Guidelines for Visual Shade Selection

Before beginning the process of shade selection, it is important to understand and follow the recommended guidelines for achieving a consistent and accurate result.^11,39

Step 1: The tooth/teeth of interest should be cleaned free of deposits and surface stains.^11,39

Step 2: A color-corrected light source with a CRI > 90 and a color temperature of 5500K should be used for shade selection. In addition, the shade should be evaluated under different types of lighting after the initial shade is chosen in natural daylight/color-corrected light.^11,39

Step 3: A neutral-colored environment should be utilized for shade selection. Bright clothing, vividly colored operatory walls, and/or make-up can alter color perception. If the patient’s clothing/ornaments are overly bright, it is advisable to use a drape to mask the undesirable colors (Fig. 16).³⁹ The patient’s makeup should be removed and all the dental instruments creating reflection must be cleared from the surroundings.³⁹

Fig. 16 - Bright-colored clothing may alter color perception during shade selection (left), a drape is used to mask the undesirable colors (right).

Fig. 16 - Bright-colored clothing may alter color perception during shade selection (left), a drape is used to mask the undesirable colors (right).

Step 4: The practitioner should be positioned in front of the patient, aligning the patient’s teeth with their eye level (Fig. 17).³⁹ A distance of 2 to 6 feet from the oral cavity is considered ideal for visual shade selection and the shade guide should be held at the patient’s mouth at arm’s length. To detect subtle differences in hue the practitioner may need to move closer to the patient; however, shape, value, surface texture, luster, and opacity can be assessed from a distance of four or five feet.¹¹

Fig. 17 - During shade selection, the patient is positioned at the eye level of the operator.

Fig. 17 - During shade selection, the patient is positioned at the eye level of the operator.

Step 5: Shade selection should be performed at the beginning of the appointment as the eyes are fresh.³⁹ If shade selection is performed after performing a crown preparation (Fig. 18), the eyes are tired and the adjacent teeth are dehydrated thereby resulting in errors in shade determination.

Fig. 18 - The adjacent teeth become dehydrated following tooth preparation.

Fig. 18 - The adjacent teeth become dehydrated following tooth preparation.

Step 6: Practitioners should not stare at the tooth/teeth for a long time as it may result in hue accommodation. The process should be completed in 5-7seconds; If it is taking longer, the practitioner must “reset” his/her eyes, by looking at a neutral gray-colored surface/object.^11,39

Step 7: The visual method of shade selection involves the use of shade guides (Fig. 19). The middle third of the tooth and the shade tab should be used as a reference for hue determination (Fig. 20). The incisal edges are generally more translucent and lighter than the middle third of the teeth, hence, they may result in the selection of an inaccurate hue.

Fig. 19 - Vita classical shade guide

Fig. 19 - Vita classical shade guide

Fig. 20 - The middle third of the tooth and the shade tab is used as a reference for hue determination.

Fig. 20 - The middle third of the tooth and the shade tab is used as a reference for hue determination.

Fig. 21 - The shade tab is positioned such that the incisal edge of the shade tab approximates the incisal edge of the tooth of interest.

Fig. 21 - The shade tab is positioned such that the incisal edge of the shade tab approximates the incisal edge of the tooth of interest.

The shade tabs should be positioned at the same angle as the tooth of interest. The shade tab is placed such that the incisal edge of the shade tab approximates the incisal edge of the tooth of interest (Fig. 21).^52,53 This helps prevent the reflection of the teeth and the shade from falling on each other. The laboratory must be familiar with and use the same shade guide as the practitioner.¹¹

Step 8: The appearance of teeth is mostly determined by how light interacts with the curved and varied surfaces of the tooth, hence, it is recommended to use multiple viewing angles during shade selection.⁷

Step 9: The teeth should be dry while assessing value, translucency, surface texture, and luster, and moistened while evaluating hue and chroma to limit the influence of surface morphology.⁷

Step 10: Shade selection should be performed before the application of the rubber dam to prevent tooth dehydration.⁴⁸

Step 11: It is recommended to avoid performing shade selection immediately after the application of a curing light as it also leads to dehydration of teeth.

Step 12: If a bleaching procedure is performed on the teeth, it is recommended to schedule shade selection after 30 days to permit enamel rehydration.⁵⁴