MDS PREP
The opacity in ceramics is achieved by adding
1) Boric oxide
2) Copper oxide
3) Silica
4) Titanium oxide
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 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 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.
If a partially set material is seated, the die material obtained from such impression will be
1) Oversized
2) Undersized
3) Retains its dimension due to elasticity of the material
4) Dimensions will be un changed but may leave a rough surface
Dental Materials Answer: 2
If Impression tray comprising of elastomeric impression material is seated too late as elasticity starts to develop, raised seating pressure is applied to overcome the stiffness of impression material.
Because of recovery of excessive elastic deformation there is development of distortion
The die produced in the inaccurate impression is too narrow and too short.
What is the typical setting time range for Type II (Normal set) alginate impression material?
1) 1-2 minutes
2) 2-4 minutes
3) 4-6 minutes
4) 6-8 minutes
Type II (Normal set) alginate impression material has a setting time of 2-4 minutes, which is longer than the fast-setting Type I material.
What does the term "A form" of Gutta Percha refer to?
1) At room temperature
2) After condensation
3) After heating to 56°C - 62°C
4) After mixing with Zinc Oxide
When heated to 56°C - 62°C, Gutta Percha gets converted to the A form, which is crucial for its expansion during the sealing process.
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.