NEET MDS Shorts
843352
Dental MaterialWarpage of an impression compound occurs when the surface of the compound is hard and inside is soft
710793
Dental Material
A zinc-containing amalgam that has been contaminated by moisture will result in delayed expansion and reduced compressive strength
800575
Dental Materialthe casting ring is lined with asbestos to prevent confinement of mold expansion
813981
Dental MaterialAn impression compound is a type of material used in dentistry to take
impressions of the oral cavity. It is a reversible hydrocolloid that can be
manipulated and shaped at room temperature and then changes to a gel-like state
when it absorbs moisture and heat from the oral cavity. The setting process of
an impression compound is not accelerated by a warm, humid day; rather, it is
the presence of moisture and the body's temperature that cause it to set.
167242
Dental MaterialElgiloy arch wire is a Cobalt chromium nickel alloy
755122
Dental Materialthe initial release is generally higher, making 0.075 mg during the 1st week
the rate of release is typically highest during the initial few hours and days after placement and then decreases with time
342289
Dental Material
Heating a gypsum cast to a temperature above 90°C will remove water of
crystallization and strengthen it. This process is called "burning out" the
gypsum, and it is used to remove the remaining moisture and improve the cast's
stability and accuracy.
Gypsum casts are made by mixing plaster of Paris (calcium sulfate hemihydrate)
with water. When the material sets, it forms calcium sulfate dihydrate crystals
with water molecules trapped within the crystal lattice, known as water of
crystallization. Heating the cast above 90°C causes the water of crystallization
to be released, which results in the cast becoming stronger and more rigid. This
process does not cause the cast to expand but rather to shrink slightly as the
water is removed. Excess gauging water is typically removed during the initial
setting process.
151238
Dental MaterialOptimum strength of alginate gels is obtained by recommended W/P ratio