Shade selection

Major challenges in cosmetic dentistry are to accomplish appropriate and satisfactory reproduction of natural shade of teeth.1

The kind of shade guide, individual ability to choose shades and conditions the choice is made under, all have influence on reliability and accuracy of the procedure.

Shade selection in dental practice is an important but difficult task.

Dentists are challenged to satisfy the aesthetic requirement of patients when they select the shades for fabrication of prosthesis. Most dentists are usually not trained for shade selection.2

1. SHADE SELECTION Dr. N akul patidar

2. CONTENT:- INTRODUCTION DEFINATION TRIDIMENSIONAL PROPERTY OF COLOUR PERCEPTION OF COLOUR SHADE SELECTION BASED ON SHADE SELECTION TECNIQUE A) VISUAL - VITASPAN CLASSICAL SHADE - VITASPAN 3D SHADE GUIDE B) INSTRUMENTAL - RGB DEVICE - SPECTROPHOTOMETER - VITA EASY SHADE - SPECTRO SHADE MICRO - SHADE VISION SYSTEM 6. PROCEDURE 7. PROBLEM INHERENT TO MATCHING SHADES OF TEETH 7. CONCLUSION 8. REFERENCES

3. INTRODUCTION Major challenges in cosmetic dentistry are to accomplish appropriate and satisfactory reproduction of natural shade of teeth. 1 The kind of shade guide, individual ability to choose shades and conditions the choice is made under, all have influence on reliability and accuracy of the procedure. Shade selection in dental practice is an important but difficult task. Dentists are challenged to satisfy the aesthetic requirement of patients when they select the shades for fabrication of prosthesis. Most dentists are usually not trained for shade selection.2

4. DEFINATION SHADE SELECTION:- According to the Glossary of Prosthodontic terms “ The determination of the color and other attributes of appearance of an artificial tooth or set of teeth for a given individual ” COLOUR:- According to the Glossary of Prosthodontic terms “The quality of an object or substance with respect to light reflected or transmitted by it.”

5. TRIDIMENSIONAL PROPERTY OF COLOUR In 1900 , American painter Albert Henry munsell wrote about tri-dimensional property of colour MUNSELL COLOUR SYSTEM

6. HUE VAL UE Most important factor in tooth shade matching. CHROMA Dominant colour of object (red, yellow, green ) lncrease toward high end (Lighter) and Decrease toward low end (Darker) Degree of saturation/strength/intensity of the particular hue Short wave length = Violet Hue •Long wave length = Red Hue Vital teeth- High value Non vital teeth- Low value Grey High Chroma = High amount of Hue with little dilution Low Chroma = Small amount of Hue with large amount of dilution Most natural teeth fall in a Hue range between yellow and yellow-red -6YR-9.3YR Most teeth fall in a range from 4-8 Teeth have a Chroma range of 0-7

7. TRANSLUCENCY The gradient between transparent and opaque Increasing the translucency of a crown lowers its value because less light returns to the eye. The translucency of enamel varies with the Angle of incidence Surface texture Wavelength Level of dehydration FLUORESCENCE It is the absorption of shorter wavlength light and the spontaneous emission of light in a longer wavelength In a natural tooth, it primarily occurs in the dentin because of the higher amount of organic material Ambient near- UV light is absorbed and fluoresced back as light primarily in the blue end of the spectrum The more the dentin fluoresces, the lower the chroma

8. OPALESCENCE Opalescence is the phenomena in which a material appears to be of one color when light is reflected from it and of another color when light is transmitted through it. The hydroxyapatite crystals of enamel also act as prisms. When illuminated, Enamel will transilluminate the rods scatter the blues within their body thus, enamel appears bluish even though it is colorless. The opalescent effects of enamel brighten the tooth and give it optical depth and vitality.

9. PERCEPTION OF COLOUR which depends on three entities: 1. Light source (illuminant); 2. Object; and 3. Detector (ocular or instrumental).

