Biomaterial Test 0% 5 votes, 5 avg 529 You will have 60 minutes to complete all the questions. After the timer reaches 60 minutes, the exam will end and be saved automatically. Good luck! *Fingers crossed* The timer has been reached. The exam has now been terminated and saved. Biomaterial Test 1 / 60 Which of the following is a measure of resistance to fracture ?: a. Brittleness b. Springiness c. Toughness d. Hardness 2 / 60 Ideally, the set amalgam should do which of the following ? a. Have little dimensional change b. Expand greatly to provide marginal seal against the tooth c. Properties of amalgam d. Shrink significantly to provide space for correction products to seal the margins 3 / 60 Full denture bases are usually made from which of the following materials ? a. Composite restorative resins b. Acrylic resin c. Gold alloys d. Ceramic 4 / 60 Stearic acid in impression compound 😕 a. Reduces brittleness b. Reduces flow c. Reduces plasticity d. Increase setting time 5 / 60 Proconditioning before GIC restoration is done in order to 😕 a. Provide more strenght b. Facilitate mechanical bonding c. Remove smear layer d. Create tags 6 / 60 The temperature at which a solid changes into liquid is called 😕 a. Fusion temperature b. Specific temperature c. Latent heat d. Temperature of vaporization 7 / 60 Contamination of zinc-containing amalgam by moisture during triturating or condensation : a. Has no appreciable effect on properties except to the susceptibility to tarnish b. Results in a sharp decrease in flow c. Results in a marked expansion d. Increases the setting time 8 / 60 Which of the following phases in dental amalgam restoration has the best mechanical properties ? a. Cu-Sn b. Ag-Hg c. Ag-Sn d. Sn-Hg 9 / 60 Commonly used filler in composite is 😕 a. Quartz b. Colloidal silica c. Glass d. Aluminum 10 / 60 For proper wetting, contact angle should be ideally 😕 a. 00 b. 450 c. 900 d. 600 11 / 60 Color stability of cold-cured resins is inferior to that of heat cured resins due to 😕 a. Variation in the molecular weight of the resin (low mol wt) b. Decreased polymerization of the resin c. Increased solubility of the resin d. Subsequent oxidation of the tertiary amine 12 / 60 Minimal thickness of base for adequate thermal insulation is 😕 a. 0.5 mm b. 0.75 mm c. 2 mm d. 1 mm 13 / 60 The most commonly used implant type presently is 😕 a. Transosteal implant b. Subperiosteal c. Endosseous d. Intramucosal implant 14 / 60 Which of the following statements about adhesion of composite restorations to tooth structure are true ? a. The bonding agent forms a hybrid layer with enamel. b. The bonding agent forms a micromechanical bond with enamel but a chemical bond with dentin. c. Most bonding agent bond more effectively to a dry tooth surface. d. Bonding is achieved to enamel by application of an acid etchant followed by application of a bonding agent and then the composites resin. 15 / 60 The restorative material used to restore a small portion of an anterior tooth should have which of the following properties ? a. Amalgam b. Ease of casting c. High strength d. Esthetics 16 / 60 Which of the following waxes is obtained from distillation of petroleum ? a. Carnauba and candellia b. Montan and Japan coco c. Paraffin and microcrystalline wax d. Spermitic and bees wax 17 / 60 The gelation temperature of agar hydrocolloid impression material should be 😕 a. 45-600C b. 37-450C c. 100C higher than mouth temperature d. Far below the oral temperature 18 / 60 In the cavities which are more than 2mm deep a light-cured restoration is 😕 a. Cured for longer period b. Restoration should be build in increments c. Fifth generation bonding agent should be applied d. Not indicated 19 / 60 Minimum light exposure time for composite resins should be 😕 a. 20 sec b. 5 sec c. 10 sec d. 40 sec 20 / 60 Inorganic phase in a composite matrix 😕 a. Increases the polymerization shrinkage b. Increases the mechanical strength c. Increases coefficient of thermal expansion d. Decreases the mechanical strength 21 / 60 Once amalgamation has occurred, which of the following is true of mercury ? a. Can form at the