Dental Materials MCQs

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Multiple Choice Questions on Dental Material 

Dental Material MCQs are given for the preparation of Short Service Regular Commission fr those candidates who want to become Captain or Major in Pakistan Army. Joining Pakistan Army as a Commissioned Officers in Medical category is the best option for those who have their MBBS degree with specialization of Dental Field.

Dental Material is very important for those who are going to appear in the medcal examination of CSS, PSC, or FPSC or other competitive examinations for becoming a doctor. These question of dental material is the past experience of students who appeared in the medical tests and cleared the exam.

Dental Material MCQs are very useful for those who have applied for AFNS, SSC, or SSRC in Pak Army, Pak Navy or PAF and they want to study the material related to the initial tests of dental material. Questions are given below which can be converted into PDF or in some other suitable format like MS Word etc.

In admission entrance tests, dental material is very useful and help in passing the initial examination with full marks. Candidates who have degree of NDS and recognized by PN&DC then they must read these Dental MCQs thoroughly. This help in online examination also about medical field.

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Dental Materials MCQs for Preparation of SSRC

Important Dental Material MCQs are given below for the preparation of Short Service Regular Commission. 

A material behaves in certain ways above and below the proportional limit on a stress strin curve, which of the following is correct_______?

A. Above the proportional limit a material function in a plastic manner, while below the proportional limit it behaves as an elastic
B. Above the proportional limit a material functions in an elastic manner, while below the proportional limit it behaves as an plastic
C. Either A or B
D. Neither A or B

Which of the following is correct______?

A. Type I and Type II gold can be heat treated and annealed
B. Type III and Type IV gold can be heat treated and annealed
C. Type I and IV gold can be heat treated and annealed
D. All the type of gold can be heat treated and annealed

Which of the following is present in the powder of the acrylic resin______?

A. Methyl methacrylate
B. Benzoyl peroxide
C. Hydroquinone
D. D-methyl paratolouidine

Boiling point of methyl methacrylate________?

A. B.P of water
B. < B.P of water
C. Equal of BP of water
D. Is at normal room temperature

The main advantage of composites over unfilled direct filling resin is their______?

A. Higher solubility in saliva
B. Lower modulus of elasticity
C. Esthetic excellence
D. Lower thermal co-efficient of expansion

Composite has_______?

A. Resin
B. Filler
C. Resin & Filler
D. None

Acrylic resins are used for____?

A. Anterior restorations
B. Temporary bridges
C. Denture base
D. All of the above

To prevent porosity in self-cure acrylic resin, curing should be carried in_______?

A. Cold water
B. Hot water
C. Under tap water
D. Under vacuum pressure

Porosity present in a acrylic denture is usually the result of______?

A. A prolonged curing cycle
B. Lack of sufficient pressure applied to flask
C. Insufficient acrylic resin monomer
D. Prolonged bench cooling after curing

Cross linking in denture base resin is contributed by______?

A. Glycol dimetharylate
B. Benzoyl peroxide
C. N-para toluidine
D. Methyl methacrylate

Hydroquinone is added to methyl methacrylate monomer______?

A. To prevent polymerization during storage
B. To initiate release of free radicalls
C. To enable polymerization reaction at room temperature
D. All of the above

Which of the following inhibitor accelerator system uses light activation composite ?

A. Diketone-amine
B. Organic acid-metal oxide
C. Organic acid-peroxide
D. Peroxide-amine

Which of the following is an example of a composite material ?

A. A filled resin
B. Colloidal silica
C. Gold alloy
D. Wax

In heat cure denture base acrylic resins the monomer is______?

A. Methacrylate
2. Ethylmethacrylate
3. Methyl ethyl methacrylate
4. Polymethylmethacrylate

Light cure system, side effect is______?

A. Iritis
B. Cataract
C. Conjunctivitis
D. Retinal damage

Bonding of composite resins to tooth structure is by_______?

A. Covalent bond
B. Ionic bond
C. Mechanical
D. Vanderval forces

The type of spatula used to mix composite is_______?

A. Plastic
B. Stainless steel
C. Iron
D. None of the above

Which of the following may result if an excessive amount of monomer is incorporated into an acrylic resin mixture ?

A. Excessive expansion
B. Low impact strength
C. Excessive shrinkage
D. Excessive brittleness

Benzoin methyl ether in a polymer indicates that they may be cured in the presence of______?

A. UV light
B. Visible light
C. Infrared light
D. Diketone

Porosity of denture base is due to____?

A. Packing at dough stage
B. Curing at 160°F for 9 hrs
C. Inadequate pressure
D. All of the above

The imperfection seen on the lingual flange of a lower denture caused by rapid heating during a curing cycle is called_____?

A. Localized Shrinkage porosity
B. Gas inclusion porosity
C. Micro porosity
D. Surface porosity

The particle size in micro filled composites is______?

A. 0.05 to 0.04mm
B. 0.5 to 1.0 microns
C. 0.01 to 0.1 microns
D. 0.3 to 0.4mm

A material which is a mixture of two different materials and its properties are_____?

A. Composite
B. Complex material
C. Combined
D. Compound

Co-efficient of thermal expansion is highest for_____?

A. Amalgam
B. Silicate cement
C. Gold alloy
D. Acrylic resin

The latest method of curing denture base resins_____?

A. Heat
B. Visible light
C. Chemicals
D. Lasers

One of the claims for the superiority composite resin restoration over silicate cement restorations is that the resin restorations_____?

A. Prevent galvanic action
B. Are practically insoluble in oral fluids
C. Adapt to the walls of the cavity better
D. Have a higher coefficient of thermal expansion

To cure a heat cure resin, a proper heating cycle is necessary______?

A. To prevent the porosity
B. To prevent warpage
C. To prevent volume expansion
D. All of the above

When restoring a tooth with resin material, acid etching can do all of the following except_____?

A. Increase the surface area
B. Permit chemical bonding between resin and enamel
C. Create surface irregularities in enamel for better mechanical retention of resin
D. Condition the tooth surface for better wetting

For esthetic areas where high luster is required the restoration used usually_____?

A. Glass ionomer restoratives
B. Hybrid resin composites
C. Microfilled resin composites
D. Macrofilled resin composites

Which of the following absorbs maximum amount of water ?

A. Microfilled resin
B. Macrofilled resin
C. Hybrid
D. Light cure activated

The restoration which shows percolation and shrinkage along the margins is______?

A. Composites
B. Unfilled resins
C. Amalgam
D. Polycarboxylate

The commonly used laser for curing composite resin is______?

A. Nd:YAG
B. CO2
C. ER:YAG
D. Argon

What is the polymerization shrinkage if 3:1 powder: liquid ratio is used_____?

A. 6%
B. 8%
C. 10%
D. 21%

Macromolecules in Dental Resin is attached by_____?

A. Covalent bonds
B. sonic bonds
C. Vander Wall’s Forces
D. Hydrogen Bonds

Along with polymerisation shrinkage, one of the major disadvantages of polymethyl methacrylate as denture base resin are its poor______?

A. Biological properties
B. Thermal properties
C. Mechanical properties
D. Esthetic properties

The most common coupling agents are organic silicon compound called______?

A. Parabane
B. Ligane
C. Silane
D. Chelane

One bottle system of adhesive resins_____?

A. 4th generation bonding agents
B. Separate etching step not required
C. Separate etching step is still required
D. Contains only primer

Most advantageous indication of acid etching is_____?

A. Decrease micro leakage
B. Decrease polymerization shrinkage
C. Decrease coefficient of thermal expansion
D. Decrease porosity in restorative material

VLC resins are also called as_____?

A. Microwave-activated resins
B. Tertiary amine-activated resins
C. Light activated resins
D. Heat activated resins

Cold cure acrylic expand in water by______?

A. 1% by volume 0.23% by weight
B. 10% by volume 0.23% by weight
C. 0.1% by volume 0.23% by weight
D. None of the above

Which of the following is NOT true of polymethyl methacrylate ?

A. Knoop hardness number 18 to 20
B. Tensile strength of 60 MPa
C. Density of 1.13 g/cm3
D. Modulus of elasticity of 3.4 GPa

Etchant preferred in gel from than in liquid form_____?

A. Better control over placement
B. Enhance and concentrate the action of acid
C. Helps in visualization while placement
D. None of the above

During polymerisation of acrylic resin, above what temperature benzoyl peroxide form freeradicals_______?

A. 25°C
B. 37°C
C. 50°C
D. 60°C

Etching depth after 30 sec for orthodontic bracket with orthophosphoric acid is______?

A. 10 um – 20 um
B. 3 um – 9 um
C. 50 um – 110 um
D. 200 um – 250 um

The accepted polymer to monomer ratio for packing of polymethyl methacrylate resin is_______?

A. 3:1
B. 4:1
C. 10:1
D. 5:1

Residual monomer content of chemically activated resins is______?

A. 0.2% to 0.5%
B. 2% to 5%
C. 0.3% to 0.5%
D. 2% to 5%

Dentin conditioner has the following function_____?

A. Removes smear layer
B. Increases surface energy of dentin
C. Forms a thin resin layer over exposed collagen fibrils
D. Helps in bonding with composite

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_____?

A. Step-growth polymerization
B. Addition polymerization
C. Condensation polymerization
D. Copolymerization

Denture acrylics contain cross-linking agents mainly to improve their_____?

A. Internal color
B. Tissue compability
C. Surface hardness
D. Craze resistance

Subsurface porosity is due to______?

A. Thermal changes
B. Thickness of the resin
C. Lack of temperature
D. Packing past the dough stage

If resin is packed in sandy stage what will be seen in the processed denture ?

A. Distortion
B. Porosity
C. Inhomogeneous colour
D. Increased strength

Which one of the following is used as filler in composite resins ?

A. Quartz
B. Silicates
C. Zinc particles
D. Aluminium

Insufficient closure of the flasks during packing of denture base resin can result in______?

A. Poor colour stability
B. Less polymerization shrinkage
C. Increase in vertical dimension
D. Decrease in vertical dimension

Quartz tungsten light cure device minimum output of energy should not be less than_____?

A. 300 mw/sm2
B. 350 mw/cm2
C. 400 mw/cm2
D. 450 mw/cm2

Polymerisation of heat-cured methyl methacrylate is initiated by____?

A. Tertiary amine
B. Benzoyl peroxide free radical
C. Hydroquinone
D. Methyl ether

In processing methyl methacrylate, the resin may show porosity if the flask is placed too soon porosity most likely occur_____?

A. Throughout the denture
B. Near the borders
C. In the thickest part
D. On the denture surface

Composite resins in comparison to acrylic have______?

A. Low compressive strength
B. High abrasive resistance
C. High water absorption
D. High polymerization shrinkage

Insufficient closure of the flasks during packing of denture base resin can result in_____?

A. Poor colour stability
B. Less polymerization shrinkage
C. Increase in vertical dimension
D. Decrease in vertical dimension

Subsurface porosity is due to___?

A. Thermal changes
B. Thickness of the resin
C. Lack of temperature
D. Packing past the dough stage

If resin is packed in sandy stage what will be seen in the processed denture ?

A. Distortion
B. Porosity
C. Inhomogeneous colour
D. Increased strength

Which one of the following is used as filler in composite resins ?

A. Quartz
B. Silicates
C. Zinc particles
D. Aluminum

The chemical used to etch enamel is_______?

A. Zinc oxide
B. Methyl methacrylate
C. Phosphoric acid
D. Eugenol

Which of the following procedure is indicated to produce cross-linking in the polymerization of linear chains of acrylic______?

A. Addition of grain refining agents
B. Addition of difunctional monomers
C. Increasing the amount of heat required for linear polymerization
D. Incorporation of terminating agents

For photo-curing the composite resin the light source_____?

A. Should be held at a millimeter distance from the restoration
B. Need no protection while in us
C. Will cure composite upto a depth of 5 millimeter thickness
D. Is fiber optic

In self-cure acrylic resin, activator is____?

A. Toluidine
B. Quaternary ammonium compound
C. Benzoyl peroxide
D. Tertiary amine

Marginal leakage related to temperature change occurs to the greatest extent with_______?

A. Amalgam alloy
B. Unfilled resin
C. Composite resin
D. Direct filling gold

Acrylic resins were first introduced as a denture base material in_____?

A. 1925
B. 1937
C. 1951
D. 1956

What is the disadvantage of using composites as restorative material ?

A. Increased thermal conductivity
B. Decreased wear resistance
C. Decreased thermal conductivity
D. None of the above

The % of free monomer in a heat – cured acrylic resin is____?

A. 3% to 5%
B. 8% to 10%
C. 0.2% to 0.5%
D. 0.6% to 0.8%

Inadequate pressure application during flasking______?

