Quiz 3-physical Properties

Question 1

incident light

Answer 1

reflected, absorbed, or transmitted

Question 2

opacity of dentin and enamel

Answer 2

dentin is more opaque

Question 3

translucency

Answer 3

diffused transmission of light; light is dispersed (not transmitted)

Question 4

opaque

Answer 4

no passage; scattering within may happen

Question 5

refraction

Answer 5

light changes direction in a second medium

Question 6

seeing color

Answer 6

1. source emits light onto
2. object
3. color that we see is reflected off to the observer

Question 7

3 indices of color

Answer 7

Hue, Value, and chroma

Question 8

Hue

Answer 8

The dominant color of the object (red,yellow, or blue)

Question 9

Hue of teeth

Answer 9

yellow to yellow-red

Question 10

value

Answer 10

the lightness or darkness of a color (0 is black and 10 is white) teeth=6-8

Question 11

Value of natural teeth

Answer 11

6-8

Question 12

Chroma

Answer 12

the intensity of a color; is the object rich in color or pale?
0=achromatic and 18=saturated
teeth are weak

Question 13

Color Content

Answer 13

different light sources have different wavelength components

Question 14

better a light source matches standard

Answer 14

higher ranking

Question 15

color rendition index

Answer 15

a measure of how well a light source renders color compared to standard (N daylight)

Question 16

light source for color matching

Answer 16

> 90 CRI

Question 17

Intensity

Answer 17

low level light and high level cause loss of color

Question 18

ideal intensity is

Answer 18

1500-2500 lux

Question 19

surroundings

Answer 19

modify the type of light reaching the object

Question 20

Gloss

Answer 20

object; how much light is reflected off the object (moisture, roughness)

Question 21

Individual response

Answer 21

normal people see different colors

Question 22

color vision

Answer 22

5% of men and .5% of women have color deficiencies

Question 23

receptor fatigue

Answer 23

causes a complementary color to be seen (red square, see blue square left behind)

Question 24

munsell system

Answer 24

plots 3 values of color on a scale; compare to color tabs

Question 25

Spectrophotometer

Answer 25

measures wavelength intensity reflected or transmitted

Question 26

Colorimeter-CIE

Answer 26

Commission international de l'eclarage; international org concerned with light and color

Question 27

L in L*a*B

Answer 27

L= luminance from 0-100

Question 28

A and b in L*a*B

Answer 28

Red=+a and green -a | +b=yellow and -b = blue

Question 29

Can give C lab coordinates

Answer 29

colorimeters and specs

Question 30

Dental shade guide tabs

Answer 30

organized sequence of models

Question 31

metamerism

Answer 31

when two objects appear to match under one light but not under another-metamers

Question 32

Fluorescence

Answer 32

the object emits light when illuminated by a specific light source; in real teeth so necessary in restorations

Question 33

Thermoconductivity

Answer 33

Quantity of heat in C/S passing through a body of 1cm thick with a cross-section of 1cm squared when temp diff is 1 C (conductors have high values)

Question 34

Thermal diffusivity

Answer 34

rate at which body with a nonuniform temp approaches equilibrium

Question 35

liner

Answer 35

layer of cement lining a filling/crown to prevent direct heat transfer to patient

Question 36

coefficient of thermal expansion (CTE)

Answer 36

change in length over original length x the change in temp

Question 37

dental importance of CTE

Answer 37

change in temp causing a change in shape of restoration

Question 38

electrical conductivity and restivity

Answer 38

measure of ability to conduct electric current

Question 39

dentin vs enamel conductor

Answer 39

dentin better for electricity

Question 40

carious teeth as conductors

Answer 40

less conductive

Question 41

Corrosion

Answer 41

deteriation by chemical or electrochemical rxn

Question 42

stimulants of corrosion

Answer 42

wet, salt, acids, warm, stress

Question 43

Anode

Answer 43

needed for corrosion; the surface where the corrosion occurs

Question 44

Cathode

Answer 44

needed for corrosion; where reduction rxns take place

Question 45

Electrolyte

Answer 45

needed for corrosion; a solution that conducts electricity-supplies the ions

Question 46

electromotive series

Answer 46

based on thermodynamics, ranking of relative corrosion resistance in metals; ideal in water and practical in Cl solns

Question 47

passivity

Answer 47

certain metals; limit corrosion, protects the metal or alloy from corrosion

Question 48

Electromotive series

Answer 48

resistance to corrosion

Question 49

uniform attack

Answer 49

corrosion all over

Question 50

Crevice Corrosion

Answer 50

i.e. oxygen depletion; results in specific areas of corrosion (think food on a restoration)

Question 51

Galvanic Corrsosion

Answer 51

when two metals are in physical contact (touching or soln between them) -Gold crown and amalgam in mouth; less noble (amalgam) will corrode and release ions

Question 52

Noble

Answer 52

higher (gold); protected from corrosion

Question 53

Anotic/Active

Answer 53

Low (mercury, silver, copper) will corrode and release ions

Question 54

Dental importance of corrosion

Answer 54

1. Harm a. think mercury-do not want released Allergens-nickel released palladium allergen too 2. esthetics compromised

Question 55

tarnish

Answer 55

surface discoloration which can be linked to corrosion

Question 56

other objects that tarnish

Answer 56

polymer materials