression along with the tray to prevent disengaging of the tray alone
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