MCQs on Dental Materials - Restorative Resins

 

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# 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

# In heat cure denture base acrylic resins the monomer is:
A. Methacrylate
B. Ethylmethacrylate
C. Methyl ethyl methacrylate
D. Polymethylmethacrylate

# If curing occurs at temperature more than 100°C porosity results in which area of denture?
A. Hard thick central area
B. Thin Palatal area
C. Thin area of flanges
D. Porosity is uniformly distributed



# Which of the following is an example of a composite material?
A. A filled resin
B. Colloidal silica
C. Gold alloy
D. Wax

# 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

# Which of the following initiator accelerator system uses light activation composite?
A. Diketone-amine
B. Organic acid-metal oxide
C. Organic acid-peroxide
D. Peroxide-amine

# Acrylic (cold cure)
A. Melts at 100°c
B. Softens at 100°c
C. Still requires heat for polymerization
D. Produces heat during polymerization

# Hydroquinone is added to methyl methacrylate monomer:
A. To prevent polymerization during storage
B. To initiate release of free radicals
C. To enable polymerization reaction at room tern perature
D. All of the above

# Radio opacity to composite resins is rendered by:
A. Silica glass
B. Organic matrix
C. Barium glass and strontium glasses
D. Fluoride particles

# Cross Linking in denture base resin is contributed by:
A. Glycol dimethacrylate
B. Benzoyl peroxide
C. N-Para toluidine
D. Methyl methacrylate

# The most important disadvantage of acrylic denture base is:
A. Porosity
B. Shrinkage
C. Tooth breakage
D. Water absorption

# 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

# 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

# Acrylic resins are used for:
A. Anterior restorations
B. Temporary bridges
C. Denture bases
D. All of the above

# 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

# 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

# In self-cure acrylic resin, activator is:
A. Toluidine
B. Quaternary ammonium compound
C. Benzoyl peroxide
D. Tertiary amine

# 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 resins in comparison to acrylic have:
A. Low compressive strength
B. High abrasive resistance
C. High water absorption
D. High polymerization shrinkage

# Composite has:
A. Resin
B. Filler
C. Resin and Filler
D. None

# 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

# Boiling point of methyl methacrylate:
A. > B.P of water
B. < B.P of water
C. Equal to BP of water
D. Is at normal room temperature

# Polymerisation of heat-cured methyl methacrylate is initiated by:
A. Tertiary amine
B. Benzoyl peroxide free radical
C. Hydroquinone
D. Methyl ether

# 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

# Subsurface porosity is due to:
A. Thermal changes
B. Thickness of the resin
C. Lack of temperature
D. Packing past the dough stage

# Light cure system, side effect is:
A. Iritis
B. Cataract
C. Conjunctivitis
D. Retinal damage

# 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

# Bonding of composite resins to tooth structure is by:
A. Covalent bond
B. Ionic bond
C. Mechanical
D. Vanderval forces

# Which one of the following is used as filler in composite resins?
A. Quartz
B. Silica
C. Zinc particles
D. Aluminium

# The type of spatula used to mix composite is:
A. Plastic
B. Stainless steel
C. Iron
D. None of the above

# The chemical used to etch enamel is:
A. Zinc oxide
B. Methyl methacrylate
C. Phosphoric acid
D. Eugenol

# 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

# 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 oif terminating agents

# 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

# 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 use
C. Will cure composite upto a depth of 5 millimeter thickness
D. Is fiber optic

# 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 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

# The imperfection seen on the lingual flange of a lower denture caused by rapid heating during a curing cycle is called:
A. Localised shrinkage porosity
B. Gas inclusion porosity
C. Micro-porosity
D. Surface porosity

# No trail closure is necessary with which one of the technique during denture fabrication:
A. Compression moulding technique
B. Injection moulding technique
C. Fluid resin technique
D. Light cured technique

# The particle size in microfilled composites is:
A. 0.02 to 0.04 mm
B. 0.5 to 1.0 microns
C. 0.01 to 0.1 microns
D. 0.3 to 0.4 mm

# A material which is a mixture of two different materials and its properties are:
A. Composite
B. Complex material
C. Combined
D. Compound

# Acid-etching is done for:
A. 30 Seconds
B. 60 seconds
C. 90 seconds
D. 120 seconds

# The polymerization of self-curing resin takes place faster in:
A. Cold water
B. Hot water
C. Under pressure
D. In vacuum

