Dental Materials Final (Winter Quarter)

Front 1

steeper and depper energy well results in (more symmetrical results in?)

Back 1

higer mp and bp, more energy to separate (lower coeffecieint of thermal expansion)

Front 2

hue, value, chroma,

Back 2

wavelength, brightness (luminance), degree a color varies from the achromatic color next to it (saturation)

Front 3

define heat of fusion

Back 3

calories of heat required to convert one g materal from solid to liquid at mp. L = heat absorbed/mass

Front 4

define thermal conductivity

Back 4

quantity of heat per second passing through a body one cm think when the temp difference of the sides is 1 degree

Front 5

define specific heat

Back 5

the amount of heat needed to raise 1 g material 1 degree

Front 6

define thermal diffusivity

Back 6

the rate of heat transmission = thermal conductivity/(specific heat*density)

Front 7

linear thermal coefficient of expansion

Back 7

change in length of a metrial from a 1 degree change in temperature

Front 8

stress

Back 8

the internal reaction to the external force, defined as force/area over which force acts

Front 9

strain

Back 9

change in shape due to deformation

Front 10

modulus of elasticity corresponds to what on the stress/strain curve

Back 10

the slope (before yield strength is reached...)

Front 11

5 types of gypsum

Back 11

1: impression plaster; 2 model plaster; 3: dental stone; 4: improved stone, high strength; 5: dental stone hi strength +hi expansion

Front 12

how is type IV or V stone formed

Back 12

gypsum (CaSO4 - 2H20) is heated with steam and CaCl2 to form rhomboid crystalline shape

Front 13

which hyrocolloids are reversibe and irreversible

Back 13

agar: reversible; alginate: irreversible (short word with short word long with long)

Front 14

define colloidal system

Back 14

consists of two phases, a dispersed phase with particles 5-200 nm in diameter and a continuous phase.

Front 15

sol vs gel

Back 15

agars are supplied as gel, heated become sol, on cooling, gel again