Some patients may be surprised to know that many dentists consider themselves artists as much as medical professionals. And it’s no wonder: when it comes to creating beautiful and healthy smiles, dental care is a blend of art and science, especially when it comes to repairing broken or decayed teeth with a dental crown (a.k.a cap).
Matching the color of teeth may sound tricky and it certainly is. After all, compared to the entire color spectrum of the natural world, human teeth occupy a pretty narrow range of yellowish off-white color. Luckily, there are a lot of time-tested techniques, science and modern technology to help the dentist make aesthetic decisions.
Dentists and dental technicians refer to teeth has having a shade, not a just a color. A shade includes hue, chroma and value. Hue is the same thing as color. The hues found naturally in teeth are yellow, red, or gray. Chroma is the saturation or intensity of the hue. Value is how light or dark the shade is.
The most common tool for color matching is a shade guide, a metal or plastic card with fake porcelain teeth of many shades arranged in a particular order. The dentist will hold the guide by your teeth and compare the natural shade to the examples until a similar shade is found. The dentist usually starts by determining the value of the tooth, and then finds the hue and chroma.
While the choice of a shade is somewhat subjective, there is some science that can help. Color decisions should be made under natural light conditions (such as near a window) or under fluorescent lights that mimic natural light. Regular incandescent lights tend to be too yellow and can make colors appear differently. Patients may be asked to remove any bright lipstick or other makeup, as this can affect the perception of tooth shade.
If you are wearing bright colors, the dentist may drape you with a gray bib. This has two purposes: it reduces the any color contrast that may come from bright clothing, and it gives the dentist’s eyes a neutral place to rest between looks at your teeth and the shade guide. The eyes need to rest because the rod cells in your eyes, which perceive color, can get tired quickly. The dentist will only look at your teeth for seven seconds at the most before looking away at something neutral or gray to reset the rods.
Next, the dentist may ask you or a colleague for a second opinion. Because color perception can vary slightly from person to person, having more than one opinion can reduce the chance for inaