Tooth shade dxetermination. Dr. Borbély Judit

Transcription

1 Tooth shade dxetermination Dr. Borbély Judit 2018

2 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.

3 Evolution in dentistry from manual treatment

4 to digital processes 4

5 Evolution in shade taking

6 Evolution in shade taking from visual shade taking

7 Color is a feature of an object remission spectrum A1 C4 13

8 Color is an interaction between the object and its illumination illumination spectrum D55 TL84!! Metamerism!! 14

9 Metamerism Two objects may generate the same color impression under one illumination but a different color impression under a second illumination Quelle: sikkens AkzoNobel 15

10 Color is dependent on the observer 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. Red receptor green receptor blue receptor 16

11 Color is dependent on the observer Color perception is also influenced by the observer s aperture angle (i.e. distance to the eye) Red receptor green receptor blue receptor Spectral sensitivity for aperture angle 2 (white) and 10 (black) 17

12 Ishihara-Test The Ishihara test is a valid screening tool to test redgreen-color deficiency. 18

13 Shade selection Ø Visual shade selection Ø Shade measurement Predictable esthetic results- combine methods! 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.

14 Visual color match Shade tabs: No of tabs: too many-tyring not enough-no match Vita-Vita test Evaluation of visual and instrument shade matching Scott R. Okubo, School of Dentistry, West Virginia University Morgantown, J Prosthet Dent 1998;80:

15 CIE Lab tooth color space Grassmann/ 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 brightness Hue physical wavelength of light, represented as an angle ranging from 0 to 360. V A L U E Chroma

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18 VITA classical A1-D4 A B C D reddish-brown reddish-yellow gray shades Reddish-gray 33

19 VITA Toothguide 3D-MASTER bright dark pale intensive yellowish reddish 37

20 Value: brightness of the color (high value-brighter lower value-darker) 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; p. 347.

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22 Chroma intensity, saturation, purity of the color (low chroma=weak, high chroma=highly saturated, pure colors)

23 Chroma

24 HUE the color itself dependent upon wavelength The attribute of a color by which we distinguish red from green, blue from yellow, etc.

25 HUE

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27 VITA Linearguide 3D-MASTER Valueguide: all values with medium chroma and medium hue 5 Chroma/Hueguides 29 shade tabs = 3D-MASTER Toothguide

28 1. Value

29 2. Chroma/Hue

30 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 bib Cover brightly-colored clothing Natural teeth-orange/compliment of orange is blue Use gray patient bibs

31 Digital Tooth Shade Determination RGB Devices Colorimeter Spectrophotometer Colorimeter: ShadeEye SHOFU Inc., Japan Digital Shade Guide DSG 4 PLUS, Rieth RGB device: ShadeScan, Cynoprod, Canada ShadeVison System, x-rite Spectrophotometer: Easyshade Compact, Vita Shadepilot, Degudent

32 Dental spectrophotometer

33 Vita Easyshade dental spectrophotometer

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36 Measure reflected wave length

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43 Communication of color informations Shade taking Color communication How do i communicate the informations? Color reproduction 51

44 Communication of color informations Color informations Digital photography 52

45 Best solution: several methods combined! Lab technician requires adequat tooth color information to make a matching, lifelike restoration!

46 Thank You for Your Attention!