A. Increases vertical dimension
B. Causes teeth to be shrunken in investment
C. Causes poor quality of colour
D. Causes fracture of denture

Inorganic phase of the composites aid in______?

A. Increasing the mechanical strength
B. Decreasing the coefficient of thermal expansion
C. Reducing the polymerization shrinkage
D. All of the above

About polymerization shrinkage of composite all are true, except_____?

A. Polymerization shrinkage is greater if bonded surface area is lesser than unbounded surface area
B. Polymerization shrinkage is high if within the enamel margins
C. Acid etching and priming will decrease polymerization shrinkage
D. Microleakage can occur because of polymerization shrinkage

The advantage of unfilled methyl methacrylate is that_______?

A. It can be finished smoothly
B. It has a low degree of flow
C. It’s non-irritation to pulp
D. It’s wear resistant is high

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Dental Materials MCQs for free download

Past papers of dental material mcqs are given for the preparation of medical tests examination in the NTS, AFNS, AMC and Short Service Regular Commission. 

Dentin bonding agents usually contain______?

A. Only Hydrophobic component
B. Only Hydrophilic component
C. Hydrophobic and hydrophilic component
D. Lyophillic and lyophobic component

Which of the following provide opacity to composite ?

A. TEGDMA
B. BIS-GMA
C. Ti02
D. None of the above

The polymerization of self-curing resin takes faster in______?

A. Cold water
B. Hot water
C. Under pressure
D. In vaccum

Acid-etching is done for_____?

A. 30 seconds
B. 60 seconds
C. 90 seconds
D. 120 seconds

No trail closure is necessary with which one of the technique during denture fabrication______?

A. Compression molding technique
B. Injection molding technique
C. Fluid resin technique
D. Light cured technique

The function of the coupling agent in a restorative resin is to allow______?

A. Adhesion of resin particles
B. Bonding between filler crystals
C. Bonding between filler and resin
D. Bonding between tooth and resin

Which of the following constituents is common in occlusal sealants, bonding agents, composite resins ?

A. BIS GMA
B. Polymethyl methacrylate
C. Benzoin methyl ether
D. Silica filter

The most important disadvantage of acrylic denture base is______?

A. porosity
B. Shrinkage
C. Tooth breakage
D. Water absorption

Radio opacity to composite resins is rendered by_____?

A. Silica glass
B. Organic matrix
C. Barium glass and strontium glasses
D. Fluoride particles

Acrylic (cold cure)___ ___?

A. Melts at 100°C
B. Softens at 100°C
C. Still requires heat for polymerization
D. Produces heat during polymerization

Use of dimethyl-P-toluidine is indicated for_______?

A. Thermal polymerization of acrylic
B. Chemical polymerization
C. Retarding the polymerization reaction
D. To inhibit the action of benzoyl peroxide

If curing occurs at temperature more than 100°C porosity results in which area of denture______?

A. Hard thick central area
2. Thin Palatal area
3. Thin area of flanges
4. Porosity is uniformly distributed

All of the following statements about the differences between self-polymerizing acrylic resins and heat-cured resins are true EXCEPT_____?

A. The former have a lower molecular weight
B. The former have higher residual monomer content
C. The former are more porous
D. The former have greater transverse strength

Deformation that is recovered upon removal of an externally applied force or pressure is known as_____?

A. Young’s modulus
B. Plastic strain
C. Elastic strain
D. Flexural strain

Co-efficienty of thermal expansion of tooth enamel is closest to______?

A. Silicate cement
B. Composite
C. GIC
D. Polycarboxylate

The forces that hold atoms together are called______?

A. Primary forces
B. Secondary forces
C. Cohesive forces
D. Ionic forces

A material which partially transmits light & partially scatters it______?

A. Reflector
B. Translucent
C. Transparent
D. Opaque

Angles between Adhesive and Adherent is Zero degree, it indicates_____?

A. Complete wetting of surfaces
B. Rough surfaces between Adhesive & Adherent
C. Adherent and Adhesive molecules are tangent to each other
D. Irregularities present between Adherent surfaces

Brazilian test is used to determine the ultimate tensile strength of_______?

A. Ductile materials
B. Flexible materials
C. Brittle materials
D. Malleable materials

For adhesion to be present between solid and liquid______?

A. Liquid should wet solid surface
B. Mechanical interlocking should be present
C. Should have high contact angle
D. None of the above

When two metals are completely miscible in liquid state and they remain completely mixed on solidification, the alloy formed is called_______?

A. Solid solution
B. Eutectic mixture
C. Peritectic mixture
D. Inter metallic compounds

A crystal in metal substructure is______?

A. Grain
B. Nucleus
C. Stroma
D. None of the above

Munsell system is used to_____?

A. Define and measure colour qualitatively
B. Define and measure physical properties of gold alloys
C. Evaluate brittleness of different alloys
D. Measures different colours quantitatively

Space lattice refers to______?

A. Inter atomic movement
B. Inter atomic imbalance
C. Arrangement of atoms
D. Arrangement of molecules

The strain that occurs when a material is stressed to its proportional limit is______?

A. Resilience
B. Maximum flexibility
C. Toughness
D. Elastic limit

Liquids which become more rigid as the rate of deformation increases is termed as_______?

A. Thixotropic
B. Pseudoplastic
C. Dilatant
D. Newton

A restorative material which has a high proportional limit, compared with one with a lower proportional limit would have_______?

A. Greater ductility
B. Greater toughness
C. A higher modulus of elasticity
D. A higher modulus of elasticity
E. More resistance to permanent deformation

Which of the following has the highest modulus of elasticity ?

A. Dentin
B. Enamel
C. Amalgam
D. Composite Resin

The wetting of an adherent surface by an adhesive is related to_______?

A. Surface energy of the adherent
B. Surface texture of the adherent
C. Surface tension of the adherent
D. Nature of the adherent that is crystalline or amorphous

Coefficient of thermal expansion of which of following is most similar to that of tooth ?

A. Gold inlay
B. Acrylic resin
C. Silicate cement
D. Gold foil

The stiffness of a dental gold alloy is determined by its______?

A. Proportional limit
B. Modulus of elasticity
C. Ultimate tensile strength
D. Flow

Ductility of a material is a measure of it’s______?

A. Grain elongation
B. Anealing
C. Cold working
D. Work hardening

Sublimation is the conversion of a______?

A. Solid directly to gas
B. Gas to liquid and then to solid
C. Gas directly to liquid
D. Solid to liquid and then to gas

Modulus of elasticity means______?

A. Rigidity or stiffness of the material
B. Ability to be stretched with permanent deformation
C. Ductility of a material
D. Malleability of the metal

When solid gets wet completely contact angle is______?

A. 90°
B. 0°
C. 0 – 90°
D. >90°

Brinnel hardness number of a dental gold alloy is directly proportional to its______?

A. Tensile strength
B. Elongation
C. Modulus of elasticity
D. Modulus of resilience

Hardness number which does not depend on the ductility of metal_____?

A. KNH
B. VHN
C. RHN
D. BHN

The greatest stress which may be produced in a material such that stress is directly proportional to the strain is know as______?

A. The elastic limit
B. The proportional limit
C. The yield strength
D. Modulus of elasticity

The modulus of elasticity is defined as_____?

A. The stress at the proportional limit
B. The strain at the proportional limit
C. The stress/strain ratio within the proportional limit
D. None of the above

Strain is defined as_____?

A. An applied load or force
B. A deformation resulting from an applied load
C. An external force opposing an applied load
D. An internal force opposing an applied load

A good adhesive should possess all of the following EXCEPT______?

A. High adherend wetting
B. High contact angle
C. Low contact angle
D. High flow

In measuring Vickers hardness no. Which of the following is used______?

A. Spherical indenter
B. Steel ball indentation
C. Rhomboid shaped indenter
D. 136-degree diamond pyramid

The simplest alloy is a______?

A. Solid solution
B. Eutectic alloy
C. Paratactic alloy
D. Ternary alloy

Materials which has high compressive strength and low tensile strength is classified with property of_____?

A. Ductility
B. Brittleness
C. Malleability
D. Resilient

Maxwell – Voigt Model is to determine_____?

A. Elastic Behaviour
B. Plastic Behaviour
C. Viscoelastic Behaviour
D. All of the above

KHN value of Amalgam is_______?

A. 90
B. 343
C. 67
D. 450

The melting point of silver is______?

A. 1063° centigrade
B. 960° Centigrade
C. 850° Centrigrade
D. 1123° Centigrade

Non metal which conducts electricity_____?

A. Graphite
B. Carbon
C. Acrylic
D. Porcelain

Etching of dentin does not include_______?

A. Removal of smear layer
B. Exposure of collagen fibers
C. Opening of dentinal tubules
D. Increases surface energy

The Knoop Hardness Number of Micro filled composite Restorative material ranges from______?

A. 50 – 60 KHN
B. 25 – 35 KHN
C. 15 – 20 KHN
D. 40 – 48 KHN

The elastic of plastic deformation to fracture a material is its_______?

A. Toughness
B. Brittleness
C. Young’s modulus
D. Proportional limit

KHN of enamel is close to_______?

A. Pure gold
B. Amalgam
C. Prcelain
D. Composite

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 ?

A. Fracture of the wire
B. permanent deformation
C. Spring back
D. Increase in stiffness

A fluid having constant viscosity that does not depend upon the strain rate is said to be_______?

A. Viscoelastic
B. Pseudoplastic
C. Plastic
D. Newtonian

Which of the following hardness test is a micro hardness test ?

A. Brinnel
B. Knoop
C. Shore-A
D. Rockwell

Which of the following properties of dental materials is time dependent______?

A. Creep
B. Resillience
C. Elastic limit
D. Ultimate strength

Flow of a material refers to______?

A. Continued change of the material under a given load
B. The consistency of material when mixing
C. The homogencity of gypsum products
D. Dimensional change of the material during settings

The ability of the base to resist occlusal forces and to support the restoration is affected by_____?

A. Compressive strength
B. Tensile strength
C. Young’s modulus
D. Modulus of elasticity

The ability of an alloy to withstand mechanical stresses without permanent deformation is reflected by its______?

A. Resilience
B. Elastic limit / Elastic strain
C. Hardness
D. Fatigue resistance

Which of the following physical property can be used to estimate indirectly the proportional limit of gold alloys ?

A. Vickers’s hardness number
B. Knoop hardness number
C. Brinell hardness number
D. Rockwell hardness number

Property of the material, which describes the resistance to abrasion, is_______?

A. Hardness
B. Yield strength
C. Modulus of elasticity
D. None of the above

Ultimate tensile strength refers to______?

A. Stress before rupture
B. Stress after rupture
C. Longitudinal compressive strength
D. Horizontal compressive strength

Ability of an orthodontic wire to spring back to its original shape is evaluated by_____?

A. Brittleness
B. Resilience
C. Tensile strength
D. Toughness

The point at which a stress of a material exhibits a specific limited deviation P is called_______?

A. Proportional limit
B. Tensile strength
C. Ultimate strength
D. Yield strength

Compressive stress is computed by dividing the external force by the______?

A. Area of the test specimen upon which the weight rests
B. Elasticity of the test specimen in strain
C. Length of the test specimen beneath the force
D. Strain of the test specimen per unit length

The proportional limit is defined as_____?

A. The maximum stress in a structure
B. The minimum force required to cause a structure to break
C. The maximum stress that can be induced without permanent deformation
D. The maximum elongation under tension that can be measured before failure

Stress in defined as______?

A. An applied load or force
B. A deformation resulting from an applied load
C. An external force opposing an applied load
D. An internal force opposing an applied load

Setting expansion is advantageous in______?

A. Casts
B. Models
C. Investment
D. Dies

Back pressure porosity can be avoided by_____?

A. Using asbestos linear
B. Placing the sprue at least one quarter inch away form the end of casting ring
C. Preventing rapid heating the investment in burnout oven
D. Using a short and wide sprue

Which of the following zones is used for melting alloy during casting______?

A. Reducing flame
B. Oxidizing flame
C. Green flame
D. All of the above

Cleaning of base metal alloy is done by______?

A. Warm HCI
B. Cold HF
C. Cold H2SO4
D. Sand blasting with aluminum oxide

Which one of the following is most elastic ?

A. a titanium
B. B titanium
C. Chrome-cobalt-nickel
D. Nickel-titanium

A thinner mix of a gypsum bonded investment will______?

A. Produce a smoother casting
B. Decrease setting expansion
C. Increase setting expansion
D. Increase thermal expansion

Stainless steel orthodontic wire can be hardened by_______?

A. Tempering
B. Work hardening
C. Age hardening
D. Precipitation hardening

Pickling____?

