MDS PREP
The constituent used in porcelain that fuses at high temperature to form matrix
1) Soda ash
2) Feldspar
3) Quartz
4) Koalin
Dental Materials Answer: 3
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 gelation temperature range of a reversible hydrocolloid?
1) 37°C - 50°C
2) 50°C - 70°C
3) 70°C - 100°C
4) 100°C - 120°C
The gelation temperature is the point at which the material transforms from a sol to a gel, which is critical for impression making.
What is the primary reason for using zinc polycarboxylate cement as a luting agent?
1) Its high compressive strength
2) Its ability to bond chemically to tooth structure
3) Its ease of manipulation
4) Its insolubility in oral fluids
Zinc polycarboxylate cement is favored as a luting agent for its chemical bonding capability with tooth structure.
What are the characteristics of a condenser that allows it to be considered user-friendly?
1) High elastic limit and steep force-deflection curve.
2) Low elastic limit and high springiness.
3) Flat slope and high elastic range.
4) High elastic limit and high springiness.
A condenser that is considered user-friendly typically has a high elastic limit and high springiness, allowing for better control and easier placement of the restorative material.
What is the effect of trituration time on the dimensional change of spherical amalgam alloys?
1) It increases with increased trituration time.
2) It decreases with increased trituration time.
3) It is not affected by trituration time.
4) It is greatest at normal trituration time.
Compressive and tensile strengths of spherical alloys are greatest at normal trituration time.
What is the typical film thickness required for zinc polycarboxylate cement?
1) 50 µm
2) 25 µm
3) 15 µm
4) 5 µm
As a luting material, zinc polycarboxylate should form a film of less than 25 µm.
How does water sorption affect the overall vertical dimension of a denture?
1) It increases the vertical dimension
2) It decreases the vertical dimension
3) It has no effect on the vertical dimension
4) It depends on the type of resin used
The effect of water sorption on vertical dimension varies with the type of resin.