shade selection


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1 : SHADE SELECTION GUIDED BY – DR. Manoj Chandak H.O.D. Prof & Guide DR. N.U.Manwar Prof. DR. P. Nikhade Assot. Prof DR. Ajay Saxena Assot. Prof. PRESENTED BY – DR. Ayan Das pg student
2 : INTRODUCTION If the petal of rose are pink and there are no one to view them, are they actually pink? According to color theorist the answer is NO. the reason of this surprising answer is that in order to color exist, there needs to be an interaction between three elements : light, an object, and a viewer. If the three elements are not present there is no exsisitent of color. Its best describe as abstract science. Color appeals to the visceral and emotional sences.
3 : Color Influenced by three main factors 1. Physical properties of the object 2. Assessment of the observer 3. Nature of incident light Relationship to other colored objects
4 : Light Part of the electromagnetic spectrum The eye is only sensitive to the visible portion of the spectrum (380 – 750nm) Different wavelengths constitute the different colors we perceive
5 : Pure White Light Relatively equal quantities of electromagnetic energy over the VLS When passed through a prism we see component colors of white light Shorter wavelengths bend more than longer wavelengths 380nm 750nm + + + + + + =
6 : Quality of Light / 3 Types Incandescent Light Fluorescent Light Natural Daylight Most dental offices are outfitted with incandescent and fluorescent lights
7 : Color Rendering Index CRI = (0-100) Indicates how well a light source renders color as compared to a standard source (N. Daylight) Northern daylight (hence CRI) can be affected by Time of day Cloud cover Humidity Pollution
8 : CRI and Time of Day Morning and evening Shorter wavelengths scatter before penetrating atmosphere Daylight rich in yellow/orange, lacks blue/green Mid-day Hours around noon = ideal Incident daylight is most balanced within VLS Full spectrum of colors visible
9 : Color Temperature Another light source reference standard Related to the color standard black body when heated Reported in degrees Kelvin (°K) 1000K – red 2000K – yellow 5555K – white 6500K – northern daylight 8000K – pale blue Dependent on four factors which influence CRI
10 : 1. Incandescent Light Emits high concentration of yellow waves Not suitable for shade matching Low Color Rendering Index (CRI)
11 : 2. Fluorescent Light Emits high concentration of blue waves Not suitable for shade matching CRI =(50-80)
12 : 3. Natural Daylight Northern daylight considered the best Closest to emitting the full spectrum of white light Used as the standard by which to judge other light sources CRI close to 100
13 : Color The quality of an object or substance with respect to light reflected by the object, usually determined visually by measurement of hue, chroma and value
14 :
15 :
16 : Munsell Atlas Courtesy Gretag-Macbeth
17 : Primary Colors Red, blue, and yellow comprise the three primary colors. These three colors can approximate, through selective mixture, all of the other colors.
18 : Secondary Colors Orange, violet, and green are the secondary colors. Each is placed between the two primaries that are mixed to produce it.
19 : Primary & Secondary Colors
20 : Subtractive Color These are the colors associated with the subtraction of light Used in pigments for making paints, inks, fabrics etc. The primary subtractive colors are Red, Yellow, and Blue The secondary subtractive colors are Green, Purple and Orange When subtractive primary colors are combined they produce black
21 : Additive Color These are the color obtained by emitted light Associated with television and computer displays The primary additive colors are Red, Blue and Green The secondary colors are Cyan, Yellow and Magenta When additive primary colors are combined they produce white
22 : Complimentary Colors
23 : Three Attributes of Color Hue Chroma Value
24 : Hue Variety of color (red, green, yellow, etc.) Determined by wavelength of observed light within the VLS Reflected wavelength determines hue
25 : Hue Hue identifies a color by name. Every color falls into a definite hue category as indicated by the spectrum color name on the color wheel.
26 : Chroma The intensity or saturation of a hue Low Chroma High Chroma
27 : Chroma Chroma refers to the degree of intensity, strength, saturation, or purity of a color. Purity of a color refers to its freedom from white, black, or gray.
28 : Value The relative darkness or lightness of a color, or brightness of an object Range = 0-10 (0=black, 10 = white) Amount of light energy an object reflects or transmits Objects of different hues / chroma can be identical value Restorations too high in value are easily detected High Value High Value Low Value
29 : Value White added to a hue creates a tint. Gray added to a hue creates a tone. Black added to a hue creates a shade. Value is the lightness or darkness of a hue achieved by adding white, gray, or black.