A. Is accomplished by soaking the casting in baking soda
B. Causes porosity in gold
C. Removes surface oxides from gold castings
D. Remove investment from gold casting

NiTi alloy have_______?

A. Shape memory
B. Hyper rigidity
C. Corrosion resistance
D. Weldable properties

The main form of iron carbide found in 18-8 steel______?

A. Martensite
B. Ferrite
C. Austenite
D. Pearlite

MCQs of Dental Materials for Medical Examination

If you want to give examination for the admission of medical tests in Army Medical College then learn all these question related to the Dental Material. 

The strength of a gypsum investment is dependent on______?

A. Carbon content
B. Silica content
C. Gypsum
D. Copper

Ideal requirement of metal ceramic casting______?

A. Low fusing ceramic and high fusing alloys
B. Matching of coefficients of thermal expansion of ceramics and alloy
C. Bonding between ceramic and alloy
D. All of the above

The pattern for the metallic framework of a removable partial denture is fabricated from_________?

A. Inlay wax type-II
B. Boxing wax
C. Modelling wax
D. Casting wax

The contraction of gold alloy on solidifying is approximately______?

A. 0.4%
B. 1.4%
C. 2.4%
D. 3.4%

Tempering of steel cause_______?

A. Increases its toughness
B. Increases hardness
C. Increase ductility
D. decreases its toughness

Which of the following will produce the most rigid restoration for framework of same dimension ?

A. Wrought alloy
B. Palladium alloys
C. Cobalt-chrome alloys
D. Partial denture casting gold in hardened condition

Apart from composites and ceramics, another material that could be copy milled easily and inexpensively is______?

A. Molybdenum
B. Germanium
C. Titanium
D. Chromium

Austenite is an alloy of iron of and carbon with the iron in_________?

A. Alpha form
B. Beta form
C. Gamma form
D. None of the above

Which zone is the hottest and efficient burning zone of the flame used for casting ?

A. Oxidizing zone
B. Reducing zone
C. Combustion zone
D. None of the above

Localized shrinkage porosity is seen when there______?

A. Thin sprue
B. No reservoir
C. Investment heated strongly
D. Inadequate air discharge

Sub surface porosity can be decreased by______?

A. Decreasing the sprue length
B. Decreasing the sprue thickness
C. Increasing the melting temperature
D. Increasing the mould temperature

The inlay wax most commonly used for direct technique_________?

A. Type 1
B. Type 2
C. Type 3
D. Type 4

The purity of gold is expressed in_______?

A. Carats
B. Percentage
C. Fineness
D. Gram

In a metal ceramic crown for a FPD the function of tin, indium which are readily oxidized minor constituents is to_____?

A. Improve bonding
B. Decrease porosity
C. They react with the porcelain opaque layer, which masks the metal
D. Improves the thermal expansion between the metal and porcelain

Investment material used for cobalt-chromium alloys is_____?

A. Gypsum bonded
B. Phosphate bonded
C. Silica bonded
D. None of the above

Silica sol______?

A. Is applied to the walls of the investment to produce hygroscopic expansion
B. Increase the strength and the setting expansion of the phosphate-bonded investment
C. Acts as a retarder in the silica bonded investments
D. Acts as a refractory in the Silica bonded investments

Boxing wax is also called as_______?

A. Carding wax
B. Inlay wax
C. Utility wax
D. Sticky wax

Shape memory in NiTi is because of stress induced form________?

A. Austenite to martensite
B. Martensite to austenite
C. Ferrite to austenite
D. Austenite to ferrite

Casting shrinkage is compensated by_______?

A. Thermal expansion
B. Hygroscopic expansion
C. Wax expansion
D. All of the above

The gold alloys used for casting contain at least…. percent of precious metal according to ADA specification number 5______?

A. 55
B. 65
C. 75
D. 85

Impurities in casting is removed by_____?

A. Annealing
B. Degassing
C. Pickling
D. Conditioning

Shape memory is seen in_______?

A. Stainless steel wire
B. NITTINOL wire
C. TMA wire
D. Aluminum

The best pickling solution for gypsum bonded investment is_______?

A. Hydrochloric acid
B. Nitric acid
C. Sulphuric acid
D. Phosphoric acid

Corrosion of stainless steel is due to formulation of_______?

A. Chromium carbide
B. Carbon carbide
C. Iron carbide
D. Nickel carbide

The rapid decrease in tensile strength and increase in ductility of a wrought metal is seen in which stage of annealing ?

A. Recovery stage
B. Recrystallisation stage
C. Grain growth stage
D. All of the above

Which one of the following categories of dental materials has the highest thermal conductivity_____?

A. Unfilled acrylic plastics
B. Gold alloys
C. Porcelains
D. Zinc phosphate cements

Most biocompatible material in oral cavity is______?

A. Platinum
B. Palladium
C. Titanium
D. Gold

Which of the waxes are derived from the lignite______?

A. Paraffin wax
B. Inlay wax
C. Microcrystalline wax
D. Montan wax

Silver plated dyes use an electrolytic bath of______?

A. Silver fluorides
B. Silver cyanide
C. Silver bromide
D. Silver iodide

Suck back porosity is due to______?

A. Attached impurities on undersurface of casting
B. Hot spot
C. No rapid cooling
D. Inadequate melting temperature

Air bubbles formed on the surface of casting is probably due to_______?

A. Improper casting pressure
B. Improper heating of the investment
C. Improper angulation of sprue
D. Improper wetting of the wax pattern by the investment

Asbestos liner is used in a casting ring to______?

A. Facilitate venting of the mold
B. Retard the heating of the investment
C. Permit expansion of the world
D. All of the above

Which of the following decrease with strain hardening_____?

A. Surface hardness
B. Strength
C. Proportion limit
D. Corrosion resistance

Suck back porosity in the casting can be eliminated by______?

A. Increasing the mould metal temperature difference
B. Increasing the flow of molten metal
C. Flaring the point of the sprue attachment
D. All of the above

The component in very minor quantity in stainless steel that changes the properties to a maximum level is______?

A. Carbon
B. Molybdenum
C. Chromium
D. Nickel

Binder used in Gypsum investment is______?

A. Silica
B. Quartz
C. Cristobolite
D. Calcium sulphate monohydrate

Nickel-Titanium alloy has______?

A. Unreliable spring back
B. low spring back
C. Minimal spring back
D. None of the above

Advantage of titanium over other base metal alloys______?

A. Low weight
B. Low cost
C. Low strength
D. Low melting point

Component of inlay wax which makes it flake resistant is____?

A. Paraffin
B. Carnauba
C. Gum dammar
D. Canadelila

Microstructure of cobalt chromium alloy in cast condition is______?

A. Fibrous
B. Homogeneous
C. Inhomogenous
D. amorphous

Dendrites in cst alloys form by mechanism of______?

A. Constitutional superconductivity
B. Constitutional supercooling
C. Constitutional supergriting
D. Constitutional supergraining

Compared with noble metals, base metals show_______?

A. Increased hardness
B. Increased ductility
C. Better biocompatibility
D. Increased density

Mechanical properties of Cp Titanium are similar to alloys_____?

A. Type III and Type IV gold
B. Type V and type VI gold
C. Type VII and type VIII gold
D. None of the above

The effects associated with cold working can be eliminated by a heat treatment called_____?

A. Age hardening heat treatment
B. Annealing heat treatment
C. Homogenization heat treatment
D. Solution heat treatment

With indirect sprucing. Which one of the following porosities can be minimized____?

A. Back pressure porosity
B. Localized shrinkage porosity
C. Pin hole porosity
D. Micro porosity

The linear solidification shrinkage of Type IV Ni-Cr based alloys is______?

A. 2.3%
B. 1.56%
C. 1.37%
D. 3%

Which of the following cast gold alloys is used for fabricating partial denture frameworks______?

A. Type I – Soft
B. Type II – Hard
C. Type III – Hard
D. Type IV – Extra Hard

Modern dental noble metal casting alloys generally have equiaxed fine grain structures because of the incorporation of small amounts of_______?

A. Chromium
B. Indium
C. Irridium
D. Palladium

Nickel is added to wrought gold alloys as_______?

A. Strengthener
B. Hardener
C. Whitens the alloy
D. Scavenger

Stages of annealing in order________?

A. Recovery recrystallization grain growth
B. Recrystallization recovery, grain growth
C. Grain Growth Recrystallization recovery
D. Melting point, grain growth, Recrystallization

The term ordered hardening heat treatment used in which of the following dental alloys ?

A. Gold-Copper
B. Nickel-Chromium
C. Nickel-Titanium
D. Silver-Palladium

Linear coefficient of thermal expansion of metal used for metal ceramic restoration range from____?

A. 11.5-12.5×10-6/°C
B. 10.5-11.5×10-6/°C
C. 13.5-14.5×10-6/°C
D. 16.5-17.5×10-6/°C

Quartz is added to gypsum bonded investment to___?

A. Increase the strength
B. Counter balance contraction of gypsum during heating
C. aid in hygroscopic expansion
D. Increase the shelf life of investment

Annealing is also known as______?

A. Soft hardening treatment
B. Hard hardening treatment
C. Precipitating heat treatment
D. Stress relieving heat treatment

The best fuel gas when used with oxygen is_______?

A. Hydrogen
B. Natural gas
C. Propane
D. Acetylene

Which of the following fuel gases is the best choice of heat source to carry out soldering process ?

A. Propane
B. Acetylene
C. Natural gas
D. Hydrogen

Solder and flux used for joining Elgiloy wires are_____?

A. Gold solder and borax flux
B. Gold solder and fluoride flux
C. Silver Solder and borax flux
D. Silver solder and fluoride flux

Fins and spines on the casting is seen due to_____?

A. Prolonged heating:
B. Rapid heating me
C. Water film contamination
D. Too high pressure during casting

The castability of chromium-cobait base metal alloys when compared to gold based noble metal alloys is_____?

A. More
B. Less
C. Equal
D. Depends on the alloy type

In Base metal alloys, Corrosion resistance occurs due to______?

A. Passivity
B. High Fusion Temperature
C. High Molecular Weight
D. Co-efficient of Thermal Expansion

The solvent flux used for base metal soldering is_______?

A. Boric acid
A. Borax
B. Fluoride
C. Rouge

During soldering, the solidus temperature of the filler material should be_______?

A. Greater than the substrate material
B. Lesser than the substrate material
C. Equal to the substrate material
D. Temperature not relevant

Which of the following increases CA stability of base metal alloys_______?

A. Tin
B. Beryllium
C. Molybdenum
D. Carbon

Which of the following fuel gases used for soldering, has the highest heat content_______?

A. Hydrogen
B. Natural gas
C. Acetylene
D. Propane

Binder in phosphate bonded investment is________?

A. Magnesium oxide & Phosphate
B. Magnesium oxide & Phosphoric acid
C. Magnesium oxide & Monoammonium phosphate
D. Magnesium oxide & Ortho Phosphoric acid

Which one of the following elements is NOT added is small amount to be used as grain refiners ?

A. Iridium
B. Ruthinium
C. Indium
D. Platinum

Within an hour after cementation of cast gold on lay patient complains of shooting pain every time the teeth comes together Most probable explanation is ________?

A. Supracocclusion of restoration
B. Retained cement in gingival sulcus
C. Excess acid in mix
D. Galvanic current caused by gold onlay occluding with a large restoration

The rate of tarnish and corrosion of class II cast material having VHN 200 is_______?

A. 0%
B. 2 to 3%
C. 5 to 10%
D. <1%

Function of wetting agents used in casting procedure is______?

A. To felicitate wetting of ring liner
B. To felicitate mixing investment
C. To reduce contact angle of liquid with max surface
D. For better wax elimination

The deoxidizing agent added to dental alloys is_____?

A. Palladium
B. Silver
C. Copper
D. Zinc

Which of the following is function of fluoride flux in soldering process ?

A. It prevents the formation of copper oxide
B. It prevents the formation of chromium oxide or dissolves chromic oxide layer
C. It prevents the flow of material in undesirable area
D. Increase the strength of solder

Percentage of gold in high noble alloy is______?

A. N 25%
B. 25%
C. >40%
D. 0%

Gases dissolved in molten metals are liberated when cooled giving rise to_____?

A. Suckback porosity
B. Gas inclusion porosity
C. Localized shrinkage porosity
D. Microporosity

Casting flux is used to_____?

A. Prevent the oxidation of the metal during melting
B. increase the melting point of the flux
C. Flaring the point of the sprue attachment
D. None of the above

The main ingredient of inlay wax is_______?

A. Candellila wax
B. Paraffin wax
C. Carnauba wax
D. Gum dammar

Who was the first person to introduce cast inlay restoration into dentistry ?

A. William H Taggart
B. Buonocore
C. G.V. Black
D. Bowen

Disadvantage of having a short sprue is______?

A. Rapid solidification of metal
B. No place for reservoirs
C. Incomplete evacuation of gases
D. Difficulty in removing casting from investment

18-B Stainless steel orthodontic wire has_____?

A. 18% Nickel 8% Chromium
B. 18% Chromium 8% Nickel
C. 18% Chromium 8% Cobalt
D. 18% Carbon 8% Iron

Inlay wax is used to_____?

A. Temporarily cement inlays:
B. Make inlay wax patterns
C. Invest inlay patterns
D. Box models

Quartz in investment material is added for_______?

A. Strength
B. Expansion components for casting shrinkage
C. Decrease strength
D. Contraction

The sprue in wax pattern should be placed_____?

A. At right angle
B. At 45°C angle
C. At obtuse angle
D. It depend upon type of wax pattern

Gold content of an 18 carat alloy is_____?

A. 25%
B. 50%
C. 75%
D. 100%

Titanium casting is done____?

A. Under vacuum in argon atmosphere
B. Under air pressure in nitrogen atmosphere
C. In specially fabricated aluminium vanadium
D. Using CAD-CAM technique

Heat hardening is the process done at_______?

A. Heating 750°C and slowly cooling to zero degree
B. Heating quickly upto 450°C followed by sudden quenching
C. Heating upto 250°C for 15 to 30 min
D. Heating at 750°C and then quenching to room temperature

Crucible indicated for casting base metal alloys is_____?

A. Carbon crucible
B. Clay crucible
C. Quartz crucible
D. High melting plastic crucible

Which of the following refractory is used to counteract most of the expansion______?

A. Quartz
B. Cristobalite
C. Tridymite
D. Corundum

Passivating alloys are_____?

A. Cr, Al, Ti
B. Cr, Mo, Ti
C. Cr, Gold, Ti
D. Cr, Fe, Ti

Waxes are used for_______?

A. Primary impression
B. Corrective impressions
C. Impression of single tooth
D. None of the above

A common electrolyte used for plating copper indirect dies is______?

A. Copper cynide
B. Ionic copper
C. Acidic copper sulfate
D. Silver cyanide

Stainless steel is used mostly in dentistry_______?

A. To strength amalgam
B. In orthodontic wires
C. To construct clasps for partial dentures
D. To replace internal gold restorations

The base constituents of dental waxes come from three main sources except_______?

A. Animal
B. Mineral
C. Insect
D. Vegetable

The standard perforated tray for us with alginate impression materials may be brought to more customized contour by_____?

A. Utility wax
B. Base plate wax
C. Beading wax
D. Boxing wax

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________?

A. Pinhole porosity
B. Gas inclusion porosity
C. Micro porosity
D. Subsurface porosity

Function of carnauba wax_____?

A. To provide a smooth and glossy surface
B. Increase toughness
C. Decrease toughness
D. Decrease flow at room temperature

Reduction in the fusion temperature of dental gold casting alloys is caused by presence of______?

A. Platinum
B. Copper
C. Silver
D. Gold

Softening heat treatment of alloy increases________?

A. Tensile strength
B. Proportional limit
C. Ductility
D. Hardness

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

Stabilization of stainless steel is achieved by adding______?

A. Carbon
B. Chromium
C. Nickel
D. Titanium

Dental Materials MCQs for NTS, PPSC, FPSC, AFNS, SSC Tests

Important Dental Material MCQs are given for those who want to give tests of NTS, FPSC, AFNS, SSC, and SSRC which are the past experience of the students who passed the examination. 

The yield strength of Austenite (NiTi alloy) is____?

A. 100 Mpa
B. 240 Mpa
C. 560 Mpa
D. 700 Mpa

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

Tublulence of molten gold is due to ______?

A. Impurities in gold
B. Improper venting
C. A and B
D. None of the above

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

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

Mouth temperature waxes are____?

A. Iowa wax
B. Modeling wax
C. Green stick wax
D. None of the above

Incomplete casting is the result of______?

A. More porous investment in the mould
B. Narrow sprue diameter
C. Hollow sprue pin
D. Large reservoir

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

Gypsum bonded investment should not be heated over______?

A. 700°C
B. 1,300°C
C. 1,063°C
D. 900°C

Cobalt-Chromium alloys contains______?

A. 30% cobalt and 60% chromium
B. 60% cobalt and 30% chromium
C. 1% palladium
D. 20% gold

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

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

The maximum carbon content of steel used in dentistry is_______?

A. 19%
B. 2%
C. 1.7%
D. 4%

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

Resistance to corrosion in a cobalt-chrome casting is due to presence of_______?

A. High quality iron
B. Chrome
C. Cobalt
D. Nickel

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

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

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

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

4th state of matter is______?

A. Solid
B. Liquid
C. Gas
D. Colloid

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

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

The term given to the phenomenon of moisture absorption by an alginate impression in_____?

A. Imbibition
B. Syneresis
C. Hysteresis
D. Gelation

The impression with the least dimensional change upon disinfection is________?

A. Addition poly silicone
B. Agar-agar
C. Polysulphide
D. Polyether

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

Immediate pouring of impressions is most critical in_____?

A. Condensation polysillicon
B. Addition Polysilicon
C. Polyether
D. A and B

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

Alginate impression material is______?

A. Non-elastic impression material
B. Thermoplastic impression material
C. More mucostatic than ZOE
D. Less mucostatic than ZOE

Syringe material is______?

A. High viscosity elastomer
B. Medium viscosity elastomer
C. Medium & low viscosity elastomer
D. Low viscosity elastomer

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

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

Which material undergoes hysteresis ?

A. Irreversible hydrocolloid
B. Reversible hydrocolloid
C. Impression plaster
D. Metallic oxide paste

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

Rubber base impressions are poured immediately as they______?

A. Continue to polymerize
B. Become elastic
C. Show imbibition and syneresis
D. Show gelation

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

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

Palatal secretions affect the setting of all the impression materials except______?

A. Silicone
B. Agar-agar
C. Impression paste
D. Impression plaster

Lenolin is added is ZOE paste to____?

A. Decrease flow
B. Increase flow
C. Accelerate reaction
D. Decrease irritation due to eugenol

Agar is prepared from______?

A. Bullock heart
B. Chemicals
C. Sea weed
D. Chick cells

Perforated impression tray are used for______?

A. Alginate
B. Zinc oxide-eugenol
C. Agar-agar
D. Impression compound

During setting of alginate impression materials_______?

A. Trisodium phosphate reacts with sodium alginate
B. Trisodium phosphate reacts with calcium sulphate
C. Colloidal changes to sol
D. Material in contact with soft tissues sets last

K2SO4 in agar-agar is for_______?

A. Accelerating the setting stage of gypsum
B. Increase strength
C. Give dimensional stability
D. None of the above

Wash or corrective impression is done by______?

A. Impression plaster
B. Impression paste
C. Alginate
D. Rubber base impression material

The plasticizers used in polyether impression material is_______?

A. polyether polymer
B. Colloidal silica
C. Glycol ether
D. Di-vinyl poly (dimethyl siloxane)

In reversible hydrocolloid the property by which the transformation from sol to gel and gel to sol is a function of the______?

A. Concentration of filler and plasticizer
B. Percentage composition by weight of water
C. Concentration of potassium sulphate
D. Temperature

Alginates are______?

A. Sol
B. Gel
C. Hydrocolloid
D. Colloid

Syneresis is associated with_____?

A. Hydrocolloids
B. Elastomers
C. Zinc oxide eugenol
D. Plaster of Paris

The advantage of ZOE impression paste_____?

A. Has dimensional stability
B. Does not adhere to tissues
C. Is easy manipulation
D. Does not require special trays

Rinsing of the impression is important to_____?

A. Remove excess impression material
B. Remove saliva
C. Hydrate the impression
D. Accelerate the setting

Which is best material for RPD impression_______?

A. Impression plaster
B. Irreversible hydrocolloid
C. Reversible hydroollioid
D. None of the above

Which of the following is not affected by saliva ?

A. Impression plaster
B. Impression paste
C. Silicon impression material
D. None of the above

Retarder in Zinc oxide eugenol is_____?

A. CaCl2
B. Zinc acetate
C. Alcohol
D. Glycerine

The cross linking agent of polysulphide rubber base impression material is_______?

A. Aromatic sulfonate esters
B. Stannous octate
C. Platinum salt catalyst
D. Lead dioxide

When making a polysulphide impression for a caste crown, custom trays are usually preferred over stock trays for all of the following reasons except_______?

A. Custom trays facilitate uniform contraction of impression material
B. Custom trays require less impression material
C. Stock trays may be short in the flange area
D. Impressions made n the custom trays are easier to remove from the mouth

Name the accelerator used in Zinc oxide eugenol paste_____?

A. Olive oil
B. Linseed oil
C. Zinc acetate
D. All of these

Linear contraction of elostomeric impression with passage of time is highest in________?

A. Addition silicone
B. Polysulphide
C. Polyetner
D. Condensation silicone

Which of the following is true about Agar hydrocolloid impression material ?

A. Liquefies between 71 – 100°C
B. Solidfies between 50 – 70°C
C. Facilitates fabrication of metal dyes
D. Cannot register fine surface details

Which one of the following increase the strength and reduce viscosity of agar hydrocolloid impression material_____?

A. Borax
B. Water
C. Sulfates
D. Carbonates

The water powder ratio of alginate is_____?

A. 100 ml of water to 60 gms of powder
B. 40 ml of water to 40 gms of powder
C. 40 ml of water to 15 gms of powder
D. 15 ml of water to 40 gms of powder

Best impression material to be used for securing impression after crown preparation____?

A. Alginate
B. Agar
C. Elastome
D. Zno paste

Which of the following is correct glass transition temperature of Impression compound ?

A. 43.5°C
B. 39°C
C. 65°C
D. 100°C

Rough and irregular surface produced on the impression is because of______?

A. Air incorporated during mixing
B. Improper application of pressure during impression making
C. Presence of excessive saliva in impression area
D. Due to improper ratio of polymer and monomer

Minimum flow of Type-I impression compound at mouth temperature is______?

A. 4%
B. 6%
C. 8%
D. 10%

Polysulfide material is routinely not recommended because of_____?

A. Unpleasant odor and taste
B. Low accuracy
C. Least permanent deformation
D. Highest curing shrinkage

Hydrocolloid material, show all except_______?

A. Hysterisis
B. Imbibition
C. Recrytallisation
D. Syneresis

Impression material that Do NOT harden by chemical reaction_______?

A. Zinc oxide eugenol
B. Impression compound
C. Alginate
D. Plaster of Paris

Putty wash technique_______?

A. Light body and putty used at the same time
B. Putty used first and light body used second
C. Light body first and putty later
D. None of the above

What is the minimum thickness of the elastomeric impression material for an accurate impression______?

A. 2 mm
B. 2-4 mm
C. Greater than 3 mm
D. Maximum in the area of operation

The relative hardness of elastomere is determined using_______?

A. Rockwell tester
B. Barcol indenter
C. Knoop pyramid
D. Shore durometer

Rough surface of elastomeric impression results from____?

A. Inadequate mixing
B. Air bubbles
C. Too rapid polymerization
D. Incomplete polymerization caused by premature removal from mouth

Most rigid elastomer is_______?

A. Polyether
B. Polysulphide
C. Addition silicone
D. Condensation silicone

Most ideally elastic among the following_______?

A. Polyether
B. Addition silicone
C. Polysulphide
D. Condensation silicone

Which one of the following impression materials is elastic, sets by a chemical reaction and is catalyzed by chloroplatinic acid______?

A. Condensation silicone
B. Polyether
C. Polysulfide
D. Poly vinyl siloxane

Which of the following best describes the working time of elastomeric impression material ?

A. After the start of appearing elastic properties of impression material
B. Just after the start of appearing elastic properties of impression material
C. Just before the start of appearing elastic properties of impression material
D. Loss of luster of impression material

Final product in alginate is_______?

A. Sodium alginate
B. Potassium alginate
C. Trisodium phosphate
D. Calcium alginate

Dustless alginate is produced by____?

A. Reducing the diatomaceous earth
B. Adding heavy metal salts
C. Coating with dihydric alcohol
D. Altering the matrix

Two in one stage impression materials include________?

A. Zinc Oxide eugenol impression paste
B. Hydrocolloid impression material
C. Elastomeric impression material
D. All of the above

A technique of combining reversible and irreversible hydrocolloid that could bond to irreversible hydrocolloid is known as________?

A. Injecting technique
B. Laminate technique
C. Immersion technique
D. Tempering technique

Which of the following impression materials is easy to pour and difficult to remove the stone cast from the impression ?

A. Addition polysilicone
B. Condensation polysilicone
C. Polyether
D. Polysulfide

Rough and irregular surface produced on the impression is because of ?

A. Improper application of pressure during impression making
B. Air incorporated during mixing
C. Too rapid polymerization
D. Presence of moisture in impression area

The impression materials with lowest viscosity is______?

A. Plaster of Paris
B. Agar – agar
C. Zinc oxide eugenol
D. Elastomers

The ranking of tear strength from the lowest to highest of all impression materials generally is as follows_______?

A. Hydrocolloids, silicones, polyether, polysulfide
B. Silicones, hydrocolloids, polyether, polysulfide
C. Polysulfide, hydrocolloids, silicones, polyether
D. Hydrocolloids, polyether, silicones, polysulfide

Most mucostatic among the following_______?

A. Impression compound
B. Alginate
C. ZOE paste
D. Elastomer

Which of the following impression material requires a hardener ?

A. Agar
B. Alginate
C. Elastomers
D. Impression compound

Dental Materials MCQs for Competitive Exam Preparation

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By product of condensation reaction between silicone base and alkyl silicate in presence of tin octoate________?

A. Ethyl alcohol
B. Glycol
C. Acetate
D. Propanolol

Which of the following component acts as an accelerator in ZOE impression paste ?

A. Zinc Sulphate & Zinc chloride
B. Zinc chloride & Eugenol
C. Zinc Sulphate & Eugenol
D. Glycerin

Dimensional stability of elastomeric impression material can be given in descending order as________?

A. Polysulphide > polyether > Condensation silicone > Addition silicone
B. polyether > Condensation silicone > Polysulphide > Addition silicone
C. Addition silicone > polyether > Polysulphide > Condensation silicone
D. Addition silicone> Condensation silicone > Polysulphide > polyether

A laminate impression technique utilizes______?

A. Syringe agar and chilled tray alginate
B. Syringe agar and tray agar
C. Syringe agar and impression compound
D. Chilled alginate and impression compound

Most flexible impression material_______?

A. Impression compound
B. Impression paste
C. Addition silicone
D. Alginate

Which of the following is correct arrangement of impression material regarding linear contraction in ascending order ?

A. Addition silicone < polyether < polysulfide < condensation silicone
B. Addition silicone < polysulfide < Polyether < condensation silicone
C. condensation silicone < polyether < polysulfide < Addition silicone
D. condensation silicone < polysulfide < polyether < Addition silicone

Which of the following best describes the working time of impression material ?

A. After the start of appearing elastic properties of impression material
B. Just after the start of appearing elastic properties of impression material
C. The time for start of mixing till just before the start of appearing elastic properties of impression material
D. Loss of lusture of impression material

Which of the following is used as surface hardener in Impression material ?

A. 2% Potassium sulfate
B. 0.2% Potassium sulfate
C. 2% sodium sulfate
D. 4% Potassium sulfate

Which of the following is correct regarding chemical setting of condensation silicone_____?

A. Polymerization occurs with repeated elimination of small molecules
B. Polymerization occurs with elimination of single byproduct
C. By condensation of repeated molecules of monomers
D. Condensation does not occur at all

Dimensional stability of hydrocolloid impressions may be achieved by______?

A. Using less water powder ratio
B. Storing the impression under water
C. Prolonged manipulation
D. Using humidor

To make the vinyl Polysiloxane hydrophilic the following is added______?

A. Mineral oil
B. Surfactant
C. Water
D. Plasticizer

The role of magnesium chloride in zinc oxide eugenol impression paste_______?

A. Retarder
B. Modifier
C. Plasticier
D. Accelerator

Alginates are made dust free by adding______?

A. Glycol
B. Glyecrol
C. Glutamic acid
D. alcohol

The process of changing the rubber base product or liquid polymer, to a rubber like material is generally known as______?

A. Boiling
B. Condensation
C. Vulconization
D. Chain lengthening

Which of the following is not true about elastomeric impression ?

A. Single mix material have higher viscosity
B. Shear thinning is related to viscosity of non phase impression material
C. Improper mixing of material can cause permanent deformation of impression
D. Putty – wash technique of impression reduces dimensional change of setting

Impression compound is characterized by all of the following except________?

A. Warps at room temperature
B. Is a thermoset material
C. Shows increased flow when kneaded with water
D. Low coefficient of thermal conductivity

Rapid removal of rubber impression with a single firm motion results in________?

A. Reduced dimensional instability
B. Improved adhesion of the impression to the tray
C. Minimal permanent deformation
D. Reduced contamination by saliva

Which of the following impression material is rigid ?

A. Zinc oxide-eugenol
B. Reversible hydrocolloid
C. Alginate
D. Polysulphide rubber

Elastomers except: Polyether are_______?

A. Hydrophilic
B. Hydrophobic
C. Water loving impression materials
D. Potassium alginates

Hardening solutions are used with impression made of______?

A. Hydrocolloid
B. Impression compound
C. Elastomer
D. Zinc oxide eugenol

Alginate impression material is similar to Agar-agar impression material in the following respect______?

A. Gelation increase in both on increase in temperature
B. Mixing time is increased to reduce the setting time
C. Deformation during removal of impression occurs due to distortion of gel fibers
D. Both can be re-used for fresh impressions

Gelation temperature of agar is between_______?

A. 20°C to 25°C
B. 27°C to 33°C
C. 37°C to 50°C
D. 55°C to 60°C

Brush heap structure is found in______?

A. Zinc oxide impression material
B. Agar
C. Condensation silicone
D. Polyether

Masterial causing minimum tissue distortion is_____?

A. Polysulphide
B. Silicone
C. Impression plaster
D. Zinc oxide eugenol paster

Inelastic impression material is____?

A. Impression compound
B. Alginate
C. Agar-agar
D. Polyether

One of the most important advantages of truly elastic impression material would be its capacity for_____?

A. Close adaptation to soft tissues
B. With drawl without permanent distortion
C. Reproduction of surface details
D. Compatibility with gypsum products

Impression compound base_______?

A. Low thermal conductivity
B. Crystalline structure
C. Formation of cross linkage with heating
D. High fusion temperature

Hypersensitivity reactions like contact dermatitis can be caused by______?

A. polysulfides
B. Condensation silicone
C. addition silicones
D. Polyether

Trisodium phosphate in alginate acts are_____?

A. Retarder
B. Reactor
C. Accelerator
D. Plasticizer

Which of the following impression material is elastic_______?

A. Impression compound
B. Zinc Oxide eugenol (ZOE) paste
C. Wax
D. Polyvinyl siloxane

The American dental association (ADA) specification number for non-aqueous elastomeric dental impression material is_______?

A. 19
B. 20
C. 21
D. 26

Elastomers are_______?

A. Alginate
B. Agar
C. Polyethers
D. Imp. Compound

Tear strength for impression material is highest for______?

A. Condensation silicone
B. Alginate
C. Polysulfide
D. Addition silicone

Trisodium phosphate added to alginate contributes towards_______?

A. increasing the working time of alginate impression material
B. Acts as an accelerator
C. Initiating the setting reaction
D. Provides gel strength

Agar syringe material can be used with/as_______?

A. Agar
B. Alginate impression material
C. Both of the above
D. Primary impression

Impression compound has which of the following characteristic property ?

A. Low thermal conductivity
B. High flow property
C. Degradation is presence of moisture
D. Remain distortion free up to 72 hrs. pouring can be safely delayed

Heavy and light body impression materials are use with________?

A. Mercaptan
B. Silicone
C. Reversible hydrocolloid
D. A and B

Which material is the most difficult to remove from the patients mouth ?

A. Metallic oxide paste
A. Silicone impression material
B. Reversible hydrocolloid
C. Impression plaster

Before pouring an elastic impression it is washed with slurry of water and stone to_______?

A. Increase gel strength
B. Prevent syneresis
C. Prevent distortion
D. Wash off saliva on impression

The basic constituent of reversible hydrocolloid impression material is______?

A. Agar
B. Alginic acid
C. Gelatin
D. alginate

Sol – gel transformation is seen in________?

A. Impression plaster
B. Hydrocolloids
C. Elastomer
D. Impression compound

Setting time of ZOE is best controlled by________?

A. Adding a drop of eugenol
B. Adding a drop of water
C. Cooling the glass slab
D. Altering ratio of two pastes

Impression plaster is______?

A. Less compressive than alginate
B. More compressive than alginate
C. As compressive as alginate
D. More compressive than hydrocolloids

Vulcanization refers to the setting of________?

A. Reversible hydrocolloid
B. Mercaptan impression material
C. Zinc Phosphate cement
D. Zinc oxide-eugenol

Impression techniques are used for recording_____?

A. Oral mucosal tissues
B. Dental hard tissues
C. Oral mucosal tissues and dental hard tissues
D. None of the above

Syneresis seen in hydrocolloid gel is______?

A. Seen as water loss
B. Water absorption
C. Shrinkage
D. Gelation

Best material for duplicating cast is______?

A. Agar-agar
B. Alginate
C. Zinc oxide eugenol
D. Plaster of paris

The base paste of the condensation poly sillicone has a low molecular weight dimethyl siloxane with a terminal-group______?

A. Marcaptan group
B. Hydroxyl group
C. Silane group
D. Virryl group

Hysteresis in a hydrocolloid gel is_______?

A. Moisture absorption
B. Temperature lag between gelation and liquefaction temperature
C. Phenomenon of conversion of gel into sol
D. All of the above

All of the following can be used to slow down the setting of Zinc oxide eugenol impression paste EXCEPT_______?

A. Adding a small amount of glycerin
B. Adding a small amount of water
C. Altering the amounts of the two pastes used
D. Cooling mixing slab

All of the following statements about Type II silicon impression material are true EXCEPT______?

A. They evolve hydrogen when cast if they are not fully cured
B. They exhibit a very low setting shrinkage
C. They have a lower tear resistance than polysulphide rubbers
D. They set by condensation polymerisation

The Zinc oxide-eugenol impression pastes harden by_______?

A. Chemical reaction
B. Cold
C. Heat
D. Pressure

Plaster mix_____?

A. Rapid spatulation results in decreased setting time
B. 2% potassium sulphate is accelerator
C. Citrates are retarders
D. All of the above

A rough / Chalky surface of the cast is due to________?

A. Not waiting for 20 min before pouring
B. High speed accelerator
C. Air incorporation in the mix
D. All of the above

The setting expansion of gypsum products can be reduced by______?

A. Increased spatulation
B. Adding potassium sulfate
C. Less water powder ratio
D. Allowing setting under water

Most commonly used retarder in gypsum_______?

A. Na2 So4
B. Nacl
C. Citrales
D. K2So4

Gypsum product having least expansion_______?

A. Impression plaster
B. Model plaster
C. Stone plaster
D. Die stone

Gillmore needle is used for______?

A. Testing the strength of plaster of Paris
B. Evaluating the setting time of plaster of pris
C. Testing the metal hardness
D. Testing the purity of noble metals

Setting of POP is result of_____?

A. Difference in solubility of CaSO4 ½ H₂O + CaSO4+ 2H₂O
B. Reaction between CaSO4+ 2H2O and water
C. Nucleation and growth of CaSO4 ½ H₂O crystals
D. Reaction between hemihydrate and hihydrate

Type I gypsum product is also called_______?

A. Impression plaster
B. Class I stone / Hydrocal
C. Class II stone/Densite
D. Model plaster

Plaster of Paris ______?

A. Is wet calcined hemihydrate
B. Has porous and irregular crystals
C. Is a – hamihydrate
D. Has a W / P of 0.2

As per DNA No. 25, minimum amount of setting expansion required for type V gypsum products____?

A. 0.05
B. 0.10
C. 0.15
D. 0.20

The main difference between dental stone and dental plaster is_______?

A. Chemical composition
B. Self life
C. Sharpe and size of particles
D. Solubility in water

Gypsum is used for______?

A. Impressions
B. Casts
C. Die
D. Casts and Dies

The strength of the gypsum specimen when the water in excess of that required for the hydrate of the hemihydrate is left in the specimen is called______?

A. Dry strength
B. Green strength
C. Water strength
D. Compressive strength

Balanced stone is dental stone______?

A. Which undergoes rapid expansion
B. In which accelerators or retarders have been added according to need
C. In which amount of water of hydration is controlled
D. In which the crystals are all of uniform size

Impression plaster containing potato starch is called______?

A. Plaster of Paris
B. Soluble plaster
C. Anti – expansion solution
D. Die stones

Powders of dental plaster and dental stone differ mainly in_____?

A. Solubility
B. Shelf life
C. Chemical formula
D. Particle porosity

Beta hemihydrate particles absorb_______?

A. More water
B. Less water
C. no water
D. None of the above

Type III Dental gypsum is______?

A. Class II stone
B. Densite
C. Class I stone or hydrocal
D. Model or lab plaster

The product, which is obtained by calcining gypsum under steam pressure at 120-130°C or by dehydrating gypsum in the presence of sodium succinate is_______?

A. Alpha – hemihydrates
B. Beta – hemihydrates
C. Calcium sulphate dihydrate
D. Orthorhombic anhydrate

The strength of gypsum prouducts is generally expressed in terms of______?

A. Tensile strength
B. Wet strength
C. Green strength
D. compressive strength

The function of 2% potassium sulphate in a gypsum product is______?

A. To regulate the setting expansion
B. Regulate setting time
C. Acts as retarder
D. None

Finer particle size of silica______?

A. Slower the hygroscopic expansion
B. Greater the hygroscopic expansion
C. Normal setting expansion
D. No setting expansion

ADA specification number of gypsum products are described under______?

A. 1
B. 4
C. 12
D. 25

Modiffiers are added to gypsum mainly to______?

A. Modify setting time
B. Modify setting expansion
C. Modify strength
D. Decrease the porosity

Placing cast under tap water is to be avoided as______?

A. H2O interferes with hygroscopic expansion
B. H2O inhibits polymerization of dental resin
C. H2O interferes with Crystallization of dihydrate
D. Gypsum is slightly soluble in water and the surface of the cast will be eroded

The β (Beta) hemihydrate of gypsum requires more water to float its powder particles because______?

A. They are more regular in shape and dense
B. They are more regular in shape and highly porous
C. They are more irregular in shape and porous
D. They are more dense and prismatic in shape

In plaster of paris the setting time is primarily altered by______?

A. Altering P / L Ratio
B. Altering temperature of mixing water
C. Speed and length of hand spatulation
D. Addition of accelerators and retarders

Which is gypsum product________?

A. Stone
B. Plaster
C. Investment
D. All of the above

The most commonly used accelerator in gypsum product is______?

A. Sodium fluoride
B. Potassium fluoride
C. Potassium sulfate
D. Aluminium sulfate

The hygroscopic technique is associated with_____?

A. Investment
B. Hydrocolloids
C. Amalgam
D. Silicate

Accelerators and retarders are used with gypsum products mainly to control______?

A. Setting time
B. Setting expansion
C. Hardness of the set product
D. None of the above

The main ingredient in dental plaster in_____?

A. Calcium sulphate hemihydrate
B. Calcium phosphate
C. Calcium anhydrate
D. Calcium sulphate dihydrate

Die is_______?

A. Impression of single tooth
B. Impression of whole teeth
C. Replica of single tooth
D. Replica of whole teeth

Plaster of Paris is mixed in________?

A. Plastic bowl
B. Rubber bowl
C. Glass bowl
D. Metal bowl

Water of reaction needed to react completely with 100 g of calcium sulphate hemihydrates to convert it to calcium sulphate dihydrate_____?

A. 18.6ml
B. 22.2ml
C. 30.4ml
D. 45.3ml

Green strength with reference to plaster means______?

A. Dry strength
B. Compressive strength
C. Strength of dental stone due to green colour
D. The wet strength

Water powder ratio of dental stone and plaster is respectively_______?

A. 0.28 and 0.6
B. 0.6 and 0.28
C. 0.6 and 3.2
D. 0.28 and 0.98

Model plaster (white) used to cast study models before mixing with water, is largely composed of_____?

A. CaO
B. CaCO₃
C. (CaSO4)₂-½H2O
D. CaSO4-2H₂O

White gold alloy predominantly is______?

A. Gold added with palladium
B. Gold added with calcium
C. Gold with much of chromium
D. Gold with silver

In type II gold alloys _______ Karat gold is used?

A. 24 K
B. 22 K
C. 18 K
D. 10 K

The material used in its pure form in dentistry is_______?

A. Composite
B. Silver
C. Gold
D. Amalgam

Cohesion of gold foil is an example of_______?

A. Atomic attraction and welding
B. Annealing
C. Wedging
D. Adaptation

Average particle size of powdered gold is______?

A. 10 um
B. 15 um
C. 30 um
D. 0.1 um

The pure form of gold used in dentistry is known as_______?

A. Cohesive gold
B. Non cohesive gold
C. Class I casting gold
D. Class IV casting gold

Electralloy is an alloy of______?

A. Gold and Platinum
B. Cobalt and Chromium
C. Gold and Calcium
D. Tin and chromium

The carat for Au foil used for restorations is_______?

A. 18
B. 20
C. 22
D. 24

Direct filling gold formed by electrolytic precipitation is called by all the terms EXCEPT______?

A. Crystalline
B. Granular gold
C. Mat gold
D. Sponge gold

When Gold fused with porcelain is fired at very high temperature greenish discoloration of cervical margin is due to______?

A. High firing temperature
B. Disintegration of opaque layer
C. Presence of copper
D. Formation of excess oxides

Powdered gold is______?

A. Made by a combination of chemical precipitation and atomization
B. Made by electrolytic precipitation
C. Made by beating pure gold at high temperatures
D. Made by milling pure gold ingots

Which of the following is true about direct filling gold_____?

A. Properly condensed mat gold has no voids
B. Whatever may be the type voids are inherent
C. Voids can be avoided with manual condensation
D. None of the above

The malleating force is directed______?

A. Perpendicular to the walls
B. Parallel to long axis of crown
C. 45° to the wall
D. None of the above

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Dental Material MCQs are most important for the examination related to dental jobs and all competitive examinations. 

Pitting of direct filling old restoration usually results from_______?

A. Using contaminated gold foil
B. Poor finished preparation
C. Improper stepping of condenser point
D. Using small condenser point

The cohesive gold used as bulk filler is_____?

A. Electra alloy
B. Mat gold
C. Spherical gold
D. Gold foll

Chemical tempering in porcelains is done to interrupt crack propagation by_____?

A. Transformation toughening
B. Dispersion of crystalline phase
C. Inducing residual compressive strength
D. All of the above

To prevent porosity in dental porcelain it should be backed_______?

A. Boric oxide
B. In vacuum
C. For long period
D. Under pressure

Pyroplastic flow of porcelain is due to_______?

A. High temperature during glazing
B. Low temperature during glazing
C. Improper condensation
D. High firing temperature

Condensation shrinkage of porcelain during firing depends on________?

A. Rate of arriving at firing temperature
B. Uniformity of particle size
C. Shape and size of particle
D. Type of investment used

Porcelain is best fired_________?

A. In open air
B. Under air compression
C. When several layer are fired simultaneously
D. Under minimum pressure

Porosity in porcelain can be prevented by______?

A. Thoroughness of condensation
B. Rapidity of firing
C. High firing temperature
D. All of the above

Which of the following is the main constituent of porcelain_______?

A. Feldspar
B. Kaolin
C. Quartz
D. Clay

The best tissue tolerated material for crown and bridge___?

A. Highly polished porcelain
B. Highly polished acrylic
C. Highly glazed porcelain
D. Highly polished metal

Dental porcelains are crystalline materials of_______?

A. Rubber
B. Plastic
C. Organic substances
D. Glass

The main purpose of adding metallic oxides in ceramic is_______?

A. Colour matching
B. Transparency
C. Opacity
D. None of the above

Coefficient of thermal expansion of metal-ceramic alloys is_____?

A. Same as porcelain
B. More than porcelain
C. Less than porcelain
D. More than or equal to porcelain but not less

Stage recognized in the firing of dental porcelain given below. Which of state is not correct ?

A. Cold stage bisque
B. Low bisque
C. Medium bisque
D. High bisque

The maximum shrinkage during firing process in ceramic occurs in________?

A. High Bisque stage
B. Low Bisque stage
C. Medium Bisque stage
D. Fusion stage

Super abrasive is________?

A. Sand
B. Silicon arbide
C. Diamond
D. Aluminum oxide

The preferred material for repair of fractured denture base is_______?

A. Chemically cure resin
B. Heat curve resin
C. Light cure resin
D. Vinyl resin

Dispersion of crystalline phase to strengthen ceramics results in________?

A. dispersed porcelain
B. Glazed porcelain
C. aluminium porcelain
D. All of the above

For porcelain fused to metal crown, the porcelain should have _______?

A. High fusion expansion
B. High fusion temperature
C. Linear coefficient of thermal expansion less than that of metal
D. Linear coefficient of thermal expansion more than that of metal

The ideal temperature of water bath for softening fluid wax is about_______?

A. 51 to 54 degree F
B. 51 to 54 degree C
C. 70 to 75 degree F
D. 70 to 75 degree C

Crocus cloth is______?

A. Emery
B. Garnet
C. Pumice
D. Rouge

The most toxic form of mercury is______?

A. Methyl and ethyl mercury
B. Mercury vapour
C. Inorganic mercury forms
D. Mercury sulphide

Ceramics fired to metals are processed by______?

A. Heat pressing
B. Machining
C. Sintering
D. Slip casting

When porcelain is basked against metal, it should possess a______?

A. high fusion expansion
B. high fusion temperature
C. linear coefficient of thermal expansion less than but close to that of metal
D. Linear coefficient of thermal expansion greater than, but close to that of the metal

Clogging of an abrasive wheel with debris causing reduction of abrasive action is called_____?

A. Blinding
B. Buffing
C. Dressing
D. Truing

Which of the following releases single wavelength of energy ?

A. QTH
B. PAC
C. LED
D. Argon lasers

The melting point of titanium is _____ degree Celsius?

A. 1056
B. 1560
C. 1668
D. 1886

Electrolyte used for plating copper dies is________?

A. Ionic copper
B. Copper cyanide
C. Silver cyanide
D. Acidic copper sulphate

Greening occurring when porcelains are fired on silver free alloys may be attributed to_____?

A. Vaporization of silver from the walls of contaminated furnaces
B. Surface diffusion of silver from the marginal metal
C. More rapid silver diffusion in sodium containing glass
D. Silver ionization by porcelains with high oxygen potential

Compared with dental alloys, CERAMICS show_______?

A. High ductility
B. High hardness
C. Low esthetic value
D. Susceptibility to brittle fracture

Chemical method of strengthening porcelain involves______?

A. Exchange of aluminum and sodium ions
B. Exchange of aluminum and potassium ions
C. Exchange of sodium and potassium ions
D. None of the above

The first porcelain tooth material was introduced by______?

A. DeChemant
B. Ash
C. Plateau
D. McClean

Which of the following bur is used in the preparation of cavity restored with porcelain fused to metal ?

A. Carbide bur
B. Diamond bur
C. Stainless steel bur
D. Diamond but for porcelain and carbide bur for metal

Quartz is Dental porcelain is_______?

A. Strengthener
B. Binder
C. Pigment
D. Crack minimzer

In method of firing: A shorter firing period at a higher temperature is considered better_____?

A. A large time period at a lower temperature is preferred
B. A long firing period at a very high temperature is preferred
C. A short firing period at a very low temperature is preferred
D. none of these

Porcelain binds to metal in PFM crown by_______?

A. Metallic bind
B. Transparency
C. Chemical bond
D. B and C

Dicer restoration is________?

A. Two coloured restorations
B. Heat pressed ceramics
C. Castabel ceramic
D. None of the above

Opaque porcelain_______?

A. Is Feldspathic glass
B. Contains opacifier like zirconium and titanium oxide
C. Not used to mask the colour of the cement used in placing of restoration
D. Used to produce the characteristic translucence, which is an inherent aspect of the incisal edge in natural teeth

Flux used in dental ceramic is______?

A. Alumina
B. Silica
C. Kaolin
D. Boric oxide

Which is not present in porcelain______?

A. Silica
B. Feldspar
C. Calcium carbonate
D. Amorphous material

Machineable glass ceramic is______?

A. Cerestore
B. Decor MGC
C. Infusium
D. Leucite

Phenomenon in which porcelain appears different under varying light condition is______?

A. Translucency
B. Refractive optics
C. Metamerism
D. Opacification

In porcelain metal elements are embedded in the matrix of______?

A. Rubber matrix
B. Glass
C. Plastic
D. Resin matrix

Porosity in porcelain at condensation stage depends on________?

A. Shape and size of particle
B. Uniform distribution of particle size
C. Number of particles
D. None of the above

The opacity in ceramics is achieved by adding_____?

A. Boric oxide
B. Copper oxide
C. Silica
D. Titanium oxide

Porcelain denture teeth______?

