MDS PREP
What is the recommended thickness of the luting agent film for optimal effectiveness?
1) 50 µm
2) 25 µm
3) 15 µm
4) 5 µm
According to the text, a luting agent must be sufficiently fluid to flow into a continuous film of 25 µm thickness or less without fragmentation.
What is the primary function of a luting agent in the context of dental restorations?
1) To bond the restoration to the tooth
2) To provide a protective barrier against bacteria
3) To insulate the tooth from thermal changes
4) To fill in gaps caused by tooth decay
A luting agent's primary function is to bond the restoration to the tooth and enhance its retention.
Ability of an orthodontic wire to spring back to Its original shape is evaluated by
1) Brittleness
2) Resilience
3) Tensile strength
4) Toughness
Dental Materials Answer: 2
Resilience is the amount of energy absorbed by a structure when it is stressed to proportional Limit.
The elastic area of the stress-strain graph gives resilience; entire area up to breaking point is a measure of toughness.
The slope of straight Line gives Young’s modulus.
Purpose of adding indium to metal alloy in porcelain fused to metal is
1) To improve bonding
2) To increase strength
3) To decrease porosity
4) To match the thermal expansion of metal and procelain
Dental Materials Answer: 1
What is the primary advantage of resin teeth over porcelain teeth in terms of impact resistance and ductility?
1) Resin teeth are more likely to chip or fracture.
2) Resin teeth have better dimensional stability.
3) Resin teeth have greater wear resistance.
4) Resin teeth are less likely to chip or fracture.
Resin teeth are more ductile than porcelain teeth, which means they can absorb and distribute forces better, making them less prone to chipping or fracturing on impact.
What are the three physical properties controlled by the ANSUADA Specification No. 1 (ISO 24234) for dental amalgam?
1) Creep, tensile strength, and thermal expansion.
2) Compressive strength, hardness, and density.
3) Creep, compressive strength, and dimensional change.
4) Tensile strength, modulus of elasticity, and corrosion resistance.
The specification controls the qualities of dental amalgam by listing requirements for creep, compressive strength, and dimensional change.
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.
Apart from composites and ceramics, another material that could be copy milled easily and inexpensively is:
1) Molybdenum
2) Germanium
3) Titanium
4) Chromium
Dental Materials Answer: 3
Fabrication of ceramics and metals like titanium that are difficult to cast, is done by CAD-CAM process and copy milling.