Free Polymers in Dentistry MCQs with Answers

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

Explanation: Heat-cured methyl methacrylate uses benzoyl peroxide as its initiator; heating decomposes it into free radicals that start polymerization.

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

Explanation: Premature heating can raise the temperature of methyl methacrylate above its boiling point, producing gaseous porosity.

• 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

Explanation: Cross-linking requires monomers with two polymerizable functional groups, called difunctional or bifunctional monomers.

• A. Toluidine
• B. Quaternary ammonium compound
• C. Tertiary amineOral & Dental Care
• D. Benzoyl peroxide

Explanation: Tertiary amine activates benzoyl peroxide at room temperature to produce free radicals in self-cure acrylic resin.

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

Explanation: Polymethyl methacrylate acrylic resin was introduced as a denture-base material around 1937, replacing earlier materials such as…

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

Explanation: Properly heat-cured acrylic resin contains only about 0.2% to 0.5% residual free monomer.

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

Explanation: Insufficient flask pressure leaves excess resin or an inadequate closure during processing, increasing the denture’s vertical dimension.

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

Explanation: Unfilled methyl methacrylate can be polished to a smooth surface because it contains no abrasive filler particles that interfere with…

• A. Hydrophobic and hydrophilic component
• B. Only Hydrophilic component
• C. Only Hydrophobic component
• D. Lyophillic and lyophobic componentSource Raw Polymers

Explanation: Most dentin bonding systems combine a hydrophilic component to wet and infiltrate moist dentin with a hydrophobic component that bonds to…

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

Explanation: Self-curing resin polymerizes faster in hot water because increased temperature accelerates the decomposition of the initiator and the…

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

Explanation: Injection moulding does not require a separate trial closure because the resin is injected into the closed mould under pressure.

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

Explanation: Polymerization shrinkage is a major disadvantage of acrylic denture-base resin because it can cause dimensional change and loss of fit.

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

Explanation: Cold-cure acrylic polymerizes by a chemical initiator-activator system, but the reaction is still exothermic and releases heat.

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

Explanation: Dimethyl-p-toluidine is a tertiary amine accelerator used with benzoyl peroxide in chemically activated, or self-curing, acrylic resin.

• A. Porosity is uniformly distributed
• B. Thin Palatal area
• C. Thin area of flanges
• D. Hard thick central area

Explanation: Heating denture acrylic above the boiling point of its monomer produces gaseous monomer porosity, especially in the thick central portion…

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

Explanation: Self-cured acrylic has lower molecular weight, more residual monomer and greater porosity, so its transverse strength is lower than that…

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

Explanation: Montan wax is a mineral wax obtained from lignite or brown coal. Paraffin is derived from petroleum, whereas microcrystalline wax is also…

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

Explanation: Vulcanization converts a rubber-base polymer into an elastic, rubber-like material by forming cross-links between polymer chains.

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

Explanation: Chemically cured, or autopolymerizing, acrylic resin is preferred because it can polymerize directly at room temperature without heating…