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The dental laboratory needs many important pieces of information to produce exquisite esthetic results.

One of the most frustrating moments in a dental practice is trying in a restoration and realizing it doesn’t match. To help avoid that frustration, shade is part of my laboratory communication.

It’s important for clinicians to understand that three major components contribute to our perception of a tooth’s shade: value, chroma and hue. Value is the most critical of the three parameters when attempting to match an adjacent natural tooth; hue is the least important.

Assessing the situation

To assess the value of the tooth, we look at whether the tooth appears light or dark. This perception is controlled by the amount of light reflected back to our eye after it hits the tooth’s surface (Fig. 1).

Value is intimately related to the tooth’s surface morphology. The more surface texture that is present when light hits a tooth, the greater the amount of light reflected away from our eye. This makes the tooth appear darker or lower in value.

In contrast, a smooth surface allows a larger amount of light that hits the tooth surface to be reflected back to our eye. This gives the tooth a lighter appearance, or a higher value.

Clear communication

When communicating the value of a tooth to the laboratory, work with a shade guide that lists value as a separate parameter. Our eyes are better at judging value in a less illuminated environment. Turn off the dental operatory light, close the blinds and turn off the overhead lights. Allow your eyes a moment to adjust to the reduced light levels before choosing the shade tab that matches in value.

The color information filtered from our eyes to our brain can inhibit our ability to determine value. A digital image of the teeth that has been converted to grayscale will make the different values of teeth much easier to discern than if they were in full color (Fig. 2).

The Vita classic shade guide links the value and the chroma together. Try taking a digital photograph of your classic shade guide, converting it to grayscale and reordering the tabs from dark to light by value.

Lighting is everything

To increase our ability to accurately determine the chroma and hue of a tooth before we send the information to the lab technician, we need to have light that supplies a full spectrum of color wavelengths.

Some clinicians opt to choose their shades in natural daylight. The challenge with this method is, that even though it may work very well at noon on a cloudless day, taking your patients outside to the office parking lot to shade match usually isn’t very helpful.

It’s a good idea to set up at least one operatory with color-corrected bulbs in the overhead lights. When choosing color-corrected bulbs, look for a CRI rating of 100 and a 5500°K color temperature.

Stay neutral

Our eyes can tire of looking at and perceiving certain colors, or become confused in their ability to ascertain color. It is important not to expose our eyes to vivid red or orange colors before choosing the chroma and hue for a restoration.

I prefer neutral colors for our patient bibs, such as light blue or grey, because they are restful to our eyes and enhance our ability to perceive the parameters of shade selection. If patients are wearing a vivid lipstick, we ask them to remove it. If they are wearing vividly colored clothing, we cover it with a patient bib and allow a few moments to pass before completing our shade matching.

First things first

Desiccation of the tooth structure causes modified hue, less translucency, increased value and decreased chroma. To help avoid any potential problems, I obtain all shade information before commencing any dental procedures, and I do this for both indirect and direct esthetic restorations.

Accurate photographic information is difficult to obtain if the teeth are desiccated, so I take a set of digital images for the laboratory, including a set with shade tabs, before preparing the teeth. During the course of treatment, I take both stump shade images, as well as prepared teeth. This enables me to provide additional and valuable information to the laboratory.

Going natural

Many shade guides contain tabs that have been created to mimic natural teeth. They contain a chroma gradient; the true shade of the tab is only contained in the body portion (Fig. 3).

If you use this type of shade tab, consider a few things. First, using the incisal edge on this type of tab can help prevent color blending, which is a phenomenon that occurs when we see similar colors side by side. Our brain automatically blends the colors together, making them look similar.
By placing the dissimilar color of the incisal edge of the tab against the incisal edge of the tooth, we space the two colors we are trying to evaluate.

You can also eliminate the color gradient by spending a few minutes with your shade tabs and a lathe. Remove the sides and incisal edge of the tab, leaving the named chroma and hue behind on the slenderized shade tab. I keep a quantity of the most common shade tabs available.

After selecting the matching tab, I photograph the tab and the tooth together for the lab. I then send the exact tab used that day with the case to the laboratory.

The result

These steps can help you improve communication with your lab technician. Achieving better communication will lead to a more accurate shade match and less frustration when it’s time for try-in. Being on the same page with the laboratory will also lead to a better, more esthetic result your patients (Fig. 5).

Fig. 1 The perception of whether a tooth appears light or dark is controlled by the amount of light reflected back to our eye after it hits the tooth’s surface.	Fig. 2 Value grayscale appearance. A digital image of the teeth that has been converted to grayscale will make the different values of teeth much easier to discern than if they were in full color.	Fig. 3 Many shade guides contain tabs that have been created to mimic natural teeth and contain a chroma gradient. The true shade of the tab is only contained in the body portion.
Fig. 4 It’s important to have a conversation with your patients about whether they want a chroma gradient included or if they prefer a uniform appearance.	Fig. 5 Communicating shade with your laboratory technician will help lead to more esthetic outcomes for your patients.