MDS PREP
What are the three physical properties controlled by the ANSUADA Specification No. 1 (ISO 24234) for dental amalgam?
1) Creep, tensile strength, and thermal expansion.
2) Compressive strength, hardness, and density.
3) Creep, compressive strength, and dimensional change.
4) Tensile strength, modulus of elasticity, and corrosion resistance.
The specification controls the qualities of dental amalgam by listing requirements for creep, compressive strength, and dimensional change.
What are microfilled composites known for?
1) Their high wear resistance.
2) Their high translucency.
3) Their ease of manipulation.
4) Both A and B.
Microfilled composites contain very fine silica particles (0.04 to 0.2 µm in diameter), which give them excellent translucency and a high surface area for better filling of small restorations.
Which of the following is not a type of oil-based cement?
1) Zinc oxide-eugenol
2) Zinc phosphate
3) Nano-eugenol-zinc oxide
4) All of the above are oil-based cements
Zinc oxide-eugenol is the only oil-based cement mentioned in the text.
What is the maximum allowable level of mercury in the blood?
1) 0.5 µg/L
2) 3 µg/L
3) 5 µg/L
4) 10 µg/L
The maximum allowable level of mercury in the blood is 3 µg/L according to the given text.
What is the typical polymer-to-monomer ratio required for denture base resin?
1) 1:1
2) 2:1
3) 3:1
4) 4:1
The accepted ratio of polymer to monomer for denture base resin is 3:1 volume, allowing sufficient wetting of the polymer particles.
During crown cementation, complete filling of crown with cement is not advisable due to :
1) Increased risk of bubble entrapment
2) Increased seating time
3) Increased pressure required for seating crown
4) All of the above
Dental Materials Answer: 4
It is not advisable to fill the crown completely with cement due to following 4 reasons:
1. the time for removal of excess cement elevates.
2. the risk for bubble entrapment increases
3. increased pressure may be needed
4. the time for seating increases
What happens if the water temperature exceeds 50°C during the mixing of gypsum products?
1) The setting reaction is accelerated.
2) The setting reaction is retarded.
3) No reaction occurs.
4) The material becomes less soluble.
If the temperature of the water used to mix gypsum products exceeds 50°C, it can slow down the setting reaction due to the reversible nature of the gypsum crystal formation at higher temperatures.
What is the typical particle size of silica in microfilled composites?
1) 0.5-1 µm.
2) 0.04-0.2 µm.
3) 1-10 µm.
4) 10-30 µm.
Microfilled composites have a very high surface area with silica particles diameters of 0.04 to 0.2 µm, which provides excellent aesthetic results and polishability.