One of the common challenges I face daily as a restorative dentist is shade matching. Teeth have different layers of color that allow for variances not only in color but also in translucency. By eliminating or managing these variables we can greatly increase the predictability of matching shades.
For me one of the biggest variables are that teeth change color as they dehydrate. Also, the variances of lighting used to take and evaluate the shade need to be considered. And perhaps the hardest variable to control is our individual perception of color.
To manage the problem of dehydration of teeth and the subsequent color shift the first thing that you do is take your shade. It's also critical that you take care to keep teeth hydrated during try-in appointments to accurately evaluate the shade.
In addition to not allowing teeth to dehydrate it's important to have proper lighting. Ideally, you should have daylight bulbs changed on a regular basis in the room you are evaluating shades; it's often helpful to use natural light.
While the factors of color shift due to dehydration and the ambient light in the room are fairly easy to manage, much more difficult to manage is our individual perception of color. After all, what really is A-1 or 1M2?
How do we know and why? Do our brains all see the same A-1 or 1M2? It has been proven our eyes actually adjust to shade variances if we stare at two objects of different shades. If the shades are close and we look long enough, our brain can tell us the two shades match even if they are a little off. To combat this illusion, don't look at the shades you are trying to match for more than 10 seconds. Also look at a blue background periodically to help your eyes and brain "re-set." Another tool I've found helpful to achieve a predictable base color is the Vita Easy Shade; either my assistant or I can take predictable color independent of the operator perception or ambient lighting.
Finally, when working with a lab, it's important that you agree which shade systems work best based on the materials used. Some labs prefer the Vita Classic shade guide (A-1 or A-2) while others prefer the Vita 3-D shade guide (1M2 or 2M2). Once you know what shade system they prefer you can help them immensely by taking a picture of the selected shade tab next to the teeth you are matching.
John R. Carson, DDS, PC, Spear Visiting Faculty. [ www.johnrcarsondds.com ]