surface of amalgam restorations if heated to 0° C b. Composite restorative resins c. Has the toxic properties of unreacted mercury d. Is combined primarily with silver 22 / 60 The light-cured restorative resins have advantages over chemically activated restorative resins as 😕 a. It is more sensitive to oxygen inhibitors b. It has not more working time available c. It has more working time available d. It takes more time for curing 23 / 60 Conventional dental amalgam alloy contains 😕 a. Silver, mercury, copper and zinc b. Silver, tin, palladium and zinc c. Silver, tin, copper and zinc d. Silver, mercury, copper and mercury 24 / 60 A potentially toxic element in base metal alloys is 😕 a. Molybdenum b. Boron c. Magnesium d. Beryllium 25 / 60 Nickel sensitivity in the general population is 😕 a. 1% in the overall population b. 3% for men c. 3% for women d. 11% for women 26 / 60 One of the following statements which one is incorrect regarding polyether : a. The main chain of polyether consists of copolymer of ethylene oxide and tetrahydrofuran b. The main chain consists of copolymer of methylene oxide and tetrahydrofuran c. Aromatic sulfonate ester acts as a cross linking agent d. The base paste consists of polyether polymer 27 / 60 The strain at which the plastic strain develops may be represented by 😕 a. Elastic limit, modulus of elasticity, tensile strength b. Toughness, rigidity, resilience c. Elastic limit, yield strength, proportional limit d. Yield strength, tensile strength, toughness 28 / 60 Which one of the following is not a criterion for a failed high-copper dental amalgam restorations ? a. Marginal ditching along occlusal margins b. Micrographs of alloys particles. c. Creep of the restoration out of the cavity preparation in proximal areas d. Wear facets along the occlusal contach areas 29 / 60 Which of the following polymer systems are used for the organic matrix in composites ? a. Poly (methyl methacrylate) b. Pheyl methacrylate c. Bisphenol A-glycidyl methacrylate (Bis-GMA) d. Polystyrene 30 / 60 For luting purpose, the film thickness should be 😕 a. minimum 50 μm b. ideally 100 μm c. up to 75 μm d. 25 μm or less 31 / 60 The fluoride release from glass ionomer cement is 😕 a. 0.75 mg during the first week b. 0.075 mg during the first month c. 0.0005 mg during the first month d. 0.005 mg during the first week 32 / 60 Property which distinguishes composites from filled acrylic resins 😕 a. Adhesive bonding between matrix and filler b. Bonding between coupling agent and tooth structure c. Bonding with tooth structure d. Bonding between coupling agent and filler 33 / 60 One of the disadvantages of using quartz as filler in restorative resin is 😕 a. It cannot be reduced to the size of microparticle composite b. It cannot be polished c. It has low affinity for resin matrix d. It cause abrasion and wearing of opposing tooth surface 34 / 60 Which of the following is a measure of resistance to fracture ? a. Toughness b. Brittleness c. Springiness d. Hardness 35 / 60 Greening effect of porcelain is due to 😕 a. Golde b. Silver c. Platinum d. Palladium 36 / 60 Which of the following properties are higher for microhybrid composites than for microfilled composites ? a. Modulus of elasticity b. Polymerization shrinkage c. Thermal expansion d. Water sorption 37 / 60 Oil of clove is sometimes used in preference to eugenal in ZOE paste because : a. To increase setting time b. It increases mixing property of paste and therefore improves impression recorded c. Reduces burning sensation of paste d. Has a better reaction with zinc oxide 38 / 60 Dental personnel can do which one of the following to limit their exposure to mercury ? a. Avoid polishing amalgams b. Sterilize amalgam scrap c. Avoid touching freshly mixed amalgam d. Vacuum up a spill immediately 39 / 60 The main use of zinc oxide eugenol cement is 😕 a. Indirect pulp capping agent b. Permanent restoration c. Base d. Temporary restoration 40 / 60 Cobalt-chromium alloy is mostly used for the construction of 😕 a. Transosteal frames b. Subperiosteal c. Endosseus implants d. Intramucosal frames 41 / 60 Elgiloy arch