MDS PREP
What is the main advantage of using Ormocers in dental restorations?
1) They have a high coefficient of thermal expansion.
2) They have excellent biocompatibility and resistance to masticatory loading.
3) They are easy to manipulate and require minimal finishing.
4) They can be used in high-stress bearing areas without reinforcement.
The main advantage of using Ormocers is their excellent biocompatibility and resistance to masticatory loading. They also have good esthetic properties, resembling those of natural teeth.
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 type of dental cement is used in cases of rampant caries and unhygienic oral conditions?
1) Zinc polyacrylate
2) Calcium sulfate
3) Zinc oxide-eugenol
4) Calcium hydroxide
Calcium hydroxide is used in cases of rampant caries and unhygienic oral conditions due to its antibacterial and tissue-dissolving properties.
What is the pH of zinc polycarboxylate cement after 28 days?
1) 2.8
2) 3.7
3) 5.2
4) 5.8
The pH values provided in the text indicate that zinc polycarboxylate cement reaches a pH of 5.8 after 28 days.
What is the purpose of using a voltage regulator with an amalgamator?
1) To maintain consistent speed regardless of line voltage.
2) To reduce the speed of the amalgamator.
3) To increase the speed of the amalgamator.
4) To monitor the temperature during mixing.
A voltage regulator helps maintain consistent speed and proper mixing of amalgam regardless of fluctuations in line voltage.
What happens to acrylic resin when it absorbs water?
1) It expands linearly
2) It contracts linearly
3) It remains the same dimensionally
4) It swells in volume
When acrylic resin absorbs water, it expands linearly by approximately 0.23%, which can affect the fit and function of the denture.
VLC resins are also called
1) microwave-activated resins.
2) tertiary amine-activated resins.
3) light-activated resins.
4) heat-activated resins.
Dental Materials Answer: 3
The first light-activated systems were formulated for UV light to initiate free radicals. Today the UV light-cured composites have been replaced by visible blue-light-activated systems with greatly improved depth of cure, a controllable working time, and other advantages.
Because of these advantages, visibly light-activated composites are more widely used than are chemically acti wited materials.
The sprue former should be attached to the wax pattern
1) At the thinnest point
2) At the point of greatest bulk
3) At the junction of proximal and
4) None of the above occulsal surfaces
Dental Materials Answer: 2
The sprue former should be attached to the wax pattern at the area of more bulk