Quiz
Biomaterials
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Questions in this quiz (90)
1Which mixing method is not used for dental materials?
- APowder and liquid precapsulated and mixed in a triturator
- BPowder and liquid mixed on a mixing pad
- CTwo liquids agitated together using a vibration
- DPowder and water mixed together with a spatula in a mixing bowl
- ETwo liquids mixed through a mixing nozzle
2What of the following is the mixing time?
- AElapsed time from the beginning of mixing until the beginning of setting
- BElapsed time from the beginning of the working interval until the end of the setting interval
- CThe setting interval
- DThe time required by the operator to handle and place a dental material
- EElapsed time from the start of mixing until the end of mixing
3Which of the following materials does not set by polymerization?
- AHybrid glass ionomer cement
- BDental stone
- CPolyvinyl siloxane impression material
- DPolysulfide impression material
- EPackable dental composite
4Why is the linear coefficient of thermal expansion important for restorative materials?
- AIt predicts the loss in strength of a restorative material as the temperature increases.
- BIt indicates the insulating characteristics of a restorative material.
- CIt indicates the resistance to thermal degradation of a material
- DIt indicates the amount of expansion/contraction on polymerization
- EIt predicts the mismatch in expansion/contraction at the interface of restorative materials.
5Which of the following materials involves imbibition problems?
- ADental sealant
- BDental composite
- CDental cement
- DAlginate impression material
- EGold restorations
6Which of the following is a rapid thermal conductor?
- ADentin
- BDental Amalgam
- CDental Composite
- DZirconia all ceramic inlays
- EDental Enamel
7Which of the following undergoes crevice corrosion under plaque that causes pitting?
- AStainless steel restorations
- BCast-gold restorations
- CPFM restorations
- DNiCr partial-denture alloys
- EAll of the above
8Which of the following is best for pulpal insulation?
- A1 mm of remaining dentin thickness
- B3 mm of composite restoration
- C5 mm of dental amalgam restoration
- DSurface sealant over restoration
- E1 mm of calcium hydroxide liner
9Which one of the following terms is not important for color matching?
- AAmbient lighting conditions
- BSurface gloss
- CTranslucency
- DInitiation
- EHue and chroma
10Which one of the following is not associated with electrochemical corrosion events?
- ACrevices
- BStress
- CPassivation
- DRadiopacity
- EPlaque
11Engineering stress is computed as
- Adeformation divided by the volume of the object.
- Bmodulus multiplied by the plastic deformation.
- Cdifference between the total strain and plastic strain
- Ddeformation divided by the original length
- Eapplied load divided by original cross-sectional area
12Engineering strain is computed as
- Aarea under the stress-strain curve.
- Bload at yield divided by elastic deformation.
- Capplied load divided by the total elastic deformation
- Ddeformation divided by the original length of the object
- Echange between the initial and final strain divided by the time
13What is another name for a material's stiffness?
- AElastic limit
- BToughness
- CFatigue resistance
- DBrittleness
- EModulus
14Loading of a restoration beyond the material's elastic limit causes
- Aonly elastic deformation
- Bfatigue fracture
- Celastic and plastic deformation
- Dstress relaxation
- Eonly plastic deformation
15At what point does loading produce both plastic and elastic strain at the same time?
- AToughness
- BModulus
- CEndurance limit
- DElastic limit
- EFracture
16What is the Mohs hardness value for enamel?
- A2
- B3-4
- C5-6
- D7
- E9
17Which phase in dental amalgam restorations is most likely to corrode?
- AAg-Sn
- BAg-Sn-Cu
- CSn-Hg
- DCu-Sn
- EAg-Hg
18Which phase in dental amalgam is strongest?
- AAg-Cu
- BCu-Sn
- CAg-Hg
- DAg-Sn
- ESn-Hg
19Which method for amalgam is recommended to minimize mercury vapor escape during mixing?
- AFriction-fit capsule
- BPrecapsulated alloy and mercury
- CCovered mixing arm on the triturator
- DNone of the above
- EMortar and pestle
20High-copper dental amalgam alloys involve what range of copper in their composition?
- A12% to 30%
- B6% to 12%
- C1% to 5%
- D0.5% to 1%
- E0.1% to 0.5%
21What is the major advantage of high-copper over low-copper dental amalgam restorations?
- ALower coefficient of thermal expansion
- BGreater polishability
- CLower corrosion tendency
- DLower thermal conductivity
- EBetter compressive strength
22What is the OSHA limit for exposure to mercury vapor in air during a 40-hour workweek?
- A50 μg/m3
- B42 μg/m3
- C31 μg/m3
- D20 μg/m3
- E15 μg/m3
23What is the melting temperature of the Ag-Hg matrix phase in a set dental amalgam restoration?