30 : Objects of different chroma / hue can be identical value
31 : - Equal in Chroma / Variation in Value - Variation in Chroma / Equal in Value Value
32 : Objects of different chroma / hue can be identical value
33 : Visual System Light path Cornea, pupil, lens, retina, optic nerve, brain Retinal cells Rods and cones Unevenly distributed Cones Three “color receptors” Concentrated in fovea
34 : Perception of Color
35 : Color Perception Rods Scotopic (gray scale) vision, interpret brightness Interpret brightness, not color Highest concentration on peripheral retina Cones Photopic (color) vision Interpret color More active under high light Highest concentration on central retina (macula), most color perceptive area of eye
36 : Color Adaptation Color vision decreases rapidly as object is observed Color viewed dulls, while its compliment increases in intensity Fatigue Viewing a pale blue or gray surface between shade matching will restore color vision
37 : Cone Response Encode spectra as three values Long, medium and short (LMS) Trichromacy From A Field Guide to Digital Color, © A.K. Peters, 2003
38 : Effects of Retinal Encoding All spectra that stimulate the same cone response are indistinguishable Metameric match
39 : Metamerism Two colors that appear to be a match under a given lighting condition but have different spectral reflectance = metamers, the phenomenon is metamerism. Light Source #1 Single Light Source Light Source #2 Light Source #3
40 : METAMERISM
41 : Color Blindness Defect in color vision 8% males 0.5% females Several variations exist Achromatism – complete lack of hue sensitivity Dichromatism – sensitivity to two primary hues Anomalous Trichromatism – sensitivity to all three hues, with abnormality in retinal cones affecting one of primary pigments Dentists should have their color vision evaluated. If any deficiency is detected, a dentist should seek assistance when selecting tooth shades.
42 : Color blindness test Reverse color blind test
43 : Review of literature
44 :
45 :
46 :
47 : Conventional shade selection
48 : Shade Selection Subjective evaluation with considerable variation Subtle variations can exist without causing disharmony in smile Restoration contour Value of restoration Process improved by applying principles of light and color
49 : Principles of Shade Selection Teeth to be matched must be clean Remove bright colors from field of view - makeup / tinted eye glasses - bright gloves - neutral operatory walls View patient at eye level Evaluate shade under multiple light sources Make shade comparisons at beginning of appointment Shade comparisons should be made quickly to avoid eye fatigue
50 :
51 : Commercial Shade Guides Most convenient and common method of making shade selections Guides consist of shade tabs Metal backing Opaque porcelain Neck, body, and incisal color Select tab with the most natural intraoral appearance
52 : Commercial Shade Guides Vita Classic Vitapan 3D –Master Extended Range Shade Guides
53 : Vita Classic Shade Guide Very popular shade guide Tabs of similar hue are clustered into letter groups A (red-yellow) B (yellow) C (grey) D (red-yellow-gray) Chroma is designated with numerical values A3 = hue of red-yellow, chroma of 3
54 : Red/Yellow Yellow Grey Grey Red/Yellow
55 : Vita Classic Shade Guide Manufacturer recommended sequence for shade matching Hue Selection Chroma Selection Value Selection Final Check / Revision
56 : Vita Classic – Step 1 (Hue Selection) Four categories representing hue A, yellow-red B, yellow C, gray D, red-yellow-gray Operator should select hue closest to that of natural tooth Use area of tooth highest in chroma for hue selection Difficult to select hue for teeth low in chroma
57 : Vita Classic – Step 2 (Chroma Selection) Hue selection has been made (B) Chroma is selected from gradations within the B tabs B1, B2, B3, B4 Several comparisons should be made Avoid retinal fatigue Rest eyes between comparisons (blue-gray)
58 : Vita Classic – Step 3 (Value Selection) Use of second, value ordered shade guide is recommended Value oriented shade guide B1, A1, B2, D2, A2, C1, C2, D4, A3, D3, B3, A3.5, B4, C3, A4, C4, Value best determined by squinting with comparisons made at arms length Decreases light Diminishes cone sensitivity, increases rod sensitivity Tooth fading first has a lower value
59 : Vita Classic – Step 4 (Final Check / Revision) Potential Problem Following value selection, tabs selected for hue and chroma may not coincide with shade tab selected for value
60 : Vita Classic – Step 4 (Final Check / Revision) Possible Findings / Solutions Value of shade tab < natural teeth Select new shade tab with higher value Cannot increase value of restoration with extrinsic staining Will only increase opacity, light transmisison Value of shade tab > natural teeth Select new shade tab with lower value (or) Bridge difference with intrinsic or extrinsic staining
61 : VITAPAN 3D-MASTER Shade Guide
