MDS PREP
What is the typical setting time for zinc oxide-eugenol temporary cement?
1) Less than 5 minutes
2) 5-10 minutes
3) 10-15 minutes
4) More than 15 minutes
Zinc oxide-eugenol temporary cement typically sets in about 5-10 minutes.
What is the typical setting time range for Type II (Normal set) alginate impression material?
1) 1-2 minutes
2) 2-4 minutes
3) 4-6 minutes
4) 6-8 minutes
Type II (Normal set) alginate impression material has a setting time of 2-4 minutes, which is longer than the fast-setting Type I material.
How does the degree of polymerization affect the strength of resin?
1) There is no correlation between the two
2) Higher degree of polymerization results in increased strength
3) Lower degree of polymerization results in increased strength
4) The strength is unaffected by the degree of polymerization
A higher degree of polymerization in resins generally correlates with greater strength, as more polymer chains are formed and cross-linked.
What is the typical range of water to powder ratio for dental stone?
1) 0.28-0.30.
2) 0.40-0.45.
3) 0.45-0.50.
4) 0.50-0.60.
Dental stone typically has a lower water to powder ratio compared to other gypsum products, which gives it higher strength and durability suitable for making dental models.
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.
Bonding of GIC to tooth structure is brought about by
1) metal ions
2) hydroxyl bond
3) carboxyl bond
4) ionic bond
Dental Materials Answer: 3
one ot the main adanhtges of GIC as a restoratie material was its ability to form chemical bonds with the tooth structure.
Bonding in GIC primarily invokes chelation of carboxyl groups of the polyacids sith the calcium in the apatite of enamel and dentin. Bond rength of enamel is always greater than that of dentin due to higher mineral content. The bonding is improved by the removal of the debris layer called smear layer’ by a process called conditioning.
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 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.