Tooth shade dxetermination

Dr. Borbély Judit

2018

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.

Evolution in dentistry – from manual treatment …

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… to digital processes

Evolution in shade taking

Evolution in shade taking – from visual shade taking …

Color is … a feature of an object

C4

A1

remission spectrum

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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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Ishihara-Test

The Ishihara test is a valid screening tool to test red-green-color deficiency.

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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

VITA classical A1-D4

reddish-brown reddish-yellow gray shades Reddish-gray

A B C D

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VITA Toothguide 3D-MASTER

bright dark

intensive

pale

yellowish reddish

1 2 3 4 5

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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)

Chroma

HUEthe color itself dependent upon wavelengthThe attribute of a color by which we distinguish red from green, blue from yellow, etc.

HUE

VITA Linearguide 3D-MASTER

Valueguide: all values with medium chroma and medium hue

5 Chroma/Hueguides 29 shade tabs = 3D-MASTER Toothguide

1. Value

2. Chroma/Hue

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

Dental spectrophotometer

Vita Easyshade dental spectrophotometer

Measure reflected wavelength

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Communication of color informations

Shade taking Color communication Color reproduction

How do i communicate

theinformations

?

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Communication of color informations

Color informations

Digital photography

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Lab technician requires adequat tooth color information to make a matching, lifelike restoration!

Best solution: several methods combined!

Thank You for Your Attention!