SHADE MATCHING . PPTS By M. Swathi

SHADE MATCHING.pptx

1. A HINT FROM TINT DIGITAL SHADE MATCHING

2. Contents

3. INTRODUCTION Esthetics has gained wide importance over the last few years among both dental practitioners and patients. It is essential to deliver an esthetic restoration that symmetrically blends with the patient's adjacent teeth 

4. Many prostheses fail due to improper shade selection, and therefore, every dentist should be acquainted with the shade selection process to achieve the best outcomes. Human dentition shades differ significantly, and electronic devices can identify approximately 100,000 dental shades while the human eye can identify only 1% of these shades.

5. COLOR SCIENCE Colour is perceived when human eye using two sensory structures[ rods,cones ] receives visible light wavelengths In the context of clinical dentistry, for colour to exist there must be a source [light], an object [teeth] and receptor [eye].

6. Type and quantity of illumination

7. Metamerism

8. CONTRAST • Contrast is an important consideration in shade selection. Contrast is the opposition(resisting) or juxtaposition(state of being close) of different forms, lines, or colors. • Items such as wall color, bib color, lipstick, and inflamed gingival tissues can all affect the clinician’s ability to accurately assess the color of a restorative material. .

9. Three dimensions of color Hue describes the dominant shade of the tooth (more yellowish or reddish). Value is the lightness or darkness of the tooth shade measured independently of the hue. Chroma is the saturation, intensity or strength of the Hue

10. MEASUREMENT OF COLOR Color determination in dentistry can be divided into two categories: Visual Instrumental

11. Visual technique : A popular system for visual determination of color is the Munsell color system, the parameters of which are represented in three dimensions . Value (lightness) is determined first by the selection of a tab that most nearly corresponds with the lightness or darkness of the color. Chroma is determined next with tabs that are close to the measured value but are of increasing saturation of color. Hue is determined last by matching with color tabs of the “value” and “chroma” already determined.

12. Visual shade guides

13. Shade selection The patient should be viewed at the eye level so that the most color-sensitive part of the retina will be used. Shade comparison should be made under different lighting conditions. Normally, the patient is taken to a window and the color is confirmed in natural daylight after initial selection under incandescent and fluorescent lightening. The teeth to be matched should be clean,shade comparison should be made at the start of the patient visit. Brightly colored clothing should be draped and lipstick should be removed. Shade comparison should be made quickly, with the color samples placed under the lip directly next to the tooth being matched. The eye should be rested by focusing on a gray-blue surface immediately before a comparison since this balances all the color sensors of the retina and resensitizes the eye to the yellow color of the tooth.

14. DRAWBACKS Visual determination of shade selection has been found to be unreliable and inconsistent. Visual color assessment is dependent on the observer’s physiologic and psychologic responses to radiant energy stimulation. Inconsistencies may result from uncontrolled factors such as fatigue, aging, emotions, lighting conditions, previous eye exposure, object and illuminant position and metamerism

15. Instrumental technique In this system, the color space consists of three coordinates: L*, a* and b* . The L* refers to the lightness coordinate, and its value ranges from 0 for perfect black to 100 for perfect white. The a* and b* are the chromaticity coordinates in the red–green axis and yellow–blue axis, respectively. The differences in the lightness and chromaticity coordinates (∆L*, ∆a*, ∆b*) as a result of UV light exposure are determined first, and the total color change (∆E* ab ) can be calculated using the relationship

16. All color-measuring devices comprise three parts: A detector, signal conditioner, and software that converts the signal into data that can be used in the dental laboratory or operatory. Following are examples of color measuring instruments: (1) colorimeters, (2) spectrophotometers, (3) digital cameras, (4) hybrid devices, and (5) spectroradiometers. Color measuring instruments

17. Filter colorimeters generally use three or four silicon photodiodes that have spectral correction filters, which act as analog function generators that limit the spectral characteristics of the light striking the detector surface. The filter colorimeters are considered inferior to scanning devices such as spectrophotometers and spectroradiometers because of the inability to match the standard observer functions. However, because of their consistent and rapid sensing nature, these devices can be used for quality control. ShadeEye is an example of a colorimeter based on the natural color concept Colorimeter

18. It is a photometer that can measure intensity based on color, or more specifically, wavelength. The optical elements consist of a light source, monochromator, and detector. In general, light sources are diffracted. Several wavelengths are passed through the entrance slit and test sample to be tested . Different wavelengths of light are selectively absorbed by the sample. The light then passes through another slit, called the exit slit, and strikes the detector. The detector converts the intensity of light at a certain wavelength into an electrical signal, which is then amplified and displayed on a screen or plotted on a chart. Spectrophotometer VITA Easyshade ® V

19. Instead of focusing light on the film to create a chemical reaction, digital cameras capture images using charged coupled devices. To get a full color image, most sensors use filtering to look at the light in its three primary colors in a manner analogous to the filtered colorimeter. Light is directed to the different filter/sensor combinations by placing a beam splitter in the camera. The beam splitter allows each detector to see the image simultaneously. The advantage of this method is that the camera records each of the three colors at each pixel location. DIGITAL CAMERAS SpectroShade

20. The phenomenon of edge loss affects the accuracy of color measurement; Translucent mapping is inadequate for all systems; The laboratory must have up-to-date systems for the successful application of this approach; This approach requires a relatively expensive setup

21. REVIEW OF LITERATURE

22. Conclusion Selection of the correct shade is the foundation for superior esthetics. Determining and closely reproducing the appearance and form of teeth is challenging. To provide an esthetic restoration to the patient, the dentist must have a full understanding of the science of color and color perception. Matching the correct shade satisfies both the dentist and patient and gives a pleasing appearance to the patient. In order to achieve good esthetics, both conventional and digital shade systems should be employed during the shade selection process.

23. References Repeatability and reliability of human eye in visual shade selection. Özat PB, Tuncel İ, Eroğlu E. J Oral Rehabil . 2013;40:958–964.   Shade selection. Basavanna R, Gohil C, Shivanna V. Int J Oral Health Sci. 2013;3:26–31.  Role of colors in prosthodontics: application of color science in restorative dentistry. Bhat V, Prasad DK, Sood S, Bhat A. Indian J Dent Res. 2011;22:804–809.

24. Borse S, Chaware SH. Tooth shade analysis and selection in prosthodontics: A systematic review and meta-analysis. The Journal of Indian Prosthodontic Society. 2020 Apr 1;20(2):131-40. Wyszecki G, Stiles WS. Color Science: Concepts and Methods, Quantitative Data and Formulae. 2nd ed. New York: John Wiley; 1982.p. 83-173. Rashid F, Farook TH, Dudley J. Digital Shade Matching in Dentistry: A Systematic Review. Dent J (Basel). 2023 Oct 27;11(11):250. doi : 10.3390/dj11110250. PMID: 37999014; PMCID: PMC10670912.

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