All Free Dental Materials MCQs with Answers

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

Explanation: Torsion twists a material around its axis, producing shear stresses within it.

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

Explanation: Silicate cement has thermal conductivity closest to dentin among these choices.

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

Explanation: Dynamic creep is the time-dependent deformation of set amalgam under repeated functional loading.

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

Explanation: Mercury is toxic mainly because it binds to sulfhydryl groups on enzymes and proteins, disrupting cellular metabolism.

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

Explanation: Approximately 65% to 85% of inhaled elemental mercury vapour can be retained and absorbed, especially through the lungs.

• 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)

Explanation: Dental amalgam has a relatively high coefficient of thermal expansion, about 25 ppm/K, compared with tooth structure.

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

Explanation: The kidneys are a major target and storage site for absorbed mercury, not an important route by which mercury enters the body.

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

Explanation: Dental amalgam has an elastic modulus of roughly 21 GPa and a tensile strength commonly reported in the range of about 27 to 55 MPa.

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

Explanation: Inorganic filler particles reduce the resin matrix's thermal expansion, making the composite behave more like tooth structure and reducing…

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

Explanation: A dental composite is a resin matrix reinforced with filler particles, usually inorganic glass or ceramic.

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

Explanation: Light-cured composites use a diketone photosensitizer, commonly camphorquinone, with an amine co-initiator.

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

Explanation: A composite contains at least two distinct phases, such as a resin matrix reinforced with inorganic filler, so filled resin is the…

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

Explanation: The intense blue light used for curing composites can damage the retina, particularly with prolonged or unprotected exposure.

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

Explanation: Composite resin retention to etched enamel and dentin is mainly micromechanical: resin penetrates surface irregularities and forms resin…

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

Explanation: A plastic spatula is used for mixing composite because it reduces the risk of incorporating metal particles and avoids abrasion of the…

• 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

Explanation: Microfilled composites use extremely small colloidal silica particles, commonly about 0.01 to 0.1 microns.

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

Explanation: A composite combines two or more distinct materials, usually a resin matrix and inorganic filler, while retaining separate phases and…

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

Explanation: Composite resin is practically insoluble in oral fluids, whereas silicate cement is more vulnerable to oral-fluid dissolution.

• 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

Explanation: Acid etching produces microporosities, increases effective surface area, and improves wetting, allowing micromechanical retention.

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

Explanation: Microfilled composites provide the smoothest surface and best polish retention because their very small filler particles produce high…