MDS PREP
What is the main advantage of using glass ionomer cements in dentistry?
1) High compressive strength
2) Chemical bonding to tooth structure
3) Low cost
4) High aesthetic appeal
Glass ionomer cements are known for their ability to chemically bond to tooth structure, particularly dentin and enamel.
What is the primary function of a dental sealer in restorative procedures?
1) To prevent microleakage
2) To desensitize the tooth
3) To enhance the aesthetics of the restoration
4) To reinforce the tooth structure
A dental sealer is used to fill the microscopic spaces between the restorative material and the tooth structure, primarily to prevent microleakage.
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 minimum compressive strength required for lining materials?
1) 1.0 MPa
2) 3.0 MPa
3) 5.0 MPa
4) 10 MPa
Lining materials must have a minimum compressive strength of 5 MPa to withstand the forces in the oral cavity.
What is the primary difference between Class I and Class II gypsum products?
1) Setting time.
2) Compressive strength.
3) Expansion.
4) Both A and B.
Class II (dental stone) has a higher compressive strength compared to Class I (dental plaster), making it suitable for model making and other applications requiring higher durability.
What is the maximum allowable level of mercury in the blood according to the given information?
1) 1 �g/L
2) 3 �g/L
3) 5 �g/L
4) 10 �g/L
The maximum allowable level of mercury in the blood is specifically mentioned as 3 �g/L in the provided text.
What is the primary disadvantage of using zinc oxide-eugenol as a permanent cement?
1) Low compressive strength
2) Shrinkage during setting
3) Difficulty in achieving a precise fit
4) Potential toxicity
While great for temporary cementation, its primary disadvantage for permanent use is its potential to cause tooth discoloration and pulpal irritation.
What is the liquefaction temperature of agar hydrocolloid?
1) 37�C - 50�C
2) 60�C - 70�C
3) 70�C - 100�C
4) 50�C - 65�C
Agar hydrocolloid must be heated to a liquefaction temperature between 70�C and 100�C to be suitable for impression taking.