Tooth shade determination - Semmelweis Egyetem
Transcript of Tooth shade determination - Semmelweis Egyetem
The American Academy of Cosmetic Dentistry completed a study regarding tooth brightness and appearance. An overwhelming majority (90 percent) of those surveyed viewed people with whiter teeth as healthier and more attractive,” In fact, further studies by the American Academy of Cosmetic Dentistry show that 96 percent of adults believe an attractive smile makes a person more appealing to the opposite sex, and 74 percent of adults feel an unattractive smile can hurt a person’s chances for career success.
Color is… an interaction between the object and its illumination
TL84
D55
illumination spectrum
!! Metamerism !!
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Quelle: sikkens AkzoNobel
Metamerism
Two objects may generate the same color impression under one illumination but a different color impression under a second illumination
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Color is … dependent on the observer
Red receptor green receptor blue receptor
Human eyes comprise app. 8Mio. receptors being sensitive for red, green or blue. Superposition of these 3 channels leads to the capability to differentiate app. 7Mio. color impressions.
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Color is … dependent on the observer
Color perception is also influenced by the observer´s aperture angle (i.e. distance to the eye)
Spectral sensitivity for aperture angle 2° (white) and 10° (black)
Red receptor green receptor blue receptor
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Predictable esthetic results- combine methods!
Ø Visual shade selectionØ Shade measurement
Shade selection
Chu SJ, Trushkowsky RD, Paravina RD. (2010) Dental color matching instruments and systems. Review of clinical and research aspects. J Dent, 38 Suppl 2: 2-16.
Shade tabs:• No of tabs:
too many-tyringnot enough-no match
Visual color match
• Vita-Vita testEvaluation of visual and instrument shade matchingScott R. Okubo, School of Dentistry, West Virginia University Morgantown, J Prosthet Dent 1998;80:642-648
CIE Lab tooth color spaceGrassmann/ Munsell:Value degree of lightness or darkness of a color relative
to a series of grays Chroma the difference between the color and a gray
having the same brightnessHue physical wavelength of light, represented as an angle
ranging from 0° to 360°.
VALUE
Chroma
Value:
The proper Value is the most important dimension in the shade determining process!Black GV. A work on operative dentistry. Chicago: Medico-Dental Pub Co; 1908. p. 347.
brightness of the color (high value-brighterlower value-darker)
Chromaintensity, saturation, purity of the color (low chroma=weak,high chroma=highly saturated, pure colors)
HUEthe color itself dependent upon wavelengthThe attribute of a color by which we distinguish red from green, blue from yellow, etc.
VITA Linearguide 3D-MASTER
Valueguide: all values with medium chroma and medium hue
5 Chroma/Hueguides 29 shade tabs = 3D-MASTER Toothguide
Shade selection keys• Use correct environment and
lightning• Select shade at the beginning of
appointment• Patient sitting upright• Patient’s teeth/dentist’s eyes at
same level• Look for variance between gingival
,middle and incisal thirds of teeth• Must surround teeth with colour
that aids color perception• Use neutral colors in operatory• Window light-daylight• No lipstick• Always use a bibCover brightly-colored clothingNatural teeth-orange/compliment of
orange is blueUse gray patient bibs
Digital Tooth Shade Determination
Spectrophotometer: Easyshade Compact, VitaShadepilot, Degudent
Colorimeter: ShadeEye SHOFU Inc., JapanDigital Shade Guide DSG 4 PLUS, Rieth
RGB device: ShadeScan, Cynoprod, CanadaShadeVison System, x-rite
RGB DevicesColorimeterSpectrophotometer
Communication of color informations
Shade taking Color communication Color reproduction
How do i communicate
theinformations
?
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Lab technician requires adequat tooth color information to make a matching, lifelike restoration!
Best solution: several methods combined!