A. Have a higher coefficient of thermal expansion than acrylic teeth:
B. Have a lower abrasion resistance than enamel
C. Should be used where the inter dental clearance is small
D. Have a higher abrasion resistance than gold

Glass ionomer cements are composed of_____?

A. Alumino silicate powder and phosphoric acid
B. Aluminosillicate powder and polyacrylate
C. Zinc oxide powder and phosphoric acid
D. Zinc oxide powder and polyacrylate liquid

Minimum thickness for type I zinc phosphate cement should be______?

A. 15 microns
B. 25 microns
C. 50 microns
D. 100 microns

Which of the following is common to both zinc eugenol cement and polycarboxylate cement?

A. Polyacrylic acid is liquid
B. Chemical bond to tooth structure
C. Chelation
D. Substitution o eugenol by EBA to increase strength of cement

The addition of which of the following can accelerate the setting time of zinc oxide cement____?

A. Zinc acetate
B. Barium sulphate
C. Zinc sulphate
D. Barium chloride

pH of fully set zinc phosphate______?

A. 3-4
B. 4-5
C. 6-7
D. 7-8

Which of the following cements is most irritant to pulpal tissues ?

A. Zinc phosphate
B. Silicate
C. Glass ionomer
D. Polycarboxylate

PH of polycarboxylate liquid is_____?

A. 5
B. 7
C. 8
D. 1.7

When selection the colour of cement to use for cementing a porcelain jacket crown, the powder being tested is best mixed with______?

A. Glycerin-water solution
B. Cement liquid
C. Alcohol
D. Only water

The setting of zinc phosphate may be retarded by ?

A. Increased in the ratio of powder to liquid
B. Diluting the liquid with water
C. Increase the addition of powder to liquid
D. Decrease the addition of powder to liquid

Thickness of luting cement is_____?

A. 20-40μ
B. 10-20μ
C. 60-80μ
D. 1-2μ

The chief advantage of zinc phosphate cement is its_____?

A. Good compressive strength
B. Film thickness
C. Lack of irritation
D. Low solubility

Which of the following cements is most biocompatible with pulp ?

A. GIC
B. Copper cement
C. Zinc phosphate cement
D. Zinc oxide eugenol cement

The major component of zinc phosphate cement is______?

A. Zinc oxide
B. Phosphoric acid
C. Zinc
D. None of the above

Polycarboxylate cement is used for____?

A. Temporary restoration
B. Leuting
C. Permanent restoration
D. Die material

The dual cure cements should not be used with light transmitting prostheses thicker than____________?

A. mm
B. 1.5 mm
C. mm
D. 2.5 mm

Which of the following is most important in strength ZOE____?

A. Liquid powder ratio
B. Temperature of mixing stab
C. Speed of mixing
D. Addition of few drops of water

The effect of zinc oxide-eugenol on the pulp ?

A. Is irritating
B. Encourages pulpal fibrosis
C. Is sedating
D. Has no effect

Best marginal seal is provided by______?

A. Zinc phosphate
B. Zinc oxide eugenol
C. Gutta-percha
D. Resin

Secondary caries is least likely seen with______?

A. Silicate cement
B. Zinc phosphate
C. Polycarboxylate
D. GIC

Most preferable cement for temporary restoration______?

A. GIC
B. ZOE
C. Ca (OH)2
D. Zinc polycarboxylate cement

Why GIC is best restorative material in children_______?

A. High strength
B. Good marginal integrity
C. It can bond enamel & dentin
D. It has less occlusal wear

The setting of zinc phosphate is accelerated by______?

A. Adding a drop of water
B. Increasing mixing time
C. Cooling the slab
D. Adding a drop of oleic acid

PH of which cement remain below 7 even after 1 month after insertion into the cavity ?

A. Glass Ionomer Cement
B. Zinc Phosphate
C. Resin cement
D. Silicate cement

The most commonly used, most biocompatible and adhesive cement is______?

A. Zinc phosphate
B. Zinc oxide eugenol
C. Calcium hydroxide
D. Glass ionomer

Torsional force is_______?

A. Compression
B. Tensile force
C. Shear
D. Transverse bending force

All of the following is used as accelerator in zinc oxide eugenol cement except_______?

A. Acetic acid
B. Zinc acetate dehydrate
C. Calcium chloride
D. Bromoglycerine

The principal constituent of set silicate cement matrix is______?

A. Hydrated Aluminium phosphate
B. Hydrated Aluminium Phosphate with calcium fluoride
C. Hydrate Aluminosilicate gel
D. Hydrated Aluminium phosphate crystal, CAF2 alluminosiliate gel

Age hardening is a process done at_____?

A. Heating up to 200 – 450°C for 15 – 30 min and quenching in water
B. Heating at 700°C for 10 – 15 min and quenching in water
C. Heating at 700°C for 1 hour and quenching in water
D. Heating above 700°C for 30 min and quenching in water

Frozen slab technique is applicable to______?

A. Zinc phosphate cement
B. Glass Ionomer cement
C. Zinc oxide Eugenol cement
D. Resin cement

Which of the following acts as accelerator in Zinc oxide eugenol______?

A. ZnCl2 + Eugenol
B. ZnCl2 + ZnSO2
C. Eugenol + ZnO
D. Zn(OH)2 + ZnO

Strength of zinc phosphate is effected by______?

A. Temp of glass slab
B. P:L ratio
C. Consistency of mix
D. Alteration of mixing time

Frozen slab technique of mixing zinc phosphate is used for_____?

A. Cementing crowns
B. Temporary dressing
C. base
D. cementing orthodontic bands

About zinc oxide eugenol all are true except_____?

A. ZnO is converted to Zn(OH)2
B. Reaction is autocatalytic
C. Water is the byproduct of reaction
D. Dehydrated ZnO reacts with dehydrated eugenol

Which glass ionomer cement develops early resistance to water intake on setting ?

A. Reinforced auto care glass ionomer cement
B. Compomer
C. Resin modified glass ionomer cement
D. Ceramic reinforced glass ionomer cement

All of the following statements are true for zinc oxide eugenol cements except_____?

A. Equal lengths of base paste and accelerator paste are mixed together until the mix has a uniform colour
B. Increase in temperature and humidity shorten the setting time
C. The mix appear thick at the start of mixing but after 30 seconds of additional spatulation it becomes more fluid
D. Water accelerates but heat retards the setting of zinc oxide eugenol cements
E. Both C & D

Advantage of zinc phosphate over GIC is_______?

A. High compressive strength
B. Tensile strength
C. High modulus of elasticity
D. Diametral strength

Cavity varnishes have_____?

A. Average bonding to tooth
B. Low bonding to tooth
C. Excellent bonding to tooth
D. No bonding to tooth

Which one of the following dental cements does not contain water as part of the composition of the liquid component ?

A. Zinc Phosphate cement
B. Zinc oxide equgenol cement
C. Zinc silicophosphate cement
D. Zinc polycarboxylate cement

Which one of the following restorative materials is having coefficient of thermal expansion close to that of tooth enamel and dentin ?

A. Microfilled composite resins
B. Pure gold
C. Silver amalgam
D. Type II Glass ionomer cement

Mode of failure during dislodgement of prosthesis cemented with zinc poly carboxylate cement is usually seen at the____?

A. Cement tooth interface
B. Cement prosthesis interface
C. Cleavage through the cement layer
D. Fracture of tooth or prosthesis

The setting time of ZnPO4 cement can be retarded by____?

A. mixing more powder to the liquid
B. mixing powder to liquid, checked by water
C. slower addition of powder to liquid
D. faster addition of powder to liquid

MEchanism of adhesion of GIC restoration with tooth surface is by mean of ______?

A. Carboxyl group
B. Chelates with Metal Ions
C. C=C double bond
D. Polymer chains

In non-eugenol pastes the constituents are mixed in______?

A. Phosphoric Acid
B. Ethyl alcohol
C. Benzoic acid
D. None of the above

Ethoxy benzoic acid increases the strength and solubility of the cement______?

A. Zinc oxide eugenol
B. Polycarboxylate cement
C. Zinc phosphate cement
D. Silicate cement

Which cement base has the highest modulus of elasticity ?

A. Zinc polycarboxylate
B. Polymer reinforced ZOE cement
C. Zinc phosphate
D. Glass inomer cement

The cavity varnish applied reduces post operative sensitivity in amalgam restoration by______?

A. Decreasing conduction of heat to pulp
B. Minimize marginal leakage around restoration
C. By altering the chemical composition of restoration materials
D. By preventing penetration of corrosion products into the dentinal tubules

The average life of silicate cement restoration is______?

A. 2 years
B. 4 years
C. 6 years
D. 8 years

All of the following are true for traditional solution liner, except______?

A. It is not necessary in moderately deep cavities under glass ionomer restoration
B. Have Film thickness of 1 – 50 microns
C. Do not provide thermal or electric insulation
D. Protect the pulp from reaction products leaching out of restoration

Which of the following cements bonds to tooth structure, which has an anticariogenic effect, has a degree of translucency and does not irritate the pulp ?

A. Polycarboxylate cement
B. Resin cement
C. Silicate cement
D. Glass ionomer cement

Which of the following characterizes the silicate cement____?

A. It is pulpal irritant
B. It is highly cariogenic
C. Chemically attaches to the tooth structure
D. It produces thinnest film surface

Which of the following cements have anti cariogenic properly_______?

A. ZOE
B. Calcium Hydroxide
C. Zinc silicophosphate
D. Zinc phosphate

The principle application of zinc phosphate cement is______?

A. In final cementation
B. As temporary cementation
C. As a temporary filling material
D. It has less occlusal wear

Which of the following cements is contraindicated in mouth breathers_______?

A. Silicate
B. ASPA
C. Polycarboxylate
D. Zinc phosphate

Percentage of zinc in ZOE cement is______?

A. 60%
B. 70%
C. 80%
D. 90%

The main components is sillicophosphate cement______?

A. Zinc phosphate and GIC
B. Silicate and GIC
C. ZOE and Silicate
D. Zinc phosphate and SIlicate

Which component of zinc oxide-eugenol cement gives its strength ?

A. Rosin
B. Zinc oxide
C. Zinc acetate
D. Oil of cloves

Which cement is irritating to the pulp ?

A. Carboxylate cement
B. Zinc oxide-eugenol cement
C. Zinc phosphate
D. Ethoxybenzoic acid

The cement Which is least soluble in oral cavity_____?

A. Glass ionomer
B. Resin cement
C. Polycarboxylate cement
D. Silico-Phosphate cement

Silicate cement is indicated in______?

A. Mouth breathers
B. Patients with high caries index
C. In the restoration of posterior tooth
D. None of the above

Which of the following cements is most kind to pulp ?

A. Glass ionomer
B. Polycarboxylate
C. Silicate
D. Resin cement

What is the working time of zinc polyacrylate cement ?

A. 1 Minutes
B. 2 Minutes
C. 3 Minutes
D. 4 Minutes

All of the following is used as accelerator in zinc oxide eugenol cement except______?

A. Acetic acid
B. Zinc acetate dehydrate
C. Calcium chloride
D. Bromoglycerine

The tow cements which hold with the tooth are______?

A. GIC and polycarboxylate
B. GIC and ZnPO4
C. ZnPO4 and silicate
D. GIC and silicate

The logical explanation for the unique anticariogenic property of most silicate cements is____?

A. The reduction in enamel solubility due to fluoride uptake by enamel
B. That beryllium flux is used in silicates
C. That silicates show very little leakage at the margins of the restoration
D. Due to the high silica content

Thermal conductivity of which material is close to dentin____?

A. Amalgam
B. Silicate
C. Composite resin
D. Cavity varnish

Eugenol may be replaced in the zinc oxide eugenol cement by_____?

A. Acetic acid
B. Alginic acid
C. Phosphoric acid
D. Ortho-ethoxy acid

Which is the cement with adhesive properties ?

A. Zinc oxide eugenol
B. Zinc polycarboxylate
C. SIlicate
D. Glass ionomer
E. Both B & D

Which of the following do polycarboxylate and GIC have in common ?

A. Polysiloxane
B. Phosphoric acid
C. Polyacrylic acid
D. Ion leachable glass

Which of the following show chemical bond with enamel (Calcified tissues)__ __?

A. Composites
B. Direct filling resins
C. Polycarboxylate cements
D. BIS-GMA resins in pit and fissure sealants

Increased amount of powder in zinc phosphate cement mixture will cause_____?

A. Decreased strength
B. Decreased film thickness
C. Decreased solubility
D. Increased setting time

The temperature (in °F) of the mixing slab for silicate cements should be_____?

A. 55 – 65
B. 65 – 75
C. 75 – 85
D. 85 – 95

Which one of the following dental cement accelerates the formation of reparative dentin ?

