All Free Dental Materials MCQs with Answers

• A. Increase the strength and the setting expansion of the phosphate-bonded investment
• B. Is applied to the walls of the investment to produce hygroscopic expansion
• C. Acts as a retarder in the silica bonded investments
• D. Acts as a refractory in the Silica bonded investments

Explanation: Silica sol is the liquid component commonly used with phosphate-bonded investments, where it increases strength and contributes to setting…

• A. CaCl2
• B. Glycerine
• C. Alcohol
• D. Zinc acetate

Explanation: Glycerine acts as a retarder in zinc oxide eugenol by slowing the setting reaction.

• A. Olive oil
• B. Linseed oil
• C. Zinc acetate
• D. All of these

Explanation: Zinc acetate accelerates the setting of zinc oxide eugenol by promoting formation of the zinc eugenolate matrix.

• A. Cooling the glass slab
• B. Adding a drop of water
• C. Adding a drop of eugenol
• D. Altering ratio of two pastes

Explanation: Cooling the glass mixing slab slows the setting reaction of zinc oxide eugenol cement and provides practical control without altering its…

• A. Adding a small amount of glycerine
• B. Adding a small amount of water
• C. Altering the amounts of the two pastes used
• D. Cooling mixing slab

Explanation: A small amount of water generally accelerates the zinc oxide-eugenol reaction, whereas glycerine, a cooler slab, or altering the paste…

• A. Alumino silicate powder and phosphoric acid
• B. Zinc oxide powder and phosphoric acid
• C. Aluminosillicate powder and polyacrylate
• D. Zinc oxide powder and polyacrylate liquid

Explanation: Glass ionomer cement forms by reacting an aluminosilicate glass powder with an aqueous polyacrylic acid solution.

• A. 15 microns
• B. 25 microns
• C. 50 microns
• D. 100 microns

Explanation: Type I zinc phosphate cement is a luting cement whose required film thickness is approximately 25 micrometres or less.

• A. Polyacrylic acid is liquid
• B. Chemical bond to tooth structure
• C. Substitution o eugenol by EBA to increase strength of cement
• D. Chelation

Explanation: Both materials involve chelation: zinc eugenol cement forms zinc eugenolate, while polycarboxylate cement can chelate calcium in tooth…

• A. Zinc acetate
• B. Barium sulphate
• C. Zinc sulphate
• D. Barium chloride

Explanation: Zinc acetate acts as an accelerator in zinc oxide cements, shortening the setting time.

• A. 3-4
• B. 4-5
• C. 6-7
• D. 7-8

Explanation: Although freshly mixed zinc phosphate cement is strongly acidic, its acidity decreases as it sets, reaching approximately pH 6 to 7 when…

• A. Zinc phosphate
• B. Polycarboxylate
• C. Glass ionomer
• D. Silicate

Explanation: Silicate cement is the most irritating because its phosphoric-acid liquid produces a very low initial pH and the material can release…

• A. 5
• B. 7
• C. 8
• D. 1.7

Explanation: Polycarboxylate cement liquid contains aqueous polyacrylic acid and is strongly acidic, with a pH around 1.7.

• A. Cement liquid
• B. Glycerin-water solution
• C. Alcohol
• D. Only water

Explanation: For shade selection, the cement powder is mixed with a glycerin-water medium because it approximates the optical effect of the cement…

• A. Increased in the ratio of powder to liquid
• B. Diluting the liquid with water
• C. Decrease the addition of powder to liquid
• D. Increase the addition of powder to liquid

Explanation: Reducing the powder-to-liquid ratio retards zinc phosphate cement by leaving more acid liquid to react and producing a less concentrated…

• A. 1-2μ
• B. 10-20μ
• C. 60-80μ
• D. 20-40μ

Explanation: A luting cement should form a very thin film so that a crown or inlay can seat completely; the usual film thickness is about 25…

• A. Film thickness
• B. Good compressive strength
• C. Lack of irritation
• D. Low solubility

Explanation: The thin film produced by zinc phosphate cement is its important luting advantage because it allows accurate seating of a restoration.

• A. GIC
• B. Copper cement
• C. Zinc oxide eugenol cement
• D. Zinc phosphate cement

Explanation: Zinc oxide eugenol is especially biocompatible because eugenol has a sedative effect on the pulp and the cement is relatively…

• A. None of the above
• B. Phosphoric acid
• C. Zinc
• D. Zinc oxide

Explanation: Zinc phosphate cement powder is composed mainly of zinc oxide, with smaller amounts of magnesium oxide and other modifiers.

• A. Leuting
• B. Temporary restoration
• C. Permanent restoration
• D. Die material

Explanation: Polycarboxylate cement is primarily used as a luting cement for permanently cementing crowns, bridges and orthodontic bands.

• A. Temperature of mixing stab
• B. Liquid powder ratio
• C. Speed of mixing
• D. Addition of few drops of water

Explanation: The powder-liquid ratio has the greatest effect on the strength of ZOE cement: increasing the powder proportion generally produces a…