- A167°C
- B157°C
- C147°C
- D137°C
- E127°C
24What is a major problem associated with polishing a dental amalgam?
- ABurnishing of surface corrosion products into the amalgam
- BProduction of grayish color
- CLocalized melting of the amalgam with mercury smearing
- DSmearing amalgam onto enamel to cause staining
- ECreation of marginal ditching
25. What is the incidence of hypersensitivity to mercury from dental amalgam restorations in the general population?
- A1 per 2000 patients
- B1 per 50,000 patients
- C1 per 3 million patients
- D1 per 5 million patients
- E1 per 100 million patients
26 What is the principal reason for the shift away from dental amalgam use?
- AEnvironmental concerns about mercury
- BMuch improved mechanical properties of other materials
- CPatient hypersensitivity problems to mercury released from amalgams
- DLower cost of procedures for alternative restorative materials
- EToxicity of mercury to office personnel
27What is the main reason for failure of a high-copper dental amalgam restoration?
- AOcclusal marginal ditching
- BCreep
- CWear facets
- DInterproximal Caries
- EBlack or Green Tarnish
28Which restorative material is most often substituted for dental amalgam in posterior restoration applications?
- ADental composite
- BHybrid glass ionomer
- CDirect gold
- DART restorations
- EAll-ceramic
29Which of the following is true about pit-and-fissure sealants?
- ASealants should be filled to improve their mechanical properties.
- BTinted sealants are more useful than colorless ones.
- CSealant inspection is unnecessary after 2 years.
- DPartial sealing of pits and fissures is better than no sealing at all.
- EUncured sealant along air-exposed surfaces will finish curing in 24
30Which event does not alter the esthetics of existing composite restorations?
- AExtensive tea exposure
- BAPF application
- CTobacco use
- DGum chewing
- EWhitening techniques
31Which of the following is likely to be deceptive in appearance in a radiograph?
- ADental composite restoration
- BDental sealants
- CTemporary restorations
- DGlass ionomer restorations
- EInfiltrants
32What is the most appropriate way to manage long-term wear or discoloration of posterior dental composite restoration surfaces?
- AReplace the composite with a dental amalgam
- BRepair the worn areas with resin-modified glass ionomer
- CResurface the old composite with new composite.
- DReplace the restoration with a new, high-strength ceramic.
- EAdjust the occlusion of the opponent tooth
33Which procedure does not require phosphoric acid etching?
- ACeramic orthodontic bracket attachment
- BTotal-etch dentin bonding procedure
- CSelf-etch dentin bonding procedure
- DAmalgam bonding procedure
- EDental sealant
34Which of the following is true about the dentin smear layer?
- AComposed mostly of collagen and water
- BDissolved by acid etching during bonding procedures
- CEasily removed with air/water spray
- DEffectively seals dentin
- E50- to 100-μm-thick debris layer
35What is required to produce good bond strength to dentin?
- ADrying of dentin
- BPreapplication of chlorhexidine
- CPost-curing materials with visible light
- DHybrid layer formation
- ELong conditioning (etching) times
36How do self-etching bonding systems work?
- AAcidic monomers replace need for phosphoric acid etching.
- BNew monomers chemically adhere to hydroxyapatite.
- CPhosphoric acid is mixed with other components of the bonding system.
- DChemical bonding to collagen replaces need for micromechanical bonding.
- EWetting agent helps adaptation and replaces need for micromechanical bonding
37What products most likely contain water-miscible acrylic monomers?
- AAcidulated phosphate fluoride (APF)
- BPit-and-fissure sealants
- CDentin primers
- DResin surface sealers
- EPolishing pastes
38Which component of the dentin bonding system is most likely to cause skin sensitization in dental personnel?
- AHEMA
- BEthanol
- CUDMA
- DBis-GMA
- EPhosphoric acid
39What is the shorthand representation for a self-etching primer adhesive?
- AE+PB
- BEP+B
- CEPB
- DE
- EE+P+B
40Which of the following restorations requires surface protection with petroleum jelly during APF applications?
- AAmalgams
- BDental sealants
- CCast gold
- DOrthodontic wire
- EPorcelain ceramics
41Which of the following constituents may have a palliative action on the dental pulp?
- ACalcium hydroxide
- BBis-GMA
- C4-META
- DEugenol
- EHEMA
42What is the primary filler component composite cement?
- APotassium oxide
- BSilicon oxide
- CZinc oxide
- DCalcium oxide
- EAluminum oxide
43Which of the following dental cements does not include polymer as part of the matrix?
