MDS PREP
What is the typical wavelength absorbed by camphorquinone during photopolymerization?
1) 300-400 nm
2) 400-500 nm
3) 500-600 nm
4) 600-700 nm
Camphorquinone primarily absorbs blue light, which falls within the 400-500 nm wavelength range, triggering the polymerization process.
What is the typical average particle size of powered gold used in dental restorations?
1) 15 ?ms
2) 10 ?ms
3) 5 ?ms
4) 20 ?ms
The average particle size of powered gold used in dental restorations is 15 ?ms. This size allows for the gold to be manipulated and condensed properly within the cavity preparation to achieve the desired restorative outcome.
What is the primary advantage of using resin cements over other types of cements?
1) Higher compressive strength
2) Improved adhesion to the tooth structure
3) Lower film thickness requirement
4) Faster setting time
Resin cements are known for their excellent adhesion, providing a strong bond to tooth structure and restorative materials.
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 is the typical pH of zinc polycarboxylate cement immediately after mixing?
1) Less than 2
2) Between 2 and 4
3) Between 4 and 7
4) Greater than 7
The pH is mentioned to be around 2.8 after 3 minutes, which indicates an acidic nature initially.
What is the significance of the line of force during the condensation of dental amalgam?
1) The line of force determines the speed at which the amalgam is condensed.
2) The line of force is the amount of force applied to the condenser during condensation.
3) The line of force describes the direction of force applied with a condenser.
4) The line of force is the amount of force needed to cause the amalgam to flow into the preparation.
The line of force refers to the direction in which the force is applied during condensation. It is crucial to apply the force in a controlled and precise manner to avoid causing damage to the tooth or the restoration. The text mentions that the force applied with a condenser parallels the long axis of the instrument shaft, with specific angles recommended for different areas of the cavity.
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 range for dimensional change between 5 minutes and 124 hours for an amalgam specimen according to ANSI/ADA Specification No. 1 (ISO 24234)?
1) -5 to +10 ?m/cm
2) -10 to +15 ?m/cm
3) -15 to +20 ?m/cm
4) -20 to +25 ?m/cm
The specification requires that the dimensional change for a cylindrical specimen must fall within the range of -15 to +20 ?m/cm for 5 minutes to 124 hours after setting.