This presentation covers in detail all the information necessary for a dentist to understand the importance of colour in dentistry, and how its use adds to one's knowledge in dental esthetics.

1. Colour is a human need like fire and water.
It is a raw material indispensable to life
- Fernand Leger
(artist)
The science and art of porcelain laminate veneers - Galip Gurel 1

2. Understanding
Colour
Presented by:
Apurva Thampi
MDS 1st year
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3. Contents
• Introduction
• Types of colour
• Colour perception
• Factors influencing colour perception
• Dimensions of colour
• Colour measurement
• Contrast effect
• Impact of materials and material science on colour
• Shade selection
• Systems for shade selection
• Steps in shade selection
• Advances in shade selection
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4. Introduction
• Clinician masters the art and science of colour treatment planning
• Clinician has correctly communicated the shade selections to the
laboratory
• Correct interpretation by the laboratory technician
For a successful esthetically pleasing anterior restoration
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5. Terminologies
• Translucency : It is the amount of incident light transmitted and
scattered by the object
• Opacity: It is the opposite of translucency. It is the ability of a material
to block the passage of light
MATERIAL WITH HIGH OPACITY IS THE MATERIAL WITH LOW
TRANSLUCENCY
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6. • Opalescence : Optical property of the material in which there
is a scattering of the shorter wavelength of the visible
spectrum.
• Iridescence : it is the rainbow like effect of different colours which
changes according to the angle from which they are
viewed or the incidence angle of the light source
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7. • Fluorescence : Absorption of light by a material and the spontaneous
emission of light in a longer wavelength.
• Luminiscence : Any process in which energy is emitted from a
material at a different wavelength from that at which it
is absorbed
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8. • Phosphorescence: Light emitted by an atom or molecule persists after
the excitation source is removed. It is temperature
dependent
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9. Types of colour
Spectral colours
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10. Types of colour
Pigment colours
Primary colour Secondary colour Complementary colour
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11. Colour perception
• Absorption and reflection of various wavelengths of light
• Psychophysical reality of colour
The science and art of porcelain laminate veneers - Galip Gurel
Colour Perception Psychophysiological
reality
Physical Wavelength of light
Psychophysical Reception of wavelength
of light by the eye
Psychological Interpretation of
wavelength of light by
the brain
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12. Factors influencing colour perception
Illuminant
ObserverObject
• Colour content
• Colour rendering effect
• Reflection
• Transmission
• Individual differences
• Binocular differences
• Age
• Drugs
• Fatigue
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13. Color content:
Intensity of light emitted at each
wavelength which varies according to
the type of illuminnat
Colour rendering:
It is the effect that the illuminnt has
on the colour appearance under a
reference source
Colour rendering index:
Measue of the degree to which the
illluminnat can impart colour of an
object compared with that acheieved
by a reference source
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14. Reflection:
A material gains it reflective
colour by reflecting the part of
the spectrum of light incident
upon it and absorbing the other
parts of the spectrum
Transmission:
A translucent material gains its
transmitted colour by the
spectrum it transmits.