# Coefficient of thermal expansion is highest for:
A. Amalgam
B. Silicate cement
C. Gold alloy
D. Acrylic resin

# Which of the following provide opacity to composite?
A. TEGDMA
B. BIS-GMA
C. Ti02
D. None

# The latest method of curing denture base resins:
A. Heat
B. Visible light
C. Chemicals
D. Lasers

# Dentin bonding agents usually contain:
A. Only Hydrophobic component
B. Only Hydrophilic component
C. Hydrophobic and hydrophilic component
D. Lyophillic and lyophobic component

# 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

# The advantage of unfilled methyl methacrylate is that:
A. It can be finished smoothly
B. It has a low degree of flow
C. It is non-irritating to pulp
D. Its wear resistant is high

# 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

# 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

# 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

# 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

# For esthetic areas where high luster is required the restoration that is used usually:
A. Glass ionomer restoratives
B. Hybrid resin composites
C. Microfilled resin composites
D. Macrofilled resin composites

# 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

# Which of the following absorbs maximum amount of water?
A. Microfilled resin
B. Macrofilled resin
C. Hybrid
D. Small particle composites

# The percentage 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%

# The restoration which shows percolation and shrinkage along the margin is:
A. Composites
B. Unfilled resins
C. Amalgam
D. Polycarboxylate

# 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 commonly used laser for curing composite resin is:
A. Nd:YAG
B. CO2
C. Er:YAG
D. Argon

# 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

# What is the polymerization shrinkage if 3:1 powder: liquid ratio is used?
A. 6%
B. 8%
C. 10%
D. 21%

# Acrylic resins were first introduced as a denture base material in:
A. 1925
B. 1937
C. 1951
D. 1956

# Macromolecules in Dental Resin is attached by:
A. Covalent bonds
B. Sonic bonds
C. Vander Wall's Forces
D. Hydrogen Bonds

# Quartz tungsten light cure device, minimum output of energy should not be less than:
A. 300 mw/cm2
B. 350 mw/cm2
C. 400 mw/cm2
D. 450 mw/cm2

# 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

# Denture acrylics contain cross-linking agents, mainly to improve their:
A. Internal color
B. Tissue compatibility
C. Surface hardness
D. Craze resistance

# The most common coupling agents are organic silicon compounds called:
A. parabane
B. ligane
C. silane
D. chelane

# 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

# 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

# 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

# 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 resto rative material

# 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. 3% to 5%

# VLC resins are also called as:
A. Microwave-activated resins
B. Tertiary amine-activated resins
C. Light activated resins
D. Heat activated resins

# 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

# 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

# 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

# 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

# During polymerisation of acrylic resin, above what temperature benzoyl peroxide form free radicals:
A. 25° C
B. 37° C
C. 50° C
D. 60° C

# Etchant preferred in gel form 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

# An acidic agent that dissolves the in organic structure in dentin that allows infiltration of adhesive resin is:
A. Dentin bonding agent
B. Dentin conditioner
C. Primer
D. None of the above

# In acrylic restorative materials, the pumping action of alternately imbibing and excluding fluids is termed as:
A. lmbibition
B. Percolation
C. Syneresis
D. Evaporation

# What is the wave length of visible light used for curing light cure restoration?
A. 400 - 420 nm
B. 250 - 300 nm
C. 420 - 475 nm
D. 300 - 370 nm

# True about conversion of monomer to polymer is:
A. Density changes from 1.19g/cm3 to 0.9 and volume shrinkage is 21%
B. Density changes from 1.19g/cm3 to 0.9 and volume shrinkage is 7%
C. Density changes from 0.9g/cm3 to 1.19 and volume shrinkage is 21%
D. Density changes from 0.9g/cm3 to 1.19 and volume shrinkage is 7%

# According to ADA specification number 12, dough forming time should be less than ______ min. from the start of the mixture.
A. 90 min
B. 60 min
C. 50 min
D. 40 min

# Role of plasticizer in synthetic resins in dentistry is:
A. Increase smoothness
B. To increase bulk
C. To prevent polymerisation shrinkage
D. To reduce softening and fusion temperature

# Of the light produced by quartz - tungsten - halogen, only a small percentage is suitable for curing composite resin material and most is converted into heat. How much percentage of this light is useful for curing?
A. 0.5%
B. 5%
C. 10%
D. 50%

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