INFOGRAPHIC: How to Determine Accurate Shade in Dentistry

Shade matching is subjective and influenced by many different factors. An inaccurate shade is a common cause of remakes, as even the slightest difference between an actual shade and its perceived color makes a huge difference in the mouth and is unacceptable to the patient and clinician. Being aware of issues that can affect your perception of color, and knowing how to reduce their influence, allows you to take more accurate shades.

Below is a visual guide that walks you through the process step by step:

Before the patient arrives, make sure you have a shade guide available. Suggested shade guides include:

• Vita Classic
• Vita 3-D Master Shade Guide
• Bleach Shade Guide
• Chromascop
• Portrait IPN Shade Guide

It’s best to select the shade at the beginning of the patient’s appointment, before treatment begins. Take the shade soon after the patient is seated in the chair to reduce risk of the color being affected by minor dehydration. Teeth that become dehydrated during an appointment can change in chroma and value. 

• Chroma
  Chroma is the purity of color, so colors with a high chroma look rich and full. Colors with a low chroma look grayish and dull. Chroma may also be called saturation.

• Value
  Value is the lightness of a color and varies vertically along the color solid. Black has a value of 0, while white has a value of 10. Neutral grays are aligned along the vertical axis between black and white.

View the patient at eye level while taking their shade, and make the decision as quickly as possible.

Preparing the Correct Environment for Shade Taking

The entire room you use for shade taking should have a neutral light gray color. The walls can be a subdued color or a grayish to slate-blue tone. Avoid taking shades in a room with a white background, where the reflective light could adversely affect shade accuracy. Look around the room to ensure that there are no bright colors in your immediate field of view. When taking the shade, use neutral-colored gloves and provide a blue bib for the patient to relax your eyes. If the patient is wearing lipstick, ask them to remove the color and make sure their teeth are clean.

Choosing the Correct Light Source

Using the correct light source is vital when selecting a shade; the wrong type of light makes it virtually impossible to achieve a good match. Here are some things to keep in mind:

• Choose indirect fluorescent bulb lighting at 5500 Kelvin color temperature
• The bulb must be color-corrected with a full visible spectra range
• It should have enough intensity to eliminate ambient light but shouldn’t be so strong as to mask color differences
• The lighting must be consistent. It shouldn’t change with the time of day or the weather
• Make sure your lighting is pleasant to the eye; if you feel fatigued, you will be far less likely to take an accurate shade

Don’t aim the operatory light directly at the patient, as this could dramatically affect the shade.

Using Photos to Illustrate a Shade

Photos do not accurately replicate colors, but they are useful for showing tooth characterizations and illustrating color gradation in teeth. Your photos will be far more helpful if you include a shade tab in the picture. Including the shade tab allows the technician to assess the difference between value and chroma more accurately and to adjust materials, such as porcelain effect powders, as needed.

When taking a photo, use a camera with a macro lens and ring flash, because this allows you to take a more detailed picture without the flash affecting the shade. If you don’t have a camera with a ring flash, position the patient so that they are sitting up and have them tuck their chin slightly to reduce the risk of the flash reflecting in the photo. Most smart phones take great pictures in detail.

Color Perception

Color perception can vary fractionally or drastically from one individual to another. There are three types of color blindness in which color perception differs from normal vision and the eyes struggle to differentiate between certain colors. Most color blindness is inherited, and men perceive colors less accurately than women. Approximately 8% of men have some form of color blindness, compared to 0.5% of women.

1. Deuteranopia
   People with deuteranopia have green color blindness, which means that they have trouble differentiating between greens, browns, oranges, and pale reds.
   
   
2. Protanopia
   Protanopia is a form or red color blindness, in which red colors appear dull.
   
   
3. Tritanopia
   People affected by tritanopia have difficulty differentiating between blue colors.

Most people are unaware that they have any form of color blindness, and, in many cases, it will not affect their everyday lives. However, accurate color perception is vital for clinicians and technicians. Annual color vision deficiency tests, such as Farnworth Lantern or Ishihara, should be taken regularly, as vision can change.

Please don’t hesitate to contact us if you would like more information. Our skilled technicians have in-depth knowledge and are always willing to discuss specific cases.

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