Free Restorative Materials MCQs with Answers

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

Explanation: Potassium sulfate is the commonly used accelerator for gypsum and is often added at about 2%.

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

Explanation: The hygroscopic technique is used with gypsum-bonded investments to increase setting expansion while the material sets in contact with…

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

Explanation: A malleting force directed at about 45° to the wall helps condense direct filling gold against the wall without driving the material away…

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

Explanation: Pitting in an old direct gold restoration commonly results from improper stepping of the condenser, which leaves inadequately condensed…

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

Explanation: Mat gold is a cohesive gold form supplied as a bulk-like mass for building up a direct gold restoration.

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

Explanation: A water bath at about 51 to 54°C softens fluid wax uniformly without overheating or burning it.

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

Explanation: Copper dies are electroplated in an acidic copper sulphate electrolyte, which supplies copper ions for deposition.

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

Explanation: Silicate cement releases fluoride, which gives it a marked anticariogenic effect and historically made recurrent caries less common around…

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

Explanation: GIC chemically bonds to both enamel and dentin, allowing good retention in minimally prepared primary teeth.

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

Explanation: Cavity varnish is a thin resin film that seals dentinal tubules but does not chemically adhere to tooth structure.

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

Explanation: Type II glass ionomer cement has a coefficient of thermal expansion relatively close to that of enamel and dentin, reducing thermal…

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

Explanation: Amalgam withstands compressive forces well because its metallic mass resists crushing.

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

Explanation: ADA Specification No. 1 requires silver amalgam to develop a minimum compressive strength of about 80 MPa after one hour.

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

Explanation: Admixed high-copper amalgam powders contain approximately 9 to 20% copper, usually supplied as conventional silver-tin particles mixed…

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

Explanation: Finishing and polishing smooth the amalgam surface, removing rough areas that retain plaque and promote electrochemical attack.

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

Explanation: Trituration is the main clinical method for controlling amalgam’s setting time because it changes the extent and rate of mercury-alloy…

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

Explanation: A zinc-free amalgam alloy may contain only a trace amount of zinc, defined as less than 0.01%.

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

Explanation: High-copper amalgams eliminate or greatly reduce the weak gamma-2 phase, so they show less corrosion-related marginal breakdown.

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

Explanation: Silver is the largest component of conventional amalgam alloy powder by weight and contributes strength, resistance to corrosion and…

• 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

Explanation: During trituration, mercury wets and coats the alloy particles, allowing the surface elements to react and form the amalgam matrix.