MDS PREP
Gypsum Bonded Investment should NOT be heated above
1) 700°C
2) 750°C
3) 800°C
4) 900°C
Dental Materials Answer: 1
What are the two types of alginate impression materials according to ADA specification No. 18?
1) Type I - Fast set with a setting time of 1-2 minutes, Type II - Normal set with a setting time of 2-4 minutes
2) Type I - Slow set with a setting time of 3-5 minutes, Type II - Medium set with a setting time of 4-6 minutes
3) Type I - Fast set with a setting time of 1-2 minutes, Type II - Slow set with a setting time of 3-5 minutes
4) Type I - Normal set with a setting time of 1-2 minutes, Type II - Fast set with a setting time of 2-4 minutes
ADA specification No. 18 categorizes alginate impression materials into two types: Type I (Fast set) with a setting time of 1-2 minutes and Type II (Normal set) with a setting time of 2-4 minutes.
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 Today the UV light-cured composites have been replaced by visible blue-light-activated systems with greatly improved depth of cure, a controllable working time, and other advantages.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
What is the ADA specification for the gelation temperature of agar-agar hydrocolloids?
1) It should not be less than 32°C
2) It should be exactly 32°C
3) It should be more than 32°C
4) There is no specific ADA specification for gelation temperature
The American Dental Association (ADA) Specification-11 states that the gelation temperature should not be less than 32°C to ensure proper setting and avoid distortion of the impression.
What is the main disadvantage of using zinc phosphate cement?
1) Low compressive strength
2) Potential for pulpal irritation
3) Difficulty in removal
4) High cost
While it has good mechanical properties, poorly placed zinc phosphate cement can cause pulpal irritation.
How does the concentration of mercury in urine relate to neurological changes?
1) Neurological changes are detected at urine mercury levels of 1 µg/L.
2) Neurological changes are detected at urine mercury levels of 10 µg/L.
3) Neurological changes are detected at urine mercury levels of 500 µg/L.
4) There is no established link between mercury concentration in urine and neurological changes.
Neurological changes are not detected until urine mercury levels exceed 500 µg/L, which is significantly higher than the levels associated with amalgam placement.
What is the typical wavelength absorbed by camphorquinone during photopolymerization?
1) 300-400 nm
2) 400-500 nm
3) 500-600 nm
4) 600-700 nm
Camphorquinone primarily absorbs blue light, which falls within the 400-500 nm wavelength range, triggering the polymerization process.