- APolycarboxylate cement
- BGlass ionomer cement
- CResin-modified glass ionomer cement
- DComposite cement
- EZinc oxide-eugenol (ZOE) cement
44. What ions on tooth structure permit glass ionomer chemical adhesion?
- ACalcium ions
- BFluoride ions
- CCarboxylic acid ions
- DHydrogen ions
- EAluminum ions
45Which of the following materials does not release fluoride?
- AResin-modified glass ionomer
- BART restorations
- CProvisional restorations
- DCompomer
- ETraditional glass ionomer
46Which of the following choices MOST resembles a compomer?
- AGlass ionomer
- BZinc phosphate cement
- CPolycarboxylate
- DGiomer
- EComposite
47The fluoride release from glass ionomers follows what pattern?
- ARapid decrease to low level after 24 hours
- BRapid decrease over 7 to 14 days
- CSome decrease after 30 days
- DSome decrease after 6 months
- ESome decrease after 1 year
48 What is the effectiveness of recharging glass ionomer restorations?
- ADoes not work
- BIncreases fluoride release for a few days
- CIncreases fluoride release for a few months
- DIncreases fluoride release for 1 to 2 years
- EPermanently reestablished fluoride release from the material
49Which of the following applications typically involves an ART material?
- AClass II restorations
- BClass IV restorations in permanent teeth
- CLiner under composite restorations
- DTemporary restorations
- EClass III esthetic restorations
50Which impression material is a hydrogel?
- AZOE
- BPolysulfide
- CPolyether
- DPolyvinyl siloxane
- EAlginate
51 Which of the following features does not apply to polyvinyl siloxane impression material?
- ALow shrinkage on setting
- BDimensionally stable
- CAccurate
- DContains no filler
- EShould not be poured immediately
52Which application typically requires the strongest gypsum material?
- AMaster cast
- BRepairing casts
- CRemovable die
- DDenture fabrication
- Eorthodontic model
53What is the chemical composition of set gypsum products?
- ACalcium sulfate dihydrate
- BCalcium sulfate monohydrate
- CCalcium sulfate unhydrated
- DCalcium sulfate hemihydrate
- ECalcium sulfate trihydrate
54What is the chemical composition of gypsum powder that is to be mixed with water to form models?
- ACalcium chloride
- BCalcium sulfate hemihydrate
- CCalcium carbonate
- DCalcium fluoride
- ECalcium phosphate
55How much "water of reaction" is required for the actual setting of 100 g of calcium sulfate hemihydrate powder?
- A12 mL
- B18 mL
- C24ml
- D32ml
- E50ml
56What is the major difference between plaster and stone powders?
- Acolor
- Bcrystal structure
- Cpowder particle packing
- Dsterilization techniques
- Ehydration state
57Why does diestone require less water for mixing than plaster?
- ADiestone undergoes a different reaction than stone.
- BDiestone powder particles are less porous and imbibe less water.
- CDiestone chemical reaction generates less heat and requires less cooling.
- D. Diestone contaminants are minimized by adding less water.
- E. Diestone powder particles pack more efficiently.
58Why should molten wax be applied slowly and in thin layers onto dies?
- ATo minimize porosity
- B. To promote wetting onto the dies
- CTo avoid distortion from thermal contraction during wax cooling
- DTo avoid sag due to wax's low modulus
- ETo avoid water absorption
59What is the role of paraffin in most dental waxes?
- AIncrease hardness
- BIncrease thermal stability
- CAct as main low-melting component
- DReduce thermal expansion
- Eincrease tackiness
60What is the main goal in the design of dental inlay waxes?
- ALow cost
- BLow melting temperature
- CComplete pyrolysis on heating to CO2 and H2O
- DLow coefficient of thermal expansion
- EHigh hardness
61What are the primary constituents of an investment material?
- ATwo fillers and a binder
- BTwo liquid binders
- CMatrix, filler, and modifier
- DTwo filled pastes that are mixed
- EBinder and accelerator
62What is the principal advantage of phosphate-bonded investment (PBI) over gypsum-bonded investment (GBI)?
- AStronger
- Bless setting expansion
- Cfaster reacting
- Dlower cost
- Emore stability at higher temperatures
63What is the karatage of an alloy that is 80% Au by weight?
- A10 karat
- B13 karat
- C16 karat
- D19 karat
- E22 karat
64. In high-gold casting alloys, which element produces a temporary protective oxide on the molten alloy surface during the casting process?
- AZn
- BAg
- CCu
- DPd
- EAu
65 In high-gold casting alloys, which element is primarily responsible for hardness?
- ACu
- BZn
- CAu
- DPd
- EAg
66What element is responsible for producing the corrosion resistance of stainless steel instruments?
- AFe
- BC
- CCo
- DNi
- ECr
67What level of chromium is required in steel alloys to produce effective passivation?