wire is 😕 a. Gold alloy b. β-titanium arch wire c. Optical fiber arch wire d. Cobalt-chromium-nickel alloy 42 / 60 The most commonly employed alloy combination for use in implants is 😕 a. Titanium-platinum-aluminum alloy b. Platinum-aluminum-vanadium alloy c. Titanium-molybdenum-vanadium alloy d. Titanium-aluminum-vanadium alloy 43 / 60 Zinc oxide eugenal impression should be removed from oral cavity : a. When the material is glossy b. When it can be easily indented by a blunt instrument c. When the material cannot be intended by a blunt instrument d. Exactly after four minutes after kneading 44 / 60 Which of the following elastomers is suited for multiple cast pouring 😕 a. Polyether b. Condensation silicone c. Addition silicone d. Polysulfide 45 / 60 Polyether is different from other elastomers in the following aspects 😕 a. High stiffiness b. Low stiffness c. Can not be used as light cure material d. Hydropholic in nature 46 / 60 Wrought metal 😕 a. Can be formed by pouring molten metal into a mold b. Can be formed by working on a cast metal c. Cannot be rendered corrosion resistant d. Cannot be heat treated 47 / 60 The light from the visible light curing unit can cause 😕 a. Iritis b. Cataract c. Corneal ulceration d. Retinal damage 48 / 60 Higher mercury left in an amalgam leads to which of the following ? a. Higher creep b. Higher strength c. High corrosion d. Low corrosion 49 / 60 Which of the following initiator-accelerator systems is needed for a light-activated composite? a. Diketone-amine b. Organic acid-metal ion c. Peroxide-amine d. Organic acid-peroxide 50 / 60 The maximum warpage of acrylic denture occurs during 😕 a. Packing b. Deflasking c. Polishing d. Curing 51 / 60 Passiveness of chrome cobalt alloys is due to formation of 😕 a. Chromium carbide b. Ferric oxide c. Chromium oxide d. Cobalt oxide 52 / 60 Ideal method firing of porcelain is by using 😕 a. Shorter firing at higher temperatures b. Longer firing at low temperatures c. Longer firing at high temperatures d. Shorter firing at low temperatures 53 / 60 Most commonly used pit and fissure sealant is 😕 a. Bis-GMA resin b. Polyurethane c. Filled acrylic d. Unfilled acrylic 54 / 60 Pick out the incorrect statement regarding alginate impressions 😕 a. Will take up water and expand if kept wet b. Will be shrink as a result of syneresis c. May exhibit a fluid exudates on the surface as a result of imbibitions d. Is an irreversible hydrocolloid impression material 55 / 60 Hydrocolloid impression should be removed from the mouth with a sharp jerk because 😕 a. It decreases the time for syneresis to occur b. It is the easiest method of removal c. Faster rate of removal increases the yield strength d. The brush heap structure of a gel responds more favorably to a sudden force 56 / 60 Which of the following statements about laboratory composites are true ? a. Restorations prepared from laboratory composites typically are cemented with zinc phosphate cement. b. Fiber reinforcement increases their strength but decrease their rigidity. c. Curing using light, heat, and pressure increase the wear resistance. d. Bridge prepared from laboratory composites require a metal substructure. 57 / 60 Which of these statements apply to the filler particles of composites ? a. Microfilled b. Microhybrid composites contain as much as 84% filler by weight. c. Microfilled composites contain more filler than all-purpose composites. d. All are correct 58 / 60 Which of the following waxes used to align of castings before soldering ? a. Base plate wax b. Utility wax c. Carding wax d. Sticky wax 59 / 60 Alginate impression material deteriorates rapidly at 😕 a. Elevated temperature b. Temperature does not cause any change in shelf-life c. Low temperature d. Normal room temperature 60 / 60 Impression compound is characterized by 😕 a. Crystalline in nature with high thermal conductivity b. Amorphous in nature with high thermal conductivity c. Amorphous in nature with low thermal conductivity d. Crystalline in nature with definite melting point Your score isThe average score is 85% Facebook 0% Restart quiz Any comments? Send feedback
