Visual and Digital Shade Analysis of Vital Human Teeth


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Study on how to choose tooth shade/colour.

Comparison on using the manual technique and modern digital technique.

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Visual and Digital Shade Analysis of Vital Human Teeth

  1. 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 1
  2. 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. 2
  3. 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 3
  4. 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 4
  5. 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 5
  6. 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. 6
  7. 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 7
  8. 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. 2000;3:75-104. Hugo B, Witzel T, Klaiber B. Comparison of in vivo visual and computer-aided tooth shade determination. Clin Oral Investig. 2005; 9(4):244-50. 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 dental professionals and colorimeter. J of Oral Rehab. 2006; 33:31. Miller L. Organizing color in dentistry. J Am Dent Assoc (Spec Iss). 1987:26E–40E. Paul S, Peter A, Pietrobon N, and Hämmerle CHF. Visual and Spectrophotometric Shade Analysis of Human Teeth. J Dent Res. 2002; 81(8):578-582. 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. Wyszecki G, Stiles WS. Color science concepts and methods, quantitative data and formulae. New York: Wiley. 1982;2:83-116. 8