Wavelengths that are not
transmitted are absorbed
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15. • Individual differences in colour
Number of Dentist Number of prosthesis Number of natural teeth total
Same shade selected by 3
dentists
18 teeth (14%) 10 teeth (14.3%) 28 teeth (14%)
Same shade selected by
two dentists
72 teeth (59.2%) 30 teeth (42.9%) 102 teeth (51.5%)
Same shade selected by 0
dentists
38 teeth (26.7%) 30 teeth (42.9%) 68 teeth (34.3%)
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16. • Chronological age and colour perception
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17. • Fatigue and colour perception
• Adverse visual perception – due to systemic/local/mental fatigue
• Drugs and colour perception
Drug Effect
Alcohol/Morphine Long wavelength = brighter
Short wavelength = darker
Caffeine Long wavelength = darker
Short wavelength - brighter
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18. It is the
phenomenon
where an object
appears
different in
different lighting
Tooth under
corrected
lighting
Tooth under
fluorescent
lighting
Tooth under
incandescent
lighting
M
E
T
A
M
E
R
I
S
M
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19. Dimensions of colour
Hue
Value
Chroma
Translucency
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20. Munsells
colour system
CIE colour
system
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21. Attribute of
colour that
makes it
appear blue,
yellow or red
Lightness or
darkness of
colour
Intensity of
colour or
amount of
hue saturation
(runs from 0-
10)
HUE CHROMAVALUE
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22. • Developed by Commision
International de
l’Eclairage
• Based on the concept of
TRICHROMACY
• Three primaries –
tristimulus values
• 1931 – concept of
standard observer was
introduced
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23. • Terminologies used in CIE colour system
• Imaginary primary colours – [X],
[Y], [Z]Primaries
• In 1964 – a 2º viewing angle
• Characterise response of cone
receptors denoted as x,y and z
• Perception of colour depends on,
light, object, observerTristimulus values
• Decribes the other two dimensions
of colour
Standard observer
Chromaticity
Color matching
function
Chromaticity diagram
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24. In CIE L*a*b
• L represents lightness or value
• ‘a’ is the measurement along red-green axis
• ‘b’ is the measurement along yellow -blue axis
Colour difference ΔE* = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2
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25. Colour measurements
Spectrophotometers
It measures the amount of light
reflected at each wavelength
Double beam
spectrophotometer
Compares responses with a
reference standard
Colorimeters
It measure the amount of light
reflected at selected colours are
based on the CIE tristimulus
Disadvantages:
EDGE EFFECT
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26. • Photography + spectrophotometry
Clinician holds 3-4 most matching shade guides
Photographed under 35mm camera under balanced light
Sent to dental laboratory
A computer program aids in selecting the closest match
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27. Contrast effects
Optical
illusions
Simultaneous
contrast
Light/Dark
contrast
Hue contrast
Successive
contrast
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29. Light/ Dark contrast Hue contrast
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32. Areal contrast
Visual colour perception affected by the size of the object
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33. Spatial contrast
Spatial contrast is equated to brightness and size
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34. • One colour is observed after the perception of another colour
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35. Impact of materials and material science on colour
• McLean from England – innovators in dental ceramics
• Improved characteristics – higher density
• Increased density – better light transmission
• Five categories of materials used in tooth coloured restorations
• Sintered Aluminium oxide ceramics (Procera)
• Lithium disilicate ceramics (IPS Empress 2 Eris)
• Leucite reinforced ceramics (Empress I, Cerpress SL)
• Feldspathic ceramics (Creation, Ceramco 3, Finesse)
• Synthetic low fusing quartz glass ceramics (HeraCeram)
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36. • Full coverage – excellent marginal adaptation
• High resistance to fracture (690 Mpa)
• High opacity
• Low translucency
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37. • Developed in 1998 (IPS Empress 2)
• Fracture toughness – 340 Mpa
• Excellent marginal adaptation and superior marginal integrity
• More opaque than conventional materials
• Esthetically beneficial for masking discoloured teeth
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38. • Developed by Ivoclar in 1990
• Fracture toughness – 180MPa
• Can be fabricated with varying forms of opacity – high, medium and
translucent
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39. • Weinstein in 1960 – metal ceramic restorations
• Highly versatile
• Can be produced using platinum foil or refractory die technique
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40. • Karino in 1982 – metal ceramic restoration
• McLaren in 1998 – fired at 100ºC lower than feldspathic ceramic
• Chu in 2001 – completely synthetic glass ceramic for metal ceramic
restorations
• Causes less wear to the opposing natural tooth
• Low opacity
• High translucency
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41. To be continued…
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42. Welcome back!!!
