Shade guides Shade tabs Each shade guide consists

Shade guides • Shade tabs - Each shade guide consists of multiple shade tabs

Vita Lumin Vacuum Step 1: Hue matching - Four grouping of hue, A 1 -A 4 B 1 -B 4 C 1 -C 4 D 2 -D 4 Reddish-Brownish Reddish-Yellowish Grayish shades Reddish-gray - Match the samples with high chroma with cervical area of canines

Vita Lumin Vacuum Step 2: Chroma selection - Once the hue has been accomplished, a choice is made for the best chroma - For instance B is the best hue match then it has four different chroma: B 1, B 2, B 3, B 4, of the same hue

Vita Lumin Vacuum Step 3: Value selection - Finally, value is determined with a second commercial guide whose samples are arranged in increasing lightness (B 1 -C 4) - An observer will be able to assess the value most effectively by observing from a distance, standing slightly away from the patient, and looking through a squinted eye, reducing the light that reaches the retina. Stimulation of the cones is reduced and greater conditions to achromatic vision may result

Vita Pan 3 D Master • There are 5 lightness levels (plus an additional level for bleached teeth)

Vita Pan 3 D Master Step 1: Value - Select one out of the 5 value groups

Vita Pan 3 D Master Step 2: Chroma - Choose the appropriate chroma by using the M subgroup first and choosing between level 1, 2 or 3

Vita Pan 3 D Master Step 3: Hue - Choose the appropriate hue by choosing either more reddish (R) or more yellowish (L) - Available in two chroma for group 2, 3 & 4

Shade guides • Other available systems, - Extended shade guides - Dentin shade guide - Custom shade guide

Instrumental color analysis • Inconsistencies can result from factors such as physiological, psychological, age & fatigue • Instrumental color analysis is an alternative offering objective, quantifiable & more rapidly obtained shade matching • Various color measuring instruments exist: colorimeters, spectrophotometer, and digital image analyzers

Instrumental color analysis • Colorimeters, spectrophotometer are unsuitable for routine dental use because of their limited ability to measure the color of translucent objects • In addition, colorimeters are adapted for flat surfaces and not curved teeth surfaces

Instrumental color analysis

Surface characterization • Stains can be added to the surface of the restoration to produce better tooth integration & natural appearance • Used only for minor changes, to achieve: 1. Shade modification 2. Specific characterization 3. Special illusions of form or position

Shade distribution chart • The tooth is divided into three regions: cervical, middle & incisal

Surface characterization • Advantages - Dentist can modify the shade after completion of the restoration • Disadvantages - Stains are applied to the surface only (unrealistic) -If excessive can cause loss of fluorescence & increased metameric effect - Restoration becomes slightly rougher - Stains are soluble & wear with time

Shade modification a. Chroma & Hue adjustments • Increasing chroma and changing hue • Pink purple moves yellow toward yellow red, yellow decreases red to yellow red • If we desire to decrease the chroma we usually use the complementary colors (yellow requires bluepurple & orange, blue-green) however rarely successful

Shade modification b. Value adjustments • Can be reduced by adding complementary color (violet for yellow) • Increase the value if the dominant color has a greater lightness such as staining with white but the opacity will increase & rarely successful

Specific characterization • Hypocalcified areas • Proximal colorations • Enamel cracks • Stained crack lines • Exposed incisal dentin • Incisal halo • Translucency

Specific characterization

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