10. 1. LIGHT SORCE (ILLUMINANTS) :- COLOUR RENDITION:- The property of light source to influence colour of object Three main illuminants within any dental practice Natural Incandescent – higher concentration of yellow light Fluorescent - higher concentrations of blue light waves Acc to ADA , “color-corrected” fluorescent lighting with a CRI of 90 or above is recommended for shade selection

11. 2. OBJECT Hue is wavelength of light and dependent on the spectral reflectance from an object. Chroma is the concentration of colour or colour intensity of object High value object reflects most the light falling on surface and appears bright. Low value object absorbing most of the light and appears dull. 3. DETECTOR (SENSATION):- The difficulty of shade selection is that clinicians must be able to interpret a multi-layered structure of varying thickness, opacities and optical surface characteristics. The basic hue of the tooth is determined by the colour of the underlying dentine , while value is a quality of the enamel overlay Muia in 1993 stated, “The dentine imparts all the colour. Enamel is like a fiber optic structure conducting light through its rods”

12. SHADE SELECTION BASED ON (ACC TO JOINER AND ALVIN) Physical and Optical properties of tooth being viewed Nature of light to which tooth is exposed Assessment of tooth shade by observer Relationship of tooth to its surrounding colour structure

13. (A) PHYSICAL AND OPTICAL PROPERTIES OF TOOTH BEING VIEWED Most important physical property related to a tooth’s shade is its moisture content Appears whiter and less saturated in dry condition If tooth dry than it will takes almost 20–30 minutes for the tooth color to return to its baseline values To make shade selections at the start of a dental procedure rather than at its end Research by Ten-Bosch and Coops , showed that dentine was responsible for imparting the basic tooth color, which was further modified by its external features On the basis of these normal physiologic phenomena, Wagenaar and Smith have suggested that the shade selection process is directly related to three essential factors: The Tooth being viewed The Light source being used The Eyes of the observer.

14. NATURE OF LIGHT TO WHICH THE TOOTH IS EXPOSED Scientifically, Light is an electromagnetic radiation visible to the human eye, having a wavelength from 380-750nm that lies between the shorter wavelengths of ultraviolet light and longer wavelengths of infrared light. Sunlight remains a major source of energy and its distribution and intensity depends on different factors light during morning or evening hours is rich in yellow and orange but lacking in blue and green For shade selection purposes in the form of “ Northern daylight ” i.e. sunlight around the noon hour on a bright day with slight overcast CRI of close to 100

15. ASSESSMENT OF TOOTH SHADE BY AN OBSERVER Capability of the eyes to decrease when a tooth is viewed for longer than 10 seconds observed color becomes less and less saturated while simultaneously increasing the chroma of complementary colors. It has been recommended by Alvin and Azad et al to paint the operatory walls in pale blue (complimentary to yellow color of teeth) and to resensitize the eyes to yellow color of teeth by focusing on a pale gray-blue surface immediately before and during the shade selection procedure.

16. RELATIONSHIP OF THE TOOTH TO ITS SURROUNDING COLORED STRUCTURES AND SURFACES Tooth color perceived by an observer is influenced by other colored structures surrounding the tooth such as adjacent teeth, gingival, lips, face skin, clothing of the patient and operatory walls. Presence of dark colored lipstick creates the illusion of whiter teeth it is believed that individuals with darker skin colors have lighter shades of teeth, which is explained by the illusion of greater contrast between skin color and tooth shade Clothing worn by the patient and color of operatory walls can create contrast effects during the shade selection process Therefore, it has been recommended to drape all bright colored clothing prior to shade selection while the operatory walls should be painted in a neutral (pale gray-blue) color

17. SHADE SELECTION TECNIQUE 1. VISUAL Quick Cost effective Subjective Color discrimination

18. First shade guide introduced by Vita zahnfabric Vita classical shade 16 shade tab is available Potential Problem following value selection, tabs selected for hue and chroma may not coincide with shade tab selected for value A B C D VITASPAN CLASSICAL SHADE

19. 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

20. 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)

21. 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 and Tooth fading first has a lower value

22. Vita-3D – Step 1 (Value Selection) Determine the lightness level (value) Hold shade guide to patient’s mouth Start with darkest group moving right to left Select Value group 1, 2, 3, 4, or 5 VITASPAN 3D SHADE GUIDE

23. Vita-3D – Step 2 (Chroma Selection) 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

24. Vita-3D – Step 3 (Hue selection) Determine the hue Check whether the natural tooth is more yellowish or more reddish than the shade sample selected For example:- Tooth with 3M2 selected Mean= Value- 3 Hue- M iddle Chroma- 2

25. 2. INSTRUMENT Objective Reproducible Equipment cost Operational difficulties SHADE SELECTION TECNIQUE

26. RED, GREEN, BLUE image information to create a color image. Use for reference point of view RGB devices example- Digital camera,Cynovad ShadeScan™ measures shades over the entire tooth surface, then analyzes them and generate a shade match Shade scan for crown and bridge and for direct restoration RGB DEVICES Additive Subtractive

