Fixed Exam 2 - Color Flashcards
A phenomenon of light or visual perception that enables one to differentiate otherwise identical objects
Color
A visual response to light consisting of the 3 dimensions of hue, value, and chroma
Color
What are the 3 variables of color?
Receptor (eye)
Object
Light source
Which variable of color?
Color blindness, color perception deficiency
Receptor (eye)
Which variable of color?
Absorbs, reflects, and/or refracts light
Object
Which variable of color?
Wavelength of light
Light source
Internationally accepted standard of art, science, and industry
Munsell color space
T/F: In the 40’s, the Munsell color system was revised by International Commission of Illumination (CIE) and American Society for Testing and Materials
True
Band of colors produced when sunlight is passed through a prism
Spectrum
What are the primary additive colors?
Red
Green
Blue
What are the secondary additive colors?
Magenta
Yellow
Cyan
If the 3 primary colors are combined with equal intensities, what type of light is created?
White light
A number from 1-100 given to a light source to indicate its relative equivalence to pure white light, which has a color rendering index (CRI) of 100
Color rendering index
The closer the number is to 100, the more it resembles pure ________ light
white
A light source with at least ________ CRI is recommended for an accurate shade selection
93.42
Often referred to as the basic color
Hue
It is the quality of sensation according to which an observer is aware of the varying wavelengths of radiant energy
Hue
The dimension of color dictated by the wavelength of the stimulus that is used to distinguish one family of color from another - as red, green, blue, etc
Hue
White, black, and gray possess no _______
hue
The color itself
Hue
The attribute of a color by which we distinguish red from green, blue, yellow, etc
Hue
What can be used to change the hue of porcelain (yellow, red, etc)?
Stains
The purity of a color, or its departure from white or gray
Chroma
The intensity of a distinctive hue; saturation of a hue
Chroma
Describes the strength or saturation of the hue
Chroma
The intensity of a color
Chroma
High or low chroma?
Highly saturated
High chroma
High or low chroma?
Weakly saturated
Low chroma
The quality by which a light color is distinguished from a dark color, the dimension of a color that denotes relative blackness or whiteness
Value
Only dimension of color that may exist alone
Value
The brightness of a color
Value
High or low value?
Brighter (more white)
High value
High or low value?
Darker (more gray)
Low value
What is the value?
Black
Value = 0
What is the value?
White
Value = 10
What is the most important color variable in dental shade selection?
Brightness
What is the most important aspect in shade selection?
Value
If a complementary color is used to modify a color, what will happen?
It’s value will decrease
What factors cause color to appear different?
Light source
Size/contours
Background color + lighting
Perception angle
Convey shades of gray (value)
Rods
Allow brain to perceive hue and chroma
Cones
Rate of color blindness in females
1 in 300
Rate of color blindness in males
1 in 13
Everything we see is __________ light
reflected
What is required to see real color?
Full spectrum
T/F: Color won’t be able to be seen if light cannot be reflected
True
What is the illumination of daylight?
6500 K
What is the illumination of electronic flash?
5500 K
What is the illumination of standardized light source?
5000 K
(CRI = 98)
What is the recommended illumination for accurate shade selection in dentistry?
5500 K
CRI above 93.42
Working distance (12-15 inches; arm’s length)
Op painted w/ neutral colors
Which illumination?
Replicates northern natural midday daylight and balances all hues in the spectrum curve
5500 K
A phenomenon where teeth appear to be the same color under one type of light, but they appear different under another light source
Metamerism
__________ light sources is recommended for shade selection, so an ideal CRI is obtained.
(sunlight should be one of them, most importantly)
Multiple
Staining of porcelain will increase ____________ responses
metameric
Light source affects the _____________ of color, because the light source must contain the wavelength of the color to be matched in order to see that color
perception
What device has the following light modes?
Color-corrected light 5500°K (daylight)
Incandescent 3200°K (room light)
Ambient light 3900°K (combination of room light and daylight)
Rite Lite 2
Which device?
Magnetic polarized filter eliminates reflections the teeth, which may obscure details
Rite Lite 2
Which device?
Determines tooth shade in accordance to the Vita Classical shade guide (A1-D4)
Vita Easyshade Advance
The light effect of a translucent material (incisal edge of some teeth) appearing blue in reflected light and red-orange in transmitted light
Opalescence
The optical property by which a material reflects UV radiation
Fluorescence
The energy the tooth absorbs is converted into light with longer wavelengths, in which the tooth actually becomes a source of light
Fluorescence
Human teeth fluoresce mainly __________ hues
blue-white
Makes a definite contribution to the brightness and vital appearance of natural teeth
Fluorescence
Property of a material that absorbs and/or reflects all light and prevents any transmission of light
Opaque
Having the appearance btwn complete opacity and complete transparency
Translucency
Partially opaque
Translucency
Shade guide to identify the shade of the
preparation supporting the future
restoration
Stump shade guide
Essential when working with translucid materials (lithium dislicate or feldspathic
restorations)
Stump shade guide
ALWAYS use this guide when working on esthetic cases
Stump shade guide
T/F: Lab techs modify the restoration’s shade to mask the underlying preparation’s shade
True
Reddish-brownish
A
Whitish-yellowish
B
Greyish
C
Reddish-gray
D
When should you select shade? Why?
At beginning of appointment
Teeth dehydrate, which will alter shade selection
How far should you be from the pt’s teeth when selecting shade?
12-15 inches
The patient’s ________ and clinician’s _______ should be at the same level
teeth; eyes
You should judge the shade with a quick gaze. Why?
Cones fatigue quickly
How many shades should you select?
2-3, and then involve pt for final shade selection
Why should you take photos?
Better communication w/ lab
Pictures should be taken ___________ to teeth
perpendicular
Angle the camera slightly up or down to avoid _________ of teeth or tab
reflection
When taking photos, you want to show at least _________ teeth
6-8
The _____________ surface of tab and teeth should be on the same plane. Light will reflect in a similar way
facial
Hold the tab close to teeth but not in contact. Contact may interfere with what?
Incisal edge translucency
If multiple shades are required, only use _____ shade per picture to avoid distraction. Take multiple pictures for each shade!
1
T/F: If you are trying in a restoration and the shade needs to be modified, follow the same instructions, but with the restoration in place
True
T/F: Remember Dual-Cure and Chemical-Cure cements can change shade over time. Avoid them for esthetic cases!
True
