Study on how to choose tooth shade/colour. Comparison on using the manual technique and modern digital technique.

1. VISUAL VERSUS SPECTROPHOTOMETRIC ANALYSIS OF TOOTH SHADES
IN VITAL HUMAN TEETH
Mick Iván de Sousa Muianga (MScDent)
Mick Iván de Sousa Muianga (MScDent)
University of the Witwatersrand
School of Oral Health Sciences
Department of Prosthodontics
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2. INTRODUCTION
In order to achieve optimum results when replacing natural teeth a number of factors such
as size, angle, shape, colour, cusps, proportionality, alignment, age, smile line, contact
surfaces, surface texture etc are some aspects that are important in accomplishing
optimum results.
Of the above mentioned factors colour is amongst the most demanding with patient
satisfaction. Presently in the there are various visual and computerized shade guides
which are used to determine natural shade of teeth. The visual guides have come under
much scrutiny in their accuracy, with the ever developing computerized systems, research
has shown that these fair better than their visual counter parts as reported by Paul et al
(2002). A finding by the latter researchers showed that the less the accurate the system
the higher the degree of reproducibility, this is probably due to the limited number of
shades available in these systems. Determination of tooth color by visual means is
considered highly subjective. General variables such as external light conditions,
experience, age, fatigue of the human eye and physiological variables such as color
blindness lead to inconsistencies Wyszeck and Stiles (1982); Hunter and Harold (1987);
Berns (2000).
Tooth colour is defined in 3 terms; Hue - the tint, or the blend of red, blue and green that
make up the colour. Chroma - the saturation of the colour. For example, chroma is what
makes a colour photograph different from a black and white photograph. Value - the
brilliance or brightness of a colour (the amount of grey). It should be noted that young
teeth are bright and opaque with low chroma Baratieri et al (1998). With aging, chroma
increases while hue remains essentially the same, taking on a slight red tint. The teeth
also become more transparent with age, thus reducing the value Ritsco (1998).
In the present society of cosmetic demand many dentists have had little or no training in
vision physiology or color science and therefore large inaccuracies have been reported
YPD.
With the increase in number of shade guides and all manufacturers claiming their product
to the best, the following study compares which shade guides were more accurate and if
in fact the “standard shades” were factual in all visual shade guides and computerized
shade guides.
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3. METHOD
5 shade guides were compared; 3 Visual and 2 Digital:
●Vita 3D Master
●Vitapan Classical (Lumin-Vaccum)
●Ivoclair Vivadent Chromascop
●DeguDent Shadepilot Type 71.3000
●SpectroShade Micro Type 71.3000
Vitapan 3D-Master
DeguDent Shadepilot
Type: 71.3000
Ivoclair Chromascop
Vitapan Classical Lumin-Vaccum
Spectro Shade Micro
Type: 71.3000
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4. -A total of 10 participants were asked to take part in the study.
-Participants were chosen at random regardless of age, race etc.
-The study was done over 1 day from 08:30-12:00.
-A dental ceramist was present at all times to evaluate the study process.
-A detailed explanation of all processes were explained clearly to participants.
-Only natural vital teeth were chosen for analysis.
Procedure
1. A white drape covered the clothes of the participants.
2. Lipstick and bright make up was removed.
3. Participant‟s mouth was at operator‟s eye level.
4. Shade comparisons were performed at five-second intervals to avoid eye fatigue.
5. A colour adjusted light source was used.
6. Visual methods from the anticipated least accurate to most accurate
methodological order, the computerized systems were last to avoid influence from
the computerized systems results.
7. When unable to precisely match the shade, lower chroma and higher value were
chosen for the closest shades.
5 shade guides were used:
1. Vitapan Classical Lumin-Vaccum
2. Ivoclair Chromascop
3. Vita 3D-Master
4. DeguDent Shadepilot Type 71.3000
5. SpectroShade Micro Type 71.3000
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5. RESULTS
№ Age Sex Tooth Time
Method
Vitapan Classic
Lumin-Vaccum
1
2
3
4
5
6
7
8
9
10
25
47
69
71
39
28
22
21
30
62
M
M
M
F
F
F
M
F
F
F
11
11
11
21
21
21
11
21
21
21
08:35
08:45
09:15
09:30
09:50
10:05
10:30
11:20
11:40
12:00
Ivaclair
Cromascop
Vita
3D-Master
DeguDent
Shadepilot
71.3000
SpectroShade
Micro
71.3000
D3
C2
A4
D4
A2
A3
B2
C2
B4
B3
2B
6D
4D
2E
4B
1E
1A
6B
2C
1E
2M2
4M2
5M1
4M2
3R1.5
2M2
2M2.5
3L1.5
3M
2M2
D3
C4
C4
D3
A2
A1
B2
D2
B3
A2
3M2
4R2.5
4M2
4R1.5
2M2
1M1
2R1.5
3L1.5
3R
2M2
Table 1. Results of Colour shades by 5 different methods on vital teeth of 10 Patients
DISCUSSION
The SpectroShade Micro had the Vitapan Classical, Vitapan Classical Lumi-Vaccum,
Ivoclair Chromascop amd Vita 3D-Master software installed, the DeguDent Shadepilot
only had the Vitapan Classical software installed.
There were some marked differences between the visual guides and the computerized
guides as well as between the visual systems.