42

43. Shade matching
Shade matching is a process of
converting shade perception into
shade communication
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44. Importance of shade matching in dentistry
Natural appearance
of the teeth
Proper
communication with
the dental laboratory
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45. Shade guide systems
Conventional shade guide
systems
Technology based shade
guide systems
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Gurel
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46. Conventional shade guide systems
• Used as visual guides
• Require a neutral environment
• Maintenance of quantity and quality of light
• Absence of eye fatigue
• Examples : Vitapan Classical, Ivoclar Chromascope, Vitapan ED
Shademaster
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Gurel
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47. Vitapan Classical shade
guide
• Based on hue
• Categorised into groups
• A – Orange
• B – Yellow
• C – yellow/gray
• D – Orange/gray
(brown)
Chromascope system
• Based on hue
• Uses numbers instead of
letters
• 100 – white
• 200 – yellow
• 300 – orange
• 400 – gray
• 500 - brown
Vitapan 3D shademaster
• Based on value
• Different from
conventional systems
• L – tendency
towards yellow hue
• R – tendency
towards red hue
• Developed by Miller and
further by McLaren
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48. Sequence for shade selection
Basic shade
Basic shade variations
Enamel shade,
translucency and location
Special effects
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49. Armamentarium for shade selection
Shade guide
Shade prescription form
Accesory shade guides
Instant photograph or slide
Daylight colour corrected fluorescent lighting
Neutral environment
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50. • Accessory armamentarium include:
• Magnifying loops
• Fluid resin stains
• Custom shade tabs
• Hand mirror
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51. Basic shade
• Match centre shade of natural tooth with closest appropriate tab
• Hue should be assessed correctly
• Tabs with same colour may appear similar
• Doubts?? - compare two approximate matching tabs under the
natural tooth
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52. • A shade – young individuals
• B shade – rarely encountered in natural dentition
• C shade– middle aged / older individuals - subgroup of B ( similar hue
but lower value)
• D shade– subgroup of A
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53. Basic shade variations
ORANGE MODIFICATION
• Natural tooth colour - either orange or yellow hue
• Porcelain shade guides are yellow hue not orange
• Orange tonality – confined to cervical aspect of the tooth
• Apply fluid colour resin – helps visualize quality or intensity of tone
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54. VARIATIONS BASED ON LOCATION
• Most frequent variation observed at the incisal third
• Next frequent was uniform – monochromatic appearance
• Thirdly, colour deviation from basic hue – cervical third
• Cervical variations – cervical part of the shade tabs
• Basic hue of the incisal third – mammelon colour
• Mammelon – blunt and widen with aging – whitish orange hue
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55. Laboratory considerations
• Basic hue – dentin build-up
• Single shade or different hues alternated horizontally
• Opal/vintage porcelain system – bright shades of high value –
preserve value through firing cycles
• Mix 10% corresponding value plus porcelain with dentin shade
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56. • Additional brightness – mix 20 – 30% of value plus porcelain
• Shades with low value – value plus porcelain - separate opaque layer
• Modified dentin shades – cervical dentin, mammelon dentin, orange
modified dentine, secondary brown/orange dentine
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57. Enamel shade and translucency
• Quality and location of enamel overlay
• Young individual – whiter teeth, middle aged – orange teeth
(translucent or almost transparent enamel)
• Evaluation done in 2 ways
• Patient holds the tab below the tooth while the clinicians stands back 2 yards
• Patients holds the tab below the tooth and stands facing a mirror whielt the
clinicians makes the evaluation from behind
• Natural tooth has higher value – low chroma/high value dentine +
opaque reflective dentine is used
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58. Laboratory considerations
• Young tooth – bright reflective enamel
• Increased translucency – enamel mixed translucent or transparent
powder
• Maintain same degree of opacity – overlaid over enamel
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59. Need for improved systems for shade selection
Selection subject to variability