62 : Vita-3D – Step 1 Determine the lightness level (value) Hold shade guide to patient’s mouth at arms length Start with darkest group moving right to left Select Value group 1, 2, 3, 4, or 5
63 : Vita-3D – Step 2 Select the chroma From your selected Value group, remove the middle tab (M) and spread the samples out like a fan Select one of the three shade samples to determine chroma
64 : Vita-3D – Step 3 Determine the hue Check whether the natural tooth is more yellowish or more reddish than the shade sample selected
65 : Vita-3D – Step 4 For more precise shade, intermediate levels for hue, value, and chroma can be given 2.5M2 = value between 2M2 and 3m2 3M1.5 = chroma between 3M1 and 3M2 3M2 / 3L2.5 = hue between 3M2 and 3L2.5
66 : Vita-3D – Value Modification For more precise shade, intermediate levels for value, chroma, and hue can be given 2.5M2 = value between 2M2 and 3M2
67 : Vita-3D – Chroma Modification For more precise shade, intermediate levels for value, chroma and hue can be given 3M1.5 = chroma between 3M1 and 3M2
68 : Vita-3D – Hue Modification For more precise shade, intermediate levels for value, chroma and hue can be given 3M2 / 3L2.5 = hue between 3M2 and 3L2.5 2.5
69 : Extended Range Shade Guides Most shade guides do not cover all the colors in the natural dentition Some porcelain systems extend the typical range Bleached shades Dentin shades Custom shade guides
70 : Shade Mapping Recommended even when good custom shade match exists Tooth is divided into Three regions Nine segments Each region is matched independently Further characterizations are sketched on diagram, may include… Craze lines Hypocalcifications Proximal discolorations Translucency
71 : OTHER POPULAR SHADE GUIDES
72 : Resin Shade Guides
73 :
74 : Special consideration for Direct Composite
75 : Though many condition in esthetic dentistry means ceremaics, composite materials are gaining favors Excellent esthetic potential. Minimal invasive tooth preparations. Acceptable longevity. Relative low costing. Modern fabrication of composite restoration is based on natural layering concept. Dietschi et al. This concept embraces the concept of optical phenomenon and anatomical characteristic of tooth.
76 : For this concept dentin material should be Single opacity. Singel hue. Large chroma scale. Fluorescence. For enamel replacement material are classified. Young enamel – white tint, high opalescence, lower translucency. Adult enamel – neutral tint, less opalescence, intermediate translucency. Aged enamel – yellow or grayish tint, higher translucency.
77 : Basic Layering Concept – Includes one or two set of shaded materials ( with different opacities but same range chroma). For the main restoration volume, completed by limited number of incisal or transparent materials Example – prodigy [ Kerr].
78 : Classic layering concept One basic set of dentin shade [ appox. Same opacity & chroma ]. Two layers of enamel replacement materials, including shaded enamel and incisal materials. Example – Herculite, [ Kerr].
79 : Modern layering concept Use two different shades of dentin replacement . [ different opacity] . Enamel is replace by series of enamel shades.
80 : Trendy layering concept Most recent & promising concept in today’s dentistry. Two basic dentin shades & enamel shades that closely replicate the optical properties of natural tissue and allows for the effect materials between them to create natural look.
81 :
82 : Shade selection protocol
83 : Cleaning of teeth with prophylaxis paste. Selection of dentinal chroma in cervical area. Selection of enamel tint and translucency. Combination of both samples to demonstrate the final restorative effect.
84 : Technology base shade matching
85 : Several clinical studies confirm that computer-assisted shade analysis is more accurate and more consistent compared to human shade selection. [ Paul et al, in 2002] Ishikawa-Nagai et al, reported 80% patients can notice the difference in the shade of their natural teeth compared with their restoration. Advantages No influence on surrounding. No influence on lightning. Results are reproducible.
86 : Measurement systems Spot measurement devices- Measurement of small area of tooth surface. Diameter of optical aperture device – 3 mm. They can use adjunct tool for shade selection. Examples – Shofu ShadeEye-NCC, Chroma Meter system, Vita Easy shade system. Drawbacks – The normal tooth structure is non homogenous so operater get different reference point from tooth which will misguide in comprehensive shade selection.
87 : Complete – tooth measurement devices They measure the entire tooth. Provide a topographical color map of tooth in a one image. Advantages – more consistent, reliable, reproduduciable. Example – X-rite shade vision.
88 : Types of technological shade system RGB devices Require red, green and blue image information to create color image. Most basic approach. Lack of measurement and accuracy. Use for lab technician for reference data. Not solely relies on this devices. Example – ShadeScan system.
