MDS PREP
Which of the following is NOT a component of dental amalgam?
1) Finely ground silver/tin metal powder
2) Mercury
3) Hydrophilic polymer
4) Zirconia
Dental amalgam is a mixture of metallic elements consisting of silver, tin, copper, and sometimes zinc, combined with liquid mercury to form an amalgamated alloy. The mercury acts as a matrix that bonds the metal particles together. It does not contain hydrophilic polymers, which are typically found in resin-based composite materials used for tooth-colored restorations.
What is the main advantage of using Ormocers in dental restorations?
1) They have a high coefficient of thermal expansion.
2) They have excellent biocompatibility and resistance to masticatory loading.
3) They are easy to manipulate and require minimal finishing.
4) They can be used in high-stress bearing areas without reinforcement.
The main advantage of using Ormocers is their excellent biocompatibility and resistance to masticatory loading. They also have good esthetic properties, resembling those of natural teeth.
Which of the following is NOT a type of zinc phosphate cement?
1) Type I
2) Type II
3) Type III
4) Type IV
Type IV is not a recognized classification for zinc phosphate cements.
What is the ideal consistency of a luting agent according to ANSI/ADA Specification No. 96 (ISO 9917)?
1) Thixotropic
2) Plastic
3) Thin film
4) Putty
The ideal luting agent consistency is not explicitly mentioned in the text, but it should be able to flow into a film less than 25 µm thick without fragmentation.
What is the primary function of the eugenol in zinc oxide-eugenol cement?
1) To provide antimicrobial properties
2) To act as a plasticizer
3) To initiate the setting reaction
4) To increase the compressive strength
The eugenol in zinc oxide-eugenol cement acts as a plasticizer, providing temporary softness for easier manipulation.
What are the requirements for a good temporary cementing agent?
1) High compressive strength and good thermal conductivity
2) Low compressive strength and good thermal conductivity
3) High compressive strength and low thermal conductivity
4) Low compressive strength and low thermal conductivity
The ideal requirements for temporary cements include promoting the healing process and having a low compressive strength to facilitate removal.
What is the typical mixing time for temporary cementing materials?
1) 1-5 minutes
2) 5-15 minutes
3) 15-30 minutes
4) 1-15 minutes
The text does not specify the exact mixing time for temporary cements, but it states that the mixing time for all three varieties is approximately 1-15 minutes.
What is the primary advantage of resin teeth over porcelain teeth in terms of impact resistance and ductility?
1) Resin teeth are more likely to chip or fracture.
2) Resin teeth have better dimensional stability.
3) Resin teeth have greater wear resistance.
4) Resin teeth are less likely to chip or fracture.
Resin teeth are more ductile than porcelain teeth, which means they can absorb and distribute forces better, making them less prone to chipping or fracturing on impact.