MDS PREP
Which of the following denture base materials has the highest linear shrinkage?
1) High-impact acrylic resin
2) Vinyl acrylic resin
3) Conventional acrylic resin
4) Rapid heat-cured acrylic resin
Rapid heat-cured acrylic resin has the highest linear shrinkage at 0.97%, which can affect the fit and stability of the denture.
What is the typical intensity range of a dental argon laser?
1) 1-10 mW.
2) 100-500 mW.
3) 500-1000 mW.
4) More than 1000 mW.
Dental argon lasers typically operate within the range of 100 to 500 mW, providing sufficient power for soft tissue procedures and some hard tissue interactions.
What is the effect of increasing the concentration of the amine initiator in a light-cured composite?
1) It decreases the depth of cure.
2) It increases the depth of cure.
3) It has no effect on the depth of cure.
4) It can lead to premature polymerization.
An excessive amount of amine initiator can lead to a faster reaction rate and a decrease in the depth of cure, as the light may not be able to penetrate deep enough into the material to activate the entire polymerization process.
What are the main properties of Compomers?
1) High elasticity and high load deflection rate.
2) High modulus of elasticity and low shrinkage.
3) Easy to inject, shape, and polish with good aesthetics.
4) High thermal conductivity and good radiopacity.
Compomers are known for their ease of use, being non-sticky, and simple to place and shape. They are a hybrid of glass ionomer and composite resin properties, offering good aesthetics and user-friendly handling.
What is the effect of over- or under-triturating amalgam on its compressive and tensile strength?
1) Over-triturating increases both compressive and tensile strength in all amalgams.
2) Under-triturating increases both compressive and tensile strength in all amalgams.
3) Over-triturating decreases both compressive and tensile strength in all amalgams.
4) Over-triturating increases creep and under-triturating decreases it.
Over-triturating increases creep, and under-triturating lowers it.
What is the ADA specification for the gelation temperature of agar-agar hydrocolloids?
1) It should not be less than 32°C
2) It should be exactly 32°C
3) It should be more than 32°C
4) There is no specific ADA specification for gelation temperature
The American Dental Association (ADA) Specification-11 states that the gelation temperature should not be less than 32°C to ensure proper setting and avoid distortion of the impression.
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 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.