89 : Spectrophotometer Measures and records the amount of visible radiant energy reflected or transmitted by an object one wavelenght at a time for each value, chroma and hue present in the entire visible spectrum. This device exposed various light from different angels and directions. Its gives most accurate and precise spectral analysis. There are two different light setting is use in reflectent spectrophotometer instrument : Illumination 0º and observation at 45º ( 0/45). Illumination at 45º and observation at 0º ( 45/0). Example – SpectroShade from MHT.
90 : SpectroShade MHT
91 : Colorimeter These devices engineered to directly measure color as perceived by human eye. Filter the light in three and four areas of the visible spectrum to determine the color of an object. Provide greater data efficiency due to, stroage of three data point of hue, value and chroma instead of 16 or more data points of reflectance recorded by a spectrophotometer. simple, consistently reliable, significantly accurate compared with traditional techniques. Example – ShadeVision.
92 :
93 : Shade vision [ X-Rite] Measurement – complete tooth. Principle – colorimeter. Portable, pc software, visual try-in. Advantages – cordless, good image quality, auto shade correction, access not limited to anteriors teeth. Disadvantages – only 8 image can be capture before downloading can be started, lcd screen is black and white, difficulty in mandibular teeth and sever malaligned teeth. Cost - $ 5500 approx.
94 : Shade Scan ( Cynovad) Measurement – complete tooth. Principle – RGB digital camera. Non portable, pc software. Advantage – good software, enhance image option, organized print report, restoration shade verification. Disadvantages – plastic lens can easily distorted, can distorted images, difficult image capture in sever malaligned teeth. Cost - $ 3500 approx.
95 : SpectroShade ( MHT optic research) Measurement – complete tooth. Principle – spectrophotometer. Non portable, pc image, pc software. Advantages – high accuracy, unlimited no. of image capture, can assess bleaching change, shade varyfication. Disadvantages – expensive, large & bulky, large head can discomfort patients, difficult for malaligned teeth. Cost - $ 10,000.
96 : ikam ( DCM, leeds UK) Measurement – complete tooth. Principle – RGB digital camera. Non portable, having pc image, pc software. advantages - works with digital camera, good image quality. Disadvantages – difficult to position in patients, bulky.
97 : ShadeEye NCC ( shofu ) Measurement - spot. Principle – colorimeter. Portable, no pc image, having pc software, no visual try-in. Advantages – no pc required, direct printout, easy handling, comfortable to patient. Disadvantages – no overall information, insical measurement is poor, work best with shofu ceramics. Price - $ 5500 approx.
98 : Digital Shade Guide ( Rieth, Germany) Measurement – spot. Principle – colorimeter. Non portable, no pc image, having pc software, no visual try-in. Advantages – small devices, good price. Disadvantages – design is not ergonomic, pc-dependent, no strelization.
99 : Easyshade ( Vita, Germany) Measurement – spot. Principle – spectrophotometer. Non portable, no pc image, optional pc software, no visual try-in. Advantages – ease handling, comfortable for patient, access in molar region, tooth and ceramic mode. Disadvantages – works with only vita shades. Price - $ 3000.
100 : Seven steps to a successful Shade selection
101 : Preoperative patient evaluation Are there any contrast effect present that may affect color perception? How restoration affect the overall smile? Is there any significant variation in the shade of the gingival, body, and incisal section of the teeth? Can patient teeth categorized as high translucency/ high opacity? Will material selection significantly affect the final esthetic outcome of the restoration?
102 : Analysis Use all the tool available for shade selection. First, technology should be used to determine both an overall basic shade as well as shade of each section of teeth. [ gingival, body, and incisal]. Then shade tabs is use to confirm the data.
103 : Communication Clinician should take reference photographs of shade tabs suggested by digital analysis, extreme shade tabs next to the dentition to be matched. Full smile showing the surrounding dentition. Photos should be taken in different angulations and different lightning conditions. Now once this all information is gathered send all this information to lab technician.
104 : Interpretation Laboratory must interpret all of the shade information. Reference photographs help the technician shade tab selection. Digital color map of tooth gives detail shade of the tooth. Now technician, translate this data in the from of ceremic language.
105 : Fabrication
106 : Varification Final placement
107 : Conclusion World is emphasis on an esthetic standered probabaly responsible for driving the most recent advances in shade matching. Along with shade matching tooth size and proportion,symmetry,outline from
108 : References Esthetic color training in dentistry – Rade D. Paravina. Esthetic dentisry and ceramic restoration – Bernard Touati. Fundamental of color – Chu, Devigus. Contemporary fixed prosthodontics – Rosentstiel Fixed prosthodontics – dental clinics of north america July 2004. Pubmed. World wide web.
109 : Thank You

 

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