Shade selection protocol has several difficulties
Metamerism
Improved ceramics – changes in light reflection, absorption,
refraction and dispersion
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60. Technology based shade guide systems
1998 –
Shofu
SadeEye –
Ex Chroma
Meter
1999 – Vita
Easy shade
2000 – Shade
scan
2000 –
ShadeRite
Dental Vision
system
2001 –
SpectroShade
System
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61. Shofu ShadeEye – Ex Chroma meter
• First reported by Goldstien
• Freestanding hand held probe – 3mm
• Placed against tooth – activated
• Flash of light through probe
• Reflected light transmitted through centre of probe
• Evenly distributed through colour filters
• Docking unit via infrared signal
• Database of porcelain samples
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62. VitaEasy Shade system
• Hand held spectrophotometer
• Connected to based by mono-coil fibre optic cable assembly
• Contact probe tip – 5mm
• 19 - 1mm diameter fibre optic bundles
• Tooth illuminated by a halogen bulb
• Spectrometers measure the internally scattered light
• Spectral reflectance is measured in 25 nm bandwidth
• Displays closest vita shade in classical/3D guide system
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63. ShadeScan system
• Hand held probe + LCD screen
• Fibre optic cable – halogen light – incident on tooth surface at 45
degrees
• Light intensity continuously monitored
• Image recorded on a flash card
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64. ShadeRite Dental Vision system
• Hand held + LCD screen
• Glare spot for focus and alignment
• Focused on junction of gingival and middle thirds
• Measurement through series of rotating filters
• Shade and translucency mapping possible and
downloaded
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66. SpectroShade system
• Most complex
• Most flexibility – data
• Digital color imaging with spectrophotometric analysis
• Large hand piece
• 2 step process
• Postioned against green and white background
• Light halogen tube on tooth – 45 degrees
• Image is seen on computer screen
• Incident light monochromated
• Spectral scanning – 10nm bandwidth
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68. Clear match system
• Purely software based
• Requires a Windows PC and digital camera
• Black white standards and shade tabs need to be included in each
photo
• Detailed shade mapping is possible
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69. Conventional V/S technology based systems -
Advantages
Conventional
• Cost effective
• Easy to use
• Visual tool
• transportable
Technology based
• More objective
• Verification of restoration shade
in the lab
• Not influenced by surrounding
environment
• Increased producvtivity
• Tooth dehydration not an issue
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70. Conventional V/S technology based systems -
Disadvantages
Conventional
• Subjective
• Inconsistency in manufacturing
• Easily affected by surrounding
environment
Technology - based
• Increased cost
• Interpretation of the report is
technician dependent
• Not easy transportable
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71. Conclusion
Understanding colour requires learning the language of colour. In order
to overcome the challenges associated with shade selection in esthetic
dentistry, it is essential to learn the art and science of colour. Close co-
operation of the clinician and the laboratory technician is also required.
Only then can an ultimately esthetic restoration be achieved
“A beautiful smile is no longer considered a luxury but rather as an
essential component or current lifestyle”
- Stephen J Chu
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72. Bibliography
• Science and art of porcelain laminate veneers – Galip Gurel
• Esthetics of anterior fixed prodthodontics – Gerard J. Chiche, Alain
Pinault
• Advances in color matching,Jane D. Brewer, DDS, MSa,*, Alvin Wee,
BDS, MSb,c,Robert Seghi, DDS, MSb : Dent Clin N Am 48 (2004) 341–
358
• Clinical Steps to Predictable Color Management in Aesthetic
Restorative Dentistry Stephen J. Chu, DMD, MSD, CDT : Dent Clin N
Am 51 (2007) 473–485
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73. • Colour in relation to dentistry. Fundamentals of colour science S M
Burkinshaw : British Dental Journal 196, 33 - 41 (2004)
• Color matching in dentistry. Part I The three-dimensional nature of
color : Robert C. Sproull, D.D.S. : JPD vol 29(4) 416
• Color matching in dentistry. Part II : Practical applications of the
organization of color : Robert C. Sproull, D.D.S. : JPD vol 29(5) 556
• Color matching in dentistry. Part III : colour control : Robert C. Sproull,
D.D.S. : JPD vol 31(2) 146
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74. THANK YOU
AND
HAVE A PLEASANT
DAY!!!
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