27. It measures and records the amount of visible radiant energy reflected or transmitted by an object one wavelength at a time for each value, chroma and hue present in the entire visible Spectrum. Crystaleye combines the benefits of a traditional spectrophotometer with digital photography SPECTROPHOTOMETERS Compared with observations by the human eye, or conventional techniques, it was found that spectrophotometers offered a 33% increase in accuracy and a more objective match in 93.3% of cases

28. SPECTROPHOTOMETER PRINCIPLE

29. VITA EASY SHADE Small portable Cordless Battery operated Contact type

30. SPECTRO SHADE MICRO An imaging spectrophotometer It uses a digital camera/LED spectrophotometer combination

31. SHADE VISION SYSTEM An imaging colorimeter. Complete tooth image is provided through the use in the area of gingival, middle and incisal third

32. According to Kuzmanović and Lyons Study found no significant difference in the accuracy of shade selection when using either a conventional visual assessment technique or a colorimetric instrument. Colorimeters are significantly less reliable than spectrophotometers and digital camera Combination of visual color determination (Vitapan 3D‑Master shade guide and Linear guide) with digital cameras and electronic devices (spectrophotometers) increase chances for successful shade matching

33. PROCEDURE

34. DIRECT COMPOSITE PLACEMENT TECHNIQUE Colour mock up created by chromatic and achromatic technique silicone matrix made on a waxed-up model for layering composite increments Lingual shelves denote amber-whitish nuances, appears opalescence in natural enamel. A fine-tipped dental instrument was used to gently create the dentin mamelons. artificial dentine provide nature-mimicking color and opacity. Natural opalescence and deep translucency around and in between the mamelons.

35. Vita-based chromatic enamel was applied beyond the bevel line and contoured to create a seamless transition An achromatic enamel was placed over the lobes to promote higher opacity and color value After refinement and curing, replicating optical propertie s of natural enamel lobes The facial planes worked with finishing discs to establish the primary anatomy , to establish natural facial planes e mbrasures opened until symmetry was achieved Anatomy mapping was penciled in on the centrals to aid in attaining proper tooth morphology during finishing

36. Secondary anatomy was achieved with a flame-shaped, fine diamond bur to reduce volume and emphasize the proximal lobes. Tertiary anatomy was completed with a diamond bur at slow speed to create arch-like horizontal lines Worn blunt rubber rotaries were used to eliminate undesired texture and to impart a smoother appearance Specialized chamois and cotton wheels were used in the polishing steps to produce an enamel-like gloss Felt disc and aluminum oxide paste finalized the polishing, restorations achieved smooth and glossy surface. dentin and enamel composites selected for the buildups replicate the lifelike qualities of natural tooth structures.

37. DIFFERENT COMPOSITE AVAILABLE FOR CLINICAL USE IVOCLAR VIVADENT:- Nanohybrids:- Tetric N ceram Flowable composite: Tetric Flow 3M:- Nanohybrids:- Filtek Z350 XT Flowable composite:- Filtek Z350 XT Microhybrids:- Filtek Z350 Hybrid:- Z100

38. FACTORS AFFECTING COLOR PERCEPTION Light in the dental office of the observer Color blindness Metamerism Age Gender Experience Eye fatigue Position of the patient Time of the day Background colors

39.   Accurate shade selection that allows restorations to match the natural dentition positively influences the patients appearance and esthetic self-esteem. Patients are demanding contemporary esthetic dentistry, which has prompted the industry to continuously raise the bar with regard to esthetic detail From the preceding discussion, it is clear that tooth shade selection is a highly complex process that requires an interaction of scientific, physiological, psychological and artistic factors for an accurate outcome. Scientific principles related to light and color play a key role in determining the tooth shade perceived. CONCLUSION

40.   Mehta , kumar Goel m, Kumar , Arora t, Pande s, shade selection: blending of conventional and digital methods- an updated review. Johcd 2014;8 Dr. Vijayanti Lotwani , Dr. Mahesh Gandhewar , Dr. Shikha Gupta, Dr. Revathi k, Dr. Srikanth Reddy, a clinical approach to shade selection and communication Freedman G. Buyer‟s guide to cosmetic imaging systems. Cosmetic imaging creates projection of restorative treatment. Dent Today 2009;28(7):134-8. Glick K. Cosmetic dentistry is still dentistry. J Can Dent Assoc 2000;66(2):88-9 Jeannin T, Ubassy G. Anterior prosthetic restoration. Cah Prothese 1984;12(46):93-100.   Mukut seal, pratim talukdar , virag srivastav , kartik pendharkar , colour matching: a review of conventional and contemporary dental colour matching systems. 2014;2 Mayekar sm. Shades of a color: illusion or reality? Dent clinnorth am. 2001;45 REFERENCES