MDS PREP
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 maximum allowable level of mercury in the blood according to the given information?
1) 1 µg/L
2) 3 µg/L
3) 5 µg/L
4) 10 µg/L
The maximum allowable level of mercury in the blood is specifically mentioned as 3 µg/L in the provided text.
What is the pH of zinc polycarboxylate cement after 28 days?
1) 2.8
2) 3.7
3) 5.2
4) 5.8
The pH values provided in the text indicate that zinc polycarboxylate cement reaches a pH of 5.8 after 28 days.
Which of the following is not a type of oil-based cement?
1) Zinc oxide-eugenol
2) Zinc phosphate
3) Nano-eugenol-zinc oxide
4) All of the above are oil-based cements
Zinc oxide-eugenol is the only oil-based cement mentioned in the text.
What is the typical composition of the mica crystals in a fluoromica glass ceramic like Dicor?
1) SiO2 · K2O · MgO · Al2O3 · ZrO2
2) Al2O3 · K2O · Na2O · MgO · ZrO2
3) SiO2 · CaO · Al2O3 · ZrO2
4) Al2O3 · Na2O · MgO · CaO
Fluoromica glass ceramics like Dicor have a composition based on mica crystals consisting of silica, potassium oxide (K2O), magnesium oxide (MgO), and aluminum oxide (Al2O3), with zirconium oxide (ZrO2) added for stability. Fluorides are included in the mixture to achieve fluorescence in the finished prosthesis. The material is castable and shares some similarities with traditional dental ceramics but with unique properties derived from its crystalline structure.
What are the advantages of using light-cured composites over chemically cured products?
1) Less porosity, less staining, increased strength, enhanced color stability, and control of working time.
2) Faster curing time, better translucency, and less shrinkage.
3) Longer shelf life and lower cost.
4) Higher wear resistance and easier to manipulate.
Light-cured composites do not require mixing, which reduces porosity and staining. They also allow for better control over working time and increased color stability due to the use of aliphatic amines.
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.
Which type of amalgam alloy has the lowest compressive strength at 1 hour?
1) High-copper lathe-cut alloy
2) Low-copper lathe-cut alloy
3) High-copper spherical alloy
4) Low-copper spherical alloy
The compressive strength at 1 hour is lowest for the low-copper lathe-cut alloy, which is 45 MPa.