A. Eugenol
B. Calcium Hydroxide
C. Zinc oxide
D. Silica

Fluoride rich materials include ?

A. Silicate cement
B. Glass ionomer cement
C. Polycarboxylate cement
D. All of the above

Dynamic creep is the______?

A. Continuing alloying between silver-tin alloy and mercury during the life of restoration
B. Deformation of set amalgam during function
C. Process whereby alloy is wetted by mercury
D. Spread of amalgam during packing

The dental amalgam is most resistant to______?

A. Compressive stress
B. Impact stress
C. Shear stress
D. Tensile stress

According of ADA specification No or number 1, the minimum compressive strength for silver amalgam filling after one hour should be______?

A. 80 Mpa
B. 140 Mpa
C. 260 Mpa
D. 510 Mpa

Admixed high copper alloy powder contains______?

A. 9-20% copper
B. 13-20% copper
C. 9-30% copper
D. 13-30% copper

Finishing and polishing of Amalgam make the restoration______?

A. Increase in tarnish and corrosion resistance
B. Increase the marginal strength
C. Decrease the tarnish and corrosion resistance
D. Increased compressive strength

Setting time of Amalgam is best controlled by ______?

A. Using spherical particles
B. Lathe cut alloy
C. Altering Hg-Alloy ratio
D. Trituration time

In non zinc containing dental amalgam alloy the percentage of zinc present is_____?

A. Less than 0.02%
B. Less than 0.1%
C. Less than 0.01%
D. None of the above

High copper dental amalgams are superior to other amalgams because high copper dental amalgems_____?

A. Have less marginal breakdown
B. Are workable at lower Hg-alloy ratio
C. Have a higher ratio of tensile to compressive strength
D. Have less resistance to tarnish and corrosion

The largest component of amalgam alloy is_______?

A. Silver
B. Tin
C. Zinc
D. Copper

During amalgamation, trituration is done to____?

A. Dissolve the alloy in mercury
B. Coat the alloy particle with mercury
C. Remove excess mercury from the amalgam
D. Dissolve Hg in alloy

Dental Material MCQs- Past papers

Past papers related to the dental material are given for the preparation of Short Service Regular Commission in Pakistan Army to become Captain or Major in the medical field. 

Amalgam restorations give the best clinical service when the residual mercury content is___?

A. 38-42%
B. 48-52%
C. 58-62%
D. 68-72%

Percentage of tin in low copper alloy is_____?

A. 30-35%
B. 26-28%
C. 13-32%
D. 22-30%

Cause of expansion in zinc containing amalgam is_____?

A. Zinc and water
B. Water
C. Hydrogen
D. Nascent oxygen

What is common in amalgam and ceramics ?

A. More compressive strength but less tensile strength
B. More compressive strength and tensile strength
C. Less compressive strength but more tensile strength
D. Less compressive strength and tensile strength

Which of the following constituents of amalgam alloy decreases expansion_____?

A. Copper
B. Zinc
C. Silver
D. Tin

The higher the Hg alloy ratio in dental amalgam_______?

A. Higher the strength
B. Lower the creep value
C. More matrix matrial formed
D. More gamma 1 phase formed

Ag-Cu eutectic alloy has a characteristic Property of that fusion temp of_______?

A. The resultant alloy is greater
B. The resultant alloy is lesser
C. The resultant alloy varies according to the content of Ag of Cu
D. None of the above

What is the recommended for condensation of dental amalgam ?

A. 35 pounds
B. 3 pounds
C. 15 lb
D. 25 lb

Which is not true about high copper amalgam alloys_____?

A. Low tensile and compressive strength
B. Low Hg: Alloy ratio
C. High tensile strength
D. Low creep

Amalgam means______?

A. A metallic powder composed of silver, tin, copper and zinc
B. An alloy of two or more metals one of which is mercury
C. An alloy of two or more metals that have been dissolved in each other in the molten state
D. A metallic substances in powder or tablet from that is mixed with mercury

In amalgam alloy which acts as oxygen scavenger______?

A. Cu
B. Zn
C. Pd
D. Ag

By increasing the percentage of which metal, the strength and hardness of amalgam increases____?

A. Ag
B. Zn
C. Cu
D. Hg

Which of the following statement is true regarding lathe cut low Copper silver alloy ?

A. Requires least amount of mercury
B. Achieves high compressive strength at 1 hr.
C. Has tensile strength both at 15 minutes and 7 days is comparable to high copper, unicompositional alloys
D. Has lower cree value

Creep value of which of the following is the highest ?

A. Low copper amalgam alloy
B. Admix alloy
C. Single composition alloys
D. Creep value of all the above mentioned alloys is same

Amalgam achieves 70% of the strength by_____?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours

Amalgam achieves 70% of the strength by_______?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours

Mercury is toxic because it_____?

A. Complexes with hemoglobin to form methemoglobin
B. Inhibits hemoglobin synthesis, producing anemia
C. Inhibits anaerobic glycolysis
D. Binds to sulfhydryl groups

What fraction of inhaled mercury vapors retained in the body ?

A. 45-55%
B. 55-65%
C. 65-85%
D. More than 85%

The effect of trituration on strength in an amalgam restoration depends on_____?

A. Amalgam alloy
B. Trituration time
C. Speed of amalgamator
D. All of the above

Decrease in creep occurs in______?

A. Under trituration or over trituration of amalgam
B. Decreases with condensation pressure
C. Increase with condensation pressure
D. Cannot be predictable

Cavo surface angle for amalgam restoration is butt joint as_______?

A. It increases compressive and tensile strengths
B. Decreased compressive, increased strength
C. Decreased compressive, decrease tensile strength
D. Increased compressive, increased tensile strength

Which of the following are characteristic feature of high copper amalgam alloy ?

A. Low compressive strength
B. High marginal breakdown
C. Less marginal #
D. High creep

Co-efficient of Thermal expansion of amalgam is_____?

A. 6.6 a (ppm k-1)
B. 11.4 a (ppm k-1)
C. 14.0 a (ppm k-1)
D. 25.0 a (ppm k-1)

A patient who has had a recent amalgam filling in the upper teeth has a gold filling in the lower teeth, the patient complains of pain. The reason for this can be mainly____?

A. Improper amalgam filling
B. Pulp exposure
C. Galvanism
D. None of the above

Outstanding clinical performance of dental amalgam restoration is related to its______?

A. Compressive strength
B. Tensile strength
C. Corrosion
D. Creep

Absorption of mercury in the human body occurs least from______?

A. Lungs
B. Gastro-intestinal Track
C. Skin
D. Kidneys

High copper amalgam can be produced_______?

A. From smooth atomized particles
B. From irregular and spherical particles
C. From lathe cut particles
D. From traditional alloy particles

Which one of the following is not an objective of trituration ?

A. Remove oxides from powder particle surface
B. Keep the amount of gamma-1 or gamma-2 matrix crystals to maximum
C. Pulverize pelletes into particles to aid in attack by mercury
D. Achieve a workable mass of amalgam in minimum time

Gallium and indium added to Amalgam replace_____?

A. Silver
B. Tin
C. Mercury
D. Zinc

Which is true regarding lathe cut silver alloy____?

A. Requires least amount of mercury
B. Achieves lowest compressive strength at 1 hr.
C. Has tensile strength both at 15 min & 7 days comparable to high copper unicompositional alloy
D. Has low creep

Adequate mixing of mercury is indicated by___?

A. Dry Mix
B. Shiny Mix
C. Short Mixing Time
D. None of the above

For dental amalgam, the elastic modulus and tensile strength is______?

A. 40 Gpa and 60 – 100 Mpa
B. 21 Gpa and 27 – 55 Mpa
C. 350 Gpa and 10 – 120 Mpa
D. 360 Gpa and 125 – 130 Mpa

Which of the following does not occur in High Copper Amalgam ?

A. Electrochemical Corrosion
B. Chemical Corrosion
C. Penetrating Corrosion
D. Corrosion does not occur at all

High strength amalgam is achieved by_____?

A. Maximum matrix and minimum alloy phase
B. Minimum matrix and maximum alloy phase
C. Maximum matrix phase
D. Minimum alloy phase

Once triturated, the Dental amalgam should be condensed with in______?

A. 5 minutes
B. 6 minutes
C. 3 minutes
D. 15 minutes

The solid solution of silver and mercury is called_____?

A. y1
B. y2
C. B1
D. y

Advantage of minimum mercury technique or Eames technique is all Except______?

A. High strength
B. Sets quickly
C. Needs no squeezing of excess mercury
D. Greater plasticity and adapts well to cavity walls

Mercury rich condition in a slow setting amalgam alloy system in a restoration in_____?

A. Accelerated corrosion
B. Fracture of the restoration
C. Merginal damage
D. All of the above

Over-trituration of silver alloy and mercury______?

A. Reduces contraction
B. Increases the strength of lathe cut alloy but reduces the strength of spherical alloy amalgam
C. Decreases creep
D. Gives al dull and crumbly amalgam

Mercury intoxication in dental office mainly results from_______?

A. Direct contact with the mercury
B. Inhalation of mercury vapours
C. Ingestion of mercury
D. None of the above

The threshold limit value of mercury exposures is______?

A. mg / m3
B. 0.05 mg / m3
C. mg / m3
D. mg / m3

The tarnished layer of silver amalgam consists of______?

A. Sulphides of silver
B. Oxides of tin
C. Chlorides of tin
D. All of the above

Which phase provides maximum strength in hardened mercury/silver alloy ?

A. Silver / Mercury phase
B. Silver / Tin phase
C. Tin / Mercury phase
D. Zinc / Mercury phase

Copper content in low copper amalgam is_______?

A. 6%
B. 12-30%
C. 29%
D. 19%

Which of the following silver amalgam alloy have the maximum strength______?

A. Lathe cut
B. Spherical
C. Admixed
D. Single composition

What is the most frequently used restorative material ?

A. Silicate
B. Amalgam
C. Composite
D. Gold

How soon after a moisture contamination does a zinc containing amalgam alloy start expanding______?

A. 24 hours
B. 1-2 days
C. 3-5 days
D. 7 days

The percentage of copper in high copper alloy is_____?

A. 10-12%
B. 0-6%
C. 13-30%
D. 20-30%

What is the working time of amalgam?

A. One to two minutes
B. Three to four minutes
C. Five to six minutes
D. Seven to eight minutes

Advantage of zinc containing amalgam is_______?

A. Better handling property
B. Dimensional Stability
C. Resistance to creep
D. Toxicity to pulp and dentin

Discoloration of silver alloy is due to_____?

A. Tarnish
B. Tarnish and corrosion
C. Wet corrosion
D. Dry corrosion

Moisture contamination of amalgam can lead to____?

A. Marginal breakdown
B. Shrinkage
C. Delayed expansion
D. increased stresses

In a high copper amalgam the phase, which is eliminated is______?

A. Gamma 1
B. Gamma 2
C. Gamma 1 and 2
D. No phase is eliminated

Well premeasured capsules of amalgam can release mercury vapour during_____?

A. Mulling
B. Carving
C. Condensation
D. Trituration

In spherical alloys as compared to lathe cut______?

A. Less condensing force is required
B. More condensing force is required
C. Both require same condensing force
D. Manipulation is easy

Chronic mercury toxicity results from_____?

A. Ingestion while removing old amalgam
B. Skin contact
C. Mercury vapour
D. All of the above

Increase in the residual mercury in silver amalgam filling can_____?

A. Cause fracture of the filling
B. Tarnish and corrosion
C. Increase the strength
D. Decrease condensation pressure

Which of the following statements about high copper silver alloy compared to conventional alloy is not true ?

A. It has increased tensile and compressive strength
B. It has poor tarnish and corrosion resistance
C. It’s edge strength is greater
D. Mercury content in the final restoration is less

Compare to conventional amalgams, spherical amalgams_____?

A. Require more mercury
B. Require heavy compection forces
C. Have longer setting times
D. None of the above

Which of the following phases of dental amalgam has minimum strength_____?

A. Gamma 1
B. Gamma 2
C. Epsilon 1
D. Gamma 3

The ADA specification No 1 for composition of amalgam alloy recommends_____?

A. 65% silver, 32% tin and 3% copper
B. 49% silver, 32% tin and 19% cooper
C. 65% silver, 29% tin and 5-6% copper
D. None of the above

The highest mercury concentration in amalgam filling is found______?

A. At the margin of the restoration
B. In the centre of the restoration
C. In the deepest part of the restoration
D. None of the above

The term trituration means_____?

A. Lysing amalgam alloy
B. Mixing of amalgam alloy and mercury
C. Removal of excess of mercury
D. None of the above

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