MDS PREP
What is the typical concentration of sodium chloride used as an accelerator in dental plaster?
1) 5%.
2) 10%.
3) 15%.
4) 20%.
A concentration of sodium chloride of about 5% is commonly added to dental plaster to accelerate the setting reaction and reduce the setting time.
What is the typical bond strength of etched enamel with restorative materials?
1) 5-10 MPa.
2) 15-25 MPa.
3) 5-10 MPa.
4) 30-50 MPa.
Properly etched enamel surfaces can achieve bond strengths of approximately 15 to 25 MPa when using suitable restorative materials.
What are Compomers more correctly termed?
1) Methacryloxy decyl pyridinium bromide-modified composite resins
2) Polyacid-modified composite resins
3) Polymethacrylate-based composite resins
4) Glass ionomer-modified composite resins
Compomers are more correctly termed Polyacrylic acid Modified Composite Resins (PMCRs). They are a blend of glass ionomer and composite resin properties, making them user-friendly and suitable for certain restorative procedures.
The opacity in ceramics is achieved by adding
1) Boric oxide
2) Copper oxide
3) Silica
4) Titanium oxide
What is the effect of temperature on the setting time of gypsum products?
1) Increased temperature accelerates the setting reaction.
2) Increased temperature has no effect on the setting reaction.
3) Increased temperature retards the setting reaction.
4) Temperature has an inconsistent effect on the setting reaction.
Higher temperatures generally speed up the chemical reactions involved in the setting of gypsum products, leading to a shorter setting time.
What is the effect of increasing the concentration of the amine initiator in a light-cured composite?
1) It decreases the depth of cure.
2) It increases the depth of cure.
3) It has no effect on the depth of cure.
4) It can lead to premature polymerization.
An excessive amount of amine initiator can lead to a faster reaction rate and a decrease in the depth of cure, as the light may not be able to penetrate deep enough into the material to activate the entire polymerization process.
What is the role of MDPB in dental composites?
1) It provides improved mechanical properties.
2) It acts as an initiator for the polymerization reaction.
3) It enhances the antibacterial activity of the composite material.
4) It reduces the viscosity of the resin.
MDPB (methacryloxy decyl pyridinium bromide) is a quaternary ammonium salt that has been shown to be effective against various streptococci in dental composites. Its inclusion enhances the antibacterial properties of the material.
Which of the following is NOT a type of zinc phosphate cement?
1) Type I
2) Type II
3) Type III
4) Type IV
Type IV is not a recognized classification for zinc phosphate cements.