MDS PREP
What are the typical operating speeds for low-, medium-, and high-speed amalgamators?
1) 3000 to 3200 cpm for low-speed, 3500 to 3700 cpm for medium-speed, and 4000 to 4400 cpm for high-speed.
2) 3200 to 3400 cpm for low-speed, 3700 to 3800 cpm for medium-speed, and 4000 to 4400 cpm for high-speed.
3) 3000 to 3200 cpm for medium-speed, 3500 to 3700 cpm for high-speed, and 4000 to 4400 cpm for low-speed.
4) 3200 cpm for low-speed, 3700 cpm for medium-speed, and 4400 cpm for high-speed.
Low-speed amalgamators operate at 3200 to 3400 cpm, medium-speed at 3700 to 3800 cpm, and high-speed at 4000 to 4400 cpm.
What is the minimum 24-hour compressive strength required for dental cement according to ANSI/ADA Specification No. 96 (ISO 9917)?
1) 50 MPa
2) 70 MPa
3) 100 MPa
4) 150 MPa
The text states that the standard luting consistency of dental cement must exhibit a minimum 24-hour compressive strength of 70 MPa.
What is the typical concentration of sodium chloride used as an accelerator in dental plaster?
1) 5%.
2) 10%.
3) 15%.
4) 20%.
A concentration of sodium chloride of about 5% is commonly added to dental plaster to accelerate the setting reaction and reduce the setting time.
What are the primary advantages of Ormocers over conventional composites?
1) Outstanding biocompatibility and minimal shrinkage.
2) High elasticity and superior resistance to masticatory forces.
3) Enhanced wear resistance and fluoride release.
4) All of the above.
Ormocers offer several advantages over conventional composites. They have excellent biocompatibility, minimal shrinkage, and their chemical structure allows for high resistance to masticatory forces. Additionally, they are aesthetically pleasing and can be polished to resemble natural teeth.
What is the typical mixing ratio for zinc polycarboxylate cement?
1) 1:1
2) 1:2
3) 2:1
4) 3:1
The typical mixing ratio for zinc polycarboxylate cement is 1:2 (powder to liquid).
What is the significance of the direction of the applied force during condensation?
1) It is not important for the success of the restoration.
2) It affects the marginal integrity of the restoration.
3) It influences the adaptation of the material to the cavity walls.
4) It does not affect the physical properties of the restoration.
The significance of the direction of the applied force during condensation is that it affects the marginal integrity and adaptation of the material to the cavity walls. It is important to direct the force at an appropriate angle to ensure proper condensation and seating of the material.
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.
How does the presence of the ?2 phase affect the corrosion resistance of high-copper amalgams?
1) It significantly increases the corrosion resistance.
2) It has no effect on the corrosion resistance.
3) It significantly decreases the corrosion resistance.
4) It is the most corrodible phase in high-copper amalgams.
The ?2 phase is the least corrosion-resistant phase in high-copper amalgams.