Optical Properties Flashcards
Color is the border bw the ___ and ___
There should be ___ ____ dentistry
“Fcnal dentistry” should still be ____
Color is the border bw the esthetic and nonestheticThere should be no nonesthetic dentistry
“Fcnal dentistry” should still be esthetic
Rationale: Why study color in dentistry?
___
___
____
Rationale: Why study color in dentistry?
Clinical: It is our task
Scientific: We can make it better
Commercial
ΔE*
Change in ___
Not ___ to color and sight
There are ΔE* for___ too
If it equals 0, that is a ___ ___
ΔE*
Change in sensation
Not exclusive to color and sight
There are ΔE* for hearing too
If it equals 0, that is a perfect match
Perceptibility and Acceptability Thresholds
ΔE*= ___
50:50% perceptibility threshold, _____ for 50% of observers under controlled conditions
Perceivable difference by ½ of people
50% see the difference
ΔE*= ____
50:50% acceptability threshold, ____ for 50% of observers under controlled conditions
More-_____ than 1.2
We need to be within acceptable difference
___ the better
Perceptibility and Acceptability ThresholdsΔE*= 1.2
50:50% perceptibility threshold, detectable for 50% of observers under controlled conditions
Perceivable difference by ½ of people
50% see the difference
ΔE*= 2.7
50:50% acceptability threshold, acceptable for 50% of observers under controlled conditions
More important than 1.2
We need to be within acceptable difference
Smaller the better
Over ___% of patients were aware of the color difference between the____ and the adjacent ___ ___
Correct match ___ (2.7) of 16 pairs of tabs of 2 shade guides
People asked to match 16 pairs of 2 shade guides
Each shade guide has 16 tabs.
Take 16 from one and 16 from the other and match the pairs
The matched ½
Those that match 16/16
____
Able to participate in__ ___
An average shade matching error: __ Vita Shades
Over 80% of patients were aware of the color difference between the restoration and the adjacent natural teethCorrect match 7.7 (2.7) of 16 pairs of tabs of 2 shade guides
People asked to match 16 pairs of 2 shade guides
Each shade guide has 16 tabs.
Take 16 from one and 16 from the other and match the pairs
The matched ½
Those that match 16/16
Competent
Able to participate in color research
An average shade matching error: 4.0 Vita Shades
Shade matching reproduction of ceramic disks–>monochromatics
Vitspan Classical/VMK 68- ΔEab = ___
This is over the accepted value
ShadeEye-EX/Vintage Halo- ΔEab = ___
Vitaspan 3-D Master/Omega 900- ΔEab =___
Shade matching reproduction of ceramic disksà monochromaticsVitspan Classical/VMK 68- ΔEab = 3.5
This is over the accepted value
ShadeEye-EX/Vintage Halo- ΔEab = 4.5
Vitaspan 3-D Master/Omega 900- ΔEab = 6.8
An average ΔEab = ___ was recorded among metal ceramic crowns made by two operators
Two technicians in the same room making the same thing
Tooth before preparation and crown before cementation: ΔEab = ___
Scary!
That is why all white is so safe, you can’t make a mistake
An average ΔEab = 3.6 was recorded among metal ceramic crowns made by two operators
Two technicians in the same room making the same thing
Tooth before preparation and crown before cementation: ΔEab = 10.5
Scary!
That is why all white is so safe, you can’t make a mistake
The field of esthetic dentistry has exploded in the last few years. Some 15 years ago, esthetic dentistry accounted for less than ___% of the money spend on dental care, now it exceeds __%.
Commercial
We are not all gifted for shade matching
Only __% are
The field of esthetic dentistry has exploded in the last few years. Some 15 years ago, esthetic dentistry accounted for less than 20% of the money spend on dental care, now it exceeds 70%.
