MDS PREP
What does ORMOCER stand for in the context of dental filling materials?
1) Organically Modified Resin-ceramic Opportunistic
2) Organically Modified Resin-ceramic Material
3) Organically Modified Ceramic
4) Optimized Resin-ceramic Matrix
ORMOCER stands for Organically Modified Ceramic. These materials are advanced filling options in dentistry with a unique matrix technology and filler particles that result in high biocompatibility and aesthetics.
What is the typical concentration range of phosphoric acid used for enamel etching?
1) 10-20%
2) 20-30%
3) 30-40%
4) 35-50%
Phosphoric acid concentrations between 20% and 30% are commonly used for acid etching of enamel to create a roughened surface for mechanical bonding of restorative materials.
The essential ingredient of dental inlay investment are :
1) Quartz, cristobalite
2) β hemihydrate
3) α hemihydrate
4) Ammonium phosphate
Dental Materials Answer: 3
The essential ingredients of the dental inlay investment employed with the conventional gold casting alloys are a-hemihydrate of gypsum, quartz, or cristobalite, which are allotropic forms of silica.
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 modified form of zinc oxide-eugenol used for temporary cementation?
1) Type I
2) Type II
3) Type III
4) Type IV
The modified form of zinc oxide-eugenol used for temporary cementation is commonly known as Type II due to its lower compressive strength and ease of removal.
What is the role of the silane-coupling agent in the bonding between the filler and matrix in a dental composite material?
1) It acts as a binder to physically hold the filler and matrix together
2) It creates a chemical bond between the filler and the matrix
3) It enhances the mechanical strength of the composite
4) It provides a smooth surface for the filler to be evenly distributed in the matrix
Silane-coupling agents are used to improve the bonding between filler particles and the matrix in dental composite materials. They contain a methacrylic group that can co-polymerize with the dimethacrylate monomers present in the matrix, while also having functional groups that can interact with the filler material, typically silica or glass particles. This dual interaction creates a chemical bond, which enhances the overall stability and strength of the composite material.
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 elastic limit of a wire?
1) The point at which the wire returns to its original shape.
2) The point at which the wire starts to weaken.
3) The point at which the wire yields permanently.
4) The point at which the wire breaks.
The elastic limit of a wire is the point at which it yields permanently, meaning any greater force applied will result in irreversible deformation.