The Vitapan only has 16 shades which totally limit shade selection thus proving to be
extremely inaccurate in addition its cluttered sorting makes shade selection confusing.
Vita Classic shade tabs are not systematically distributed in the color space relevant for
human teeth, and that there is even overlapping Miller (1987).
Ivoclair Chromascop with 20 shades faired better, the chromatic arrangement and the
ability to remove each group and each shade tab was of great value in accuracy, the
limited shades available however diminished its accuracy level.
Vita 3D-Master although more complex has a wider range of shade values of 26 which
are arranged into value, chroma and hue. By first selecting the tooth‟s „value‟, followed
by its „chroma‟, and then its „hue‟ the closest to exact can be achieved, in addition by
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6. being able to separate the cervical, middle and incisive areas of the selected tooth, close
to accurate shades can be attained ViDent. 3D-Master shade System. Dental Technology
Update. 2006; 1:1-3. It is however a time consuming system.
The external factors are a major dilemma on all visual guides.
The DeguDent Shadepilot was much easier to use, the only draw back was the limited use
of software, thus immediate comparisons with the different systems were unable to be
conducted on the same machine.
The SpectroShade Micro needed an extremely steady hand, but results when the scan was
taken correctly were extremely positive and in almost all cases the two digital shade
guides showed equal results.
Visual Shade Guides
Advantages
1. Uncomplicated to use
2. Inexpensive
3. Disinfection possible
Disadvantages
1. Non-standardized shades i.e. different shades with different companies
2. Denaturing of shades with time
3. Degree of light absorption and reflection different on each different manufacturer
4. Light source dependent on environment
5. Guides lack metal tabs for PFM
6. Degree of translucency unable to accurately match natural teeth
7. Incorrect technique of operator/ insufficient colour training leads to inaccurate
results
8. Low degree of reproducibility
9. Incomplete or errors in information between the dentist and technician
10. Time consuming in trying to achieve accurate shades
11. Shade tabs are condensed differently than porcelain used for final restorations.
12. Shade guides are not always made with fluorescent porcelain, which causes
inconsistencies in color matching.
13. High degree of training and visual acuity required to achieve reasonable to
accurate results.
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7. Spectrophotometric Shade Guides
Advantages
1. High degree of reproducibility
2. Precise differences of shades
3. Constant light source
4. Shade definition per ⅓ of tooth, translucency, colour definition, shade comparison
features available thus providing relatively high accuracy of shade in cases where
the technician may use a different system to the dentist
5. Disinfection possible
6. The dental technician has the exact evaluation as the dentist since the results are
stored in the digital shade guide
7. The null hypothesis the spectrophotometers use revealed a very good match with
visual shade determination of the body color of natural teeth.
8. The three-dimensional information is translated into a two-dimensional map of
light intensities. The closest match of the readings from a tooth with the data of
the color library results in the shade chosen by the spectrophotometer
Disadvantages
1. Sophisticated equipment required
2. Expensive to purchase and maintain
3. Functionally complex dependent on battery life to sustain continued use.
Common disadvantages with all shade guides which lead to incorrect results:
1. Porcelains do not match the shade guides that they are being compared to.
2. Shade variations occur between different die lots of porcelain from the same
manufacturer.
3. Shade guide tabs are 4-5 mm thick compared to the thin 1.5-2.00 mm layers of
porcelain used for the restoration.
4. It is difficult to predict the final shade after the layering of opaque, dentin and
enamel.
5. A vital tooth is both naturally translucent and transparent. Porcelain is a
heterogeneous material
6. The shades available by manufacturers is still insufficient compared to those
appearing in natural teeth YPD
http://www.healthmantra.com/ypd/jan2002/shade%20selectionhtm
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8. CONCLUSION
The spectrophotometric systems showed more accurate results with greater
reproducibility, due to external factors (such as operator, skill, ambient light, angle etc)
the visual systems varied in results.
The use of the 5 guides system should be repeated with only 3-5 participants and 10-15
investigators to show the degree of reproducibility thus achieving greater accuracy for the
same study. To compare reproducibility between computerized systems at least 5
different digital guides with all available software installed should be used, the number of
participants should also increase substantially.
Further clinical study is required to evaluate if spectrophotometric analysis can be used to
replace or used in conjunction with the human eye for determination of tooth shades.
REFERENCES
Baratieri L et al. Esthetics: Direct Adhesive restoration on Fractured Anterior Teeth.
Quint Books. 1998; 48-50.
Berns RF. Billmeyer and Saltzman‟s principles of color technology. New York: Wiley.
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Hugo B, Witzel T, Klaiber B. Comparison of in vivo visual and computer-aided tooth
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Hunter RS, Harold RW. The measurement of appearance. New York: Wiley. 1987; 3-68.
Klemetti E, Matela A, Haag P and Kononen M. Shade selection performed by novice
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Miller L. Organizing color in dentistry. J Am Dent Assoc (Spec Iss). 1987:26E–40E.
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Ritsco R. Determining restorative shade using the Chromascop universal shade guide by
Ivoclair North America, Inc. Dental Lab Products Artcle; 1998.
ViDent. 3D-Master shade System. Dental Technology Update. 2006; 1:1-3.
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formulae. New York: Wiley. 1982;2:83-116.
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