Free Polymers in Dentistry MCQs with Answers

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

Explanation: Acrylic resins are used for denture bases, provisional crowns and bridges, and some anterior restorative applications.

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

Explanation: Insufficient pressure during flask packing or curing allows monomer vapour and air spaces to remain in the denture base, producing…

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

Explanation: Glycol dimethacrylate acts as a bifunctional cross-linking agent, joining neighbouring polymer chains and improving resistance to crazing…

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

Explanation: Hydroquinone acts as an inhibitor, scavenging free radicals and preventing methyl methacrylate from polymerizing during storage.

• A. Methyl ethyl methacrylate
• B. Ethylmethacrylate
• C. Methacrylate
• D. Polymethylmethacrylate

Explanation: The liquid monomer in heat-cure denture-base resin is methyl methacrylate, which polymerizes to polymethyl methacrylate.

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

Explanation: Excess monomer increases the amount of liquid that must polymerize and therefore increases polymerization shrinkage.

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

Explanation: Benzoin methyl ether is a photoinitiator traditionally activated by ultraviolet light.

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

Explanation: Visible-light curing is a later denture-base processing method and uses light-activated resin rather than the conventional heat or…

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

Explanation: A controlled heating cycle prevents the monomer from boiling, which is the main cause of porosity in heat-cured acrylic resin.

• A. 6%
• B. 8%
• C. 10%
• D. 21%

Explanation: Although pure methyl methacrylate contracts by about 21% on polymerization, a 3:1 powder-to-liquid mix contains much less monomer…

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

Explanation: The repeating units of a dental resin polymer are joined by strong covalent bonds formed during polymerization.

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

Explanation: VLC means visible-light-cured, so VLC resins are activated by light rather than microwave energy, heat, or a purely chemical…

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

Explanation: Water sorption by cold-cure acrylic produces dimensional expansion, conventionally quoted as about 1% by volume and 0.23% by weight in…

• A. 25°C
• B. 37°C
• C. 50°C
• D. 60°C

Explanation: Benzoyl peroxide in heat-cured acrylic resin decomposes sufficiently to generate free radicals at approximately 60°C or above.

• A. 4:1
• B. 3:1
• C. 10:1
• D. 5:1

Explanation: A powder-to-liquid ratio of about 3:1 by volume gives the acrylic resin a workable dough suitable for packing.

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

Explanation: Copolymerization combines two or more different monomers so that the resulting polymer can combine useful properties from each monomer.

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

Explanation: Cross-linking joins polymer chains into a network that resists crack initiation and propagation, thereby improving craze resistance.

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

Explanation: Subsurface porosity in acrylic resin commonly results from overheating, which vaporizes monomer within the resin mass; the risk rises in…

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

Explanation: Packing acrylic resin in the sandy stage prevents proper adaptation and leaves interparticle spaces that become porosity after curing.

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

Explanation: Incomplete flask closure leaves excess resin or prevents complete seating of the trial closure, so the denture base and teeth remain…