Commercial
We are not all gifted for shade matching
Only 16% are
Psychophysics
Scientific discipline dealing with ____ relations between ___ ___i and ____s they cause
Psychophysics
Scientific discipline dealing with mathematical relations between physical stimuli and sensations they cause
Colorimetry
____ of color based on a __ of ____
Color is not trivial addition or subtraction
Colorimetry
Measurement of color based on a set of conventions
Color is not trivial addition or subtraction
Color
___ ___ provoked in the___ by the__ ___ and interpreted by the ___
Brain tells us based on our stored memory what we ___ we see.
We look at the light ____ from the tooth
ColorPsychophysical sensation provoked in the eye by the visible light and interpreted by the brain
Brain tells us based on our stored memory what we think we see.
We look at the light reflected from the tooth
Visible part of the spectrum: 400-700 nm
This is all we see
Visible part of the spectrum: 400-700 nm
This is all we see
Light Source
Any___or ___y ___ ____in the ___ ___ range
Light Source
Any area or body emitting radiation in the visible spectra range
Primary
Lamp
Secondary
Tooth
Light comes to our eyes from the tooth
Natural
Sun
Artificial
Any other
Three things that define any color
___ ___ ___
A spectral characteristic of the ___ ___ ___ heated to a +__ ____ and expressed in _.
Daylight: ___
___ ___ ___ (CRI)The___ scale is used to show the relation bw the ___ and the___ light source (CRI=___)
How well does it represent ideal light
100 is ___
__ and above is what you want for dental shade matching
__ ___ ____ (SED)
Color “___” represented by __ ___
Three things that define any colorCorrelated Color Temperature
A spectral characteristic of the black body radiator heated to a certain temperature and expressed in K.
Daylight: D65
Color Rendering Index (CRI)The 0-100 scale is used to show the relation bw the examined and the standard light source (CRI=100)
How well does it represent ideal light
100 is perfect
90 and above is what you want for dental shade matching
Spectral Energy Distribution (SED)
Color “fingerprint” represented by reflection curve
Standard Light sources are
A:
B:
C
D65: daylight
Standard Light sources are
A:
B:
C
D65: daylight
- When light strikes a surface, the change in___ ___can cause light to be ____ by the surface antr-=d/or p___ the ___y of the material
- Reflection:
- Process by which ___ is ___ by a surface, ___ reflection or a ___-___ reflection
- Volume reflection
- Teeth are not transparent. They are ____ so some light will get refracted.
- Light travels further than the surface of the tooth
- Sometimes all the way to dentin
- Dentin is more ___ (opaque) so majority of light is reflected from it
- Reflection from the ___
- Sometimes all the way to dentin
When light strikes a surface, the change in refractive index can cause light to be reflected by the surface and/or penetrate the body of the material
Reflection:
Process by which radiation is returned by a surface, surface reflection or a medium-
Volume reflection
Teeth are not transparent. They are translucent so some light will get refracted.
Light travels further than the surface of the toothSometimes all the way to dentin
Dentin is more colored (opaque) so majority of light is reflected from it
Reflection from the inside
- …≥÷Angular Distribution+
- ____l reflection + ___ reflection= total reflection
- Spectral Reflection: ____ reflection
- The same but opposite angle
- In dentistry we call this ___
- Shiny teeth
- ____e Reflection
- Any ___ ___of reflection
Angular Distribution
Spectral reflection + diffuse reflection= total reflection
Spectral Reflection: mirror reflection
The same but opposite angle
In dentistry we call this gloss
Shiny teeth
Diffuse Reflection
Any other angle of reflection
- àsz1`m v\
- ,Absorption
- The phenomenon in which light is ___ ___ or ___ by the object
- Transparency
- ____ of light____ an object with___ ____
- Ex) ___ ____
- ____
- Translucency
- ___ of light permitted but light is ____
- Ex) ___ ____, ___
- Light ____ so its not really clear
Absorption
The phenomenon in which light is absorbed fully or partially by the object
Transparency
Passage of light thru an object with little distortion.