- A10% to 14%
- B14% to 18%
- C18% to 28%
- D28% to 40%
- E>40%
68Which one of the following terms is not specifically related to soldering?
- ABrazing
- BJoining
- C600-650 fine
- Dprecious metal content
- Efiller metal
69Which application does not use gold alloys?
- ACast alloy bridge
- BPartial-denture framework
- CCast post and core
- DImplant
- ECast alloy crown
70Which of the following dental materials cannot cause nickel sensitivity?
- AStainless steel crowns
- BSome PFM alloys
- C. Some partial-denture framework alloys
- DDental amalgam
- Esome orthodontic wires
71What is the approximate incidence of nickel sensitivity for men?
- A6%
- B12%
- C18%
- D24%
- E30%
72What events contribute to a relatively high nickel sensitivity level in women?
- AContact dermatitis from nickel-based jewelry
- BGreater contact with stainless steel
- CGenetic differences
- DLess protective skin and hair during contact
- EGreater contact with metal coinage
73What are the three principal components of dental porcelains?
- AAlumina, zinc oxide, and calcium fluoride
- BAlumina, potassium oxide, and calcium oxide
- CCalcium oxide, magnesium oxide, and chromium oxide
- DSilica, alumina, and potassium oxide
- ESilica, calcium oxide, and alumina
74What component of dental porcelain contributes primarily to esthetics?
- ASilica
- BPotassium oxide
- CChromium oxide
- DTitanium oxide
- EAlumina
75What component is involved with very-high-strength dental ceramics?
- ASilicon carbide
- BPotassium oxide
- CChromium oxide
- DZirconia
- Esilica
76Which statement is not true about feldspathic porcelain?
- ARelatively low coefficient of thermal expansion
- BDuctile
- CUsed to veneer most dental porcelains
- DHigh hardness
- EExcellent translucency
77Which one of the following dental materials is not a ceramic?
- Asilicon carbide
- BCorundum
- CHydroxyapatite
- DZirconium
- ETitanium dioxide
78Which is true of all traditional dental cements?
- AEndothermic reactions
- BAcid-base reactions
- CGood esthetics
- DHigh strength
- EPrecapsulated
79Which of the following dental cement compositions requires staged additions of powder to the liquid during mixing on a chilled glass slab to control the reaction?
- APolycarboxylate cement
- BResin-modified glass ionomer cement
- CZinc phosphate cement
- DUniversal cement
- ECompomer cement
80What is the primary monomer involved in denture base fabrication?
- AEMA
- BBis-GMA
- CMMA
- DUDM
- EHEMA
81. Why are acrylic resin teeth popular for denture fabrication?
- Aexcellent wear resistance
- BEase of cleaning
- CEasily bonded to denture base
- DLight weight
- EBest esthetics
82What is the major problem for tissue conditioners over the first few days?
- ADiscoloration
- BBad taste
- Closs of bonding
- Dincreased hardness
- Efungal growth
83Mouth protectors should be cleaned with
- Aultrasonic agitation in baking soda solutions.
- Bdilute chlorine bleach in water.
- Cdenture-cleaning solutions.
- Dcool soap-and-water solutions.
- Edilute chlorhexidine solutions.
84Mouth protectors are typically fabricated from what material?
- AThermoplastic polymer
- BImpression material
- CComposite
- DDenture base resin
- EGuttapercha
85Which of the following materials practically cannot be fabricated using CAD/CAM procedures?
- ADental porcelain
- BGold alloys
- CZirconia
- DAlumina
- EDental composite
86What process does not harm the protective titanium dioxide surface of dental implants?
- AScaling with metal instruments
- Buse of polishing agents
- Cabrasive dentifrices
- Ddental floss
- EAPF application
87Which one of the following dental materials fabrication processes would be classified as "additive"?
- ACAD/CAM machining of zirconia
- BAD/CAM machining of composite
- CInkjet printing
- DCasting
- EAll of the above
88What are the major requirements for tissue engineering?
- Acells and bone
- Bcells and collagen
- CCollegen, hydroxyapatite and signals
- Dcells and scaffolds
- Ecells, signals and scaffolds
89Which of the following biomaterials utilizes tissue from a cadaver?
- AAllograft
- BXenograft
- CSynthetic tissue
- DEngineered tissue
- EAutograft
90Which of the following is not a scaffold material for tissue engineering?
- AGold Mesh
- Bpolylactic acid (PLA)
- CBioglass
- DCollagen
- EBone chips
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- Public Health Quiz on Biomaterials, created by Dee-Anna L'Heureux on 02/04/2018.
- Author
- Dee-Anna L'Heureux
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- English
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