MDS PREP
What is the typical polymer-to-monomer ratio required for denture base resin?
1) 1:1
2) 2:1
3) 3:1
4) 4:1
The accepted ratio of polymer to monomer for denture base resin is 3:1 volume, allowing sufficient wetting of the polymer particles.
What is the primary component of zinc polycarboxylate cement?
1) Zinc oxide
2) Polyacrylic acid
3) Titanium dioxide
4) Calcium hydroxide
Zinc polycarboxylate cement primarily consists of zinc oxide and polyacrylic acid.
What is the maximum allowable level of mercury in the blood?
1) 0.5 µg/L
2) 3 µg/L
3) 5 µg/L
4) 10 µg/L
The maximum allowable level of mercury in the blood is 3 µg/L according to the given text.
What is the maximum rate of acid erosion allowed for zinc polyacrylate cements according to ADA Specification No. 96?
1) 2.0 mm/hour
2) 4.0 mm/hour
3) 6.0 mm/hour
4) 8.0 mm/hour
The ADA specification sets a limit of 2.0 mm/hour for acid erosion to ensure the cement’s stability in the oral environment.
Apart from composites and ceramics, another material that could be copy milled easily and inexpensively is:
1) Molybdenum
2) Germanium
3) Titanium
4) Chromium
Dental Materials Answer: 3
Fabrication of ceramics and metals like titanium that are difficult to cast, is done by CAD-CAM process and copy milling.
What are the common types of water-based dental cements?
1) Zinc polycarboxylate
2) Calcium sulfate
3) Zinc oxide-eugenol
4) All of the above
Water-based cements include zinc polycarboxylate and calcium sulfate.
How do resin teeth typically bond with denture base resins?
1) Through mechanical undercuts.
2) Through silanization.
3) By forming chemical bonds.
4) Both A and B.
Resin teeth are capable of forming chemical bonds with commonly used denture base resins, which allows for a stronger and more durable bond compared to porcelain teeth.
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.