MDS PREP
What is the typical pH of a resin cement immediately after mixing?
1) Less than 2
2) Between 2 and 4
3) Between 4 and 7
4) Greater than 7
The pH of resin cements is usually slightly acidic after mixing, subject to variation in formulation.
What is the primary purpose of using a thermal insulating base?
1) To protect the pulp from thermal changes
2) To increase the strength of the restoration
3) To improve the aesthetics of the restoration
4) To facilitate the removal of the restoration
The purpose of a thermal insulating base is to protect the pulp from temperature changes during the placement of a restoration.
What is the typical force applied with a condenser during restorative procedures?
1) 0.04-0.4 µm
2) 1-5 µm
3) 3.75 pounds
4) 8.43 pounds
The typical force applied with a condenser during restorative procedures is 3.75 pounds for a 0.5 mm diameter nib, 8.43 pounds for a 0.75 mm diameter, and 15 pounds for a 1 mm diameter nib. The force is applied parallel to the long axis of the instrument shaft.
What is the typical compressive strength of hardened ZnOE impression paste?
1) 0.4-0.7 MPa
2) 7 MPa
3) 245 MPa
4) 32 MPa
The compressive strength of hardened zinc oxide eugenol (ZnOE) impression paste is generally about 7 MPa, indicating its ability to withstand compressive forces without deformation or failure.
Which of the following shows highest permanent deformation following strain in compression :
1) Polysulphide impression material
2) Polyether impression material
3) Condensation silicones
4) Addition silicones
Dental Materials Answer: 1
For permanent deformation following strain in compression, ranking is mentioned below:
Polysulfide > polyethers > condensation silicone > addition silicone
What is the effect of silicate cement on the pulp?
1) It is non-irritating.
2) It is mildly irritating.
3) It is highly irritating.
4) It has no effect.
Silicate cement is classified as a severely irritant to the pulp.
What type of dental cement is used in cases of rampant caries and unhygienic oral conditions?
1) Zinc polyacrylate
2) Calcium sulfate
3) Zinc oxide-eugenol
4) Calcium hydroxide
Calcium hydroxide is used in cases of rampant caries and unhygienic oral conditions due to its antibacterial and tissue-dissolving properties.
What is the elastic limit of a wire, and what happens when a wire is deflected beyond this point?
1) The elastic limit is the point at which the wire begins to deform plastically.
2) The elastic limit is the force needed to permanently deform a wire.
3) The elastic limit is the maximum force a wire can withstand before fracture.
4) The elastic limit is the point at which a wire will always return to its original shape regardless of the force applied.
The elastic limit, also known as the yield strength, is the point at which a wire starts to undergo permanent deformation. When a wire is deflected beyond this point, it does not return to its original shape completely.