MDS PREP
How many grams of high-density noble metal alloy is required for casting of a molar?
1) 3 gms
2) 6 gms
3) 9 gms
4) 12 gms
Dental Materials Answer: 3
With high-density noble metal alloy 6 grams is adequate for premolar and anterior castings, 9 grams is adequate for molar casting and 12 grams is adequate for pontics.
How does the elastic range of a wire affect its ability to be activated in orthodontic appliances?
1) A high elastic range allows for greater activation without causing permanent deformation.
2) A low elastic range allows for more precise and controlled activation.
3) The elastic range does not affect wire activation; it is only dependent on the force applied.
4) A wire with a high elastic range is more prone to permanent deformation during activation.
The elastic range of a wire determines the extent to which it can be deflected and still return to its original shape without permanent deformation. A wire with a high elastic range can be activated to a greater extent before it reaches its plastic range, making it suitable for larger tooth movements.
Austenite is an alloy of iron and carbon with the iron in
1) Alpha form
2) Beta form
3) Gamma form
4) None of the above
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 Today the UV light-cured composites have been replaced by visible blue-light-activated systems with greatly improved depth of cure, a controllable working time, and other advantages.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.
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 are the stoichiometric formulas for the gamma (?), epsilon (?), and zeta (?) phases in dental amalgams?
1) ?: Ag3Sn, ?: Cu3Sn8, ?: Cu3Sn
2) ?: Ag3Sn, ?: AgSn, ?: CuSn
3) ?: AgSn, ?: Cu3Sn, ?: Ag3Sn8
4) ?: AgSn, ?: CuSn, ?: Ag3Sn.
?: Ag3Sn, ?: Cu3Sn8, ?: Cu3Sn
What is the effect of trituration time on the dimensional change of spherical amalgam alloys?
1) It increases with increased trituration time.
2) It decreases with increased trituration time.
3) It is not affected by trituration time.
4) It is greatest at normal trituration time.
Compressive and tensile strengths of spherical alloys are greatest at normal trituration time.
What are the main components of a typical dental composite resin?
1) Monomers, fillers, initiators, and accelerators.
2) Resins, fillers, catalysts, and diluents.
3) Polymers, pigments, and plasticizers.
4) Monomers, fillers, and cross-linking agents.
Dental composite resins typically consist of a resin matrix (monomers), filler particles (such as silica or glass), initiators (like camphorquinone), and accelerators (such as amines) to control the setting process.
What is the ideal thickness of a luting agent film for it to be effective?
1) 50 µm
2) 25 µm
3) 10 µm
4) 5 µm
An effective luting agent must be able to flow into a continuous film of 25 µm thickness or less without fragmentation.