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
