MDS PREP
The point at which a stress of a material exhibits a specific limited deviation P Is called
1) Proportional limit
2) Tensile strength
3) Ultimate strength
4) Yield strength
Dental Materials Answer: 4
Yield strength is the stress required to produce plastic deformation.
What is the effect of over- or under-triturating amalgam on its compressive and tensile strength?
1) Over-triturating increases both compressive and tensile strength in all amalgams.
2) Under-triturating increases both compressive and tensile strength in all amalgams.
3) Over-triturating decreases both compressive and tensile strength in all amalgams.
4) Over-triturating increases creep and under-triturating decreases it.
Over-triturating increases creep, and under-triturating lowers it.
What is the main component of zinc oxide-eugenol cement?
1) Zinc oxide
2) Silica
3) Phosphoric acid
4) Polycarboxylate acid
Zinc oxide-eugenol cement is primarily composed of zinc oxide and eugenol.
What is the role of camphorquinone in photocuring of resin composites?
1) It emits blue light for curing.
2) It absorbs blue light and initiates polymerization.
3) It enhances the color stability of the composite.
4) It is a filler material for increasing strength.
Camphorquinone is a photosensitizer that absorbs blue light and initiates the free radical polymerization of the resin when irradiated, leading to cross-linking and setting of the composite.
What type of cement is most commonly used for cementing metal crowns and bridges?
1) Zinc oxide-eugenol
2) Zinc phosphate
3) Glass ionomer
4) Resin cement
Resin cements are commonly used for cementing metal crowns and bridges due to their high bond strength and durability.
What is the primary function of gold foil in a direct gold restoration?
1) To provide a rigid framework for the powdered gold
2) To enhance the aesthetic appeal of the restoration
3) To improve the adhesion of the gold to the tooth structure
4) To act as a barrier between the gold and the oral environment
Gold foil is used in direct gold restorations to create a three-dimensional structure that can hold the loosely bound powdered gold in place. The foil acts as a container and facilitates the condensation of the gold particles into a cohesive mass, which is then adapted to the prepared cavity.
What is the primary difference between a glass ionomer and a resin-modified glass ionomer cement?
1) Setting time
2) Mechanism of bonding
3) Compressive strength
4) Fluoride release
The primary difference is the presence of resin in resin-modified glass ionomer, enhancing bonding and strength.
What is the function of benzoyl peroxide in the composition of denture base resin powder?
1) It acts as a filler
2) It acts as a cross-linking agent
3) It acts as an initiator
4) It acts as an inhibitor
Benzoyl peroxide in the powder of denture base resin is responsible for initiating the polymerization process when it reacts with the monomer in the liquid component.