Ex) Incisal porcelain
Clear
Translucency
Passage of light permitted but light is distorted
Ex) Body Porcelain, Composite
Light changes so its not really clear
Opacity
Optical property that ___ ___ of ____
Opaque medium is the medium that ___ __ ___ in the __ __ of ____
Ex)___ ____
Opposite of____
Absolute opacity is _ translucency and vise versa
Opacity
Optical property that prevent passage of light
Opaque medium is the medium that transmit no radiation in the spectral range of interest
Ex) Opaque Porcelain
Opposite of translucency
Absolute opacity is 0 translucency and vise versa
Fluorescence
Process by which___, usually ___, is ___ by certain chemicals or materials and ____ at other, usually ____ wavelengths
Property of our dental tissue and materials
Fluorescence
Process by which Energy, usually UV, is absorbed by certain chemicals or materials and re-emitted at other, usually longer wavelengths
Property of our dental tissue and materials
Opalescence
The material appears _______ in ____ light and___ in ____ light perpendicular to the____ light
Opalescence
The material appears yellowish-red in transmitted light and blue in scattered light perpendicular to the transmitted light
Eye: All visually sensations are brought to the brain through the ___
Eye: All visually sensations are brought to the brain through the eye
Retina
A complex mosaic of millions of ___ ____
Rods only record ___
They see in black and white
Cones: Nerve endings that enable __ ___
Sensitive to
Blue
Green
Red
Retina
A complex mosaic of millions of nerve endings
Rods only record light
They see in black and white
ConesNerve endings that enable color visionSensitive to
Blue (S)
Green (M)
Red (L)
Brain
On reaching the brain, the ____, the messages from rods and cones will connect the picture ____ with something ___ ___.
Brain
On reaching the brain, the interpreter, the messages from rods and cones will connect the picture presented with something previously experienced
Females are better ___ ___ than men
Color Deficiency
A ____ hereditary color vision disorder that occurs as a consequence of abnormality on __ csome.
Women___ and men ___ color deficiency
__ of males
__ of females
- Need __ ___to be color deficient
Among color normal individuals, there is __ ___ bw __ and ___
No one is color blind unless they are blind. We all see colors. Some people are deficient
Females are better shade matchers than men
Color Deficiency
A recessive hereditary color vision disorder that occurs as a consequence of abnormality on X csome.
Women bring and men inherit color deficiency
8% of males
0.5% of females
Need both parents to be color deficient
Among color normal individuals, there is no difference bw males and females
No one is color blind unless they are blind. We all see colors. Some people are deficient
Computer simulation
Allows us to compare how a normal person would see colors vs. people deficient is R G or B
____ L: Red deficiency
___: M: Green deficiency
____: S: Blue deficiency
__ and ___deficiencies look similar
Computer simulation
Allows us to compare how a normal person would see colors vs. people deficient is R G or B
Protanope: L: Red deficiency
Deuteranope: M: Green deficiency
Tritanope: S: Blue deficiency
Red and Green deficiencies look similar
Chromatic Adaptation
The inability of ___ the color of the ___ scene when the ___ ___ is ___
Chromatic Adaptation
The inability of changing the color of the viewed scene when the light source is changed
Metamerism: 4 definitions and they are all correct:
Change of __ ___ of 2 objects viewed under ___ ___sources
Two color samples appear to ___ ___ ___ ____ but not under another
____match: They look the same under one light and look different under a different light
______match
____: The opposite
- ____match
- They are the ___ thruout the visible spectra range
Metamerism4 definitions and they are all correct:
Change of color matching of 2 objects viewed under different light sources
Two color samples appear to match under one condition but not under another
Conditional match: They look the same under one light and look different under a different light
Non-spectral match
Isomerism: The opposite
Unconditional match
They are the same thruout the visible spectra range
Dichroism
Refers to a situation when the color of an object, viewed by ____ light may be different according to the____ of the sample viewed (blood, water..)
Thickness is the essence of color reproduction
Dichroism
Refers to a situation when the color of an object, viewed by transmitted light may be different according to the thickness of the sample viewed (blood, water..)
Thickness is the essence of color reproduction
- Primary Colors
- __
__
__
- __
- Secondary Colors
- The ___of any ___ __ ___
- Yellow:
- Cyan:
- Magenta:
- Complementary Colors
- ___on the ___ sides of the color wheel
- Used extensively
- Shades
- Colors with ___ of ___ added to a__ __
Primary Colors
Red
Green
Blue
Secondary Colors
The blend of any two primary colors
Yellow: Red and green
Cyan: Blue and green
Magenta: Blue and red
Complementary Colors
Hues on the opposing sides of the color wheel
Used extensively
Shades
Colors with quantum of black added to a base color
- Additive mixture
- Mixing of colored ____
- The mixture results in the occurrence of ___
- Subtractive mixture
- Mixing of colored substances and ___
- The mixture results in the occurrence of ___
Additive mixture
Mixing of colored lights
The mixture results in the occurrence of white
Subtractive mixture
Mixing of colored substances and pigments
The mixture results in the occurrence of black
Visual Comparison
A comparison with some known ___ ___ accepted as ___
___ Book of Color
Dental ____ ____
Visual Comparison
A comparison with some known physical standard accepted as referral
Munsell Book of Color
Dental Shade Guides
Color measuring instruments
Designed to overcome ____, the major drawback of ___ ___ ____
Parameters that have to be defined
___ ___
___ ___ ____
___ ____
___ ___
Instruments are designed response on the reaction of the human eye
Color measuring instruments
Designed to overcome subjectivity, the major drawback of visual shade matching
Parameters that have to be defined
Light source(s)
CIE standard observer(s)
Optical geometry(s)
Colorimetric System(s)
Instruments are designed response on the reaction of the human eye
Optical GeometryBroken down into:_____t Geometry
First number is always ____ geometry
____ geometry
Optical GeometryBroken down into:Illuminant Geometry
First number is always illuminant geometry
Viewing geometry
Hue (H): ___ ___
Dimension that enables differentiation between ___ ___
Placed in a closed __ ___
360 degrees
Different degree means different color
Hue (H): Color Name
Dimension that enables differentiation between color families.
Placed in a closed hue circle
360 degrees
Different degree means different color
Value (V): __ ___
Value or ____ is a dimension that enables discrimination between___and ____ color and is represented as a _______
Black (___) to white (___) with many shades of grey in bw
Value (V): No color
Value or lightness is a dimension that enables discrimination between light and dark color and is represented as a black-white axis
Black (bottom) to white (top) with many shades of grey in bw
Chroma (C): ___ ____
Enables differentiation between __ and __colors
Presented as the distance from the ____ (___ axis)
Pale to strong
Same color but differ intensity
Close to center is ____
Farther out:___
Chroma (C): Color Strength
Enables differentiation between pale and strong colors
Presented as the distance from the vertical (achromatic axis)
Pale to strong
Same color but differ intensity
Close to center is pale
Farther out: stronger
CIELAB system Color coordinates:
L* :
____, ___
a*
____
b*
_____
C*
___
H°
___
H and C are calculated mathematically from_____
Color difference between the compared colors is expressed in ____ units and it represents the ___ ___ __ ___ ___ ____ ((_ _ _ or _ _ _°)
CIELAB system Color coordinates:
L* :
Lightness, black-white
a*
green-red
b*
blue-yellow
C*
Chroma
H°
Hue
H and C are calculated mathematically from a and b
Color difference between the compared colors is expressed in ΔE* units and it represents the sum of all coordinate color differences ((L*, a*, b* or L*, C*, H°)
Munsell System
Not used anymore because of problems with numbers
But it is the same
Black to white
Different hue
Different chroma
Munsell System
Not used anymore because of problems with numbers
But it is the same
Black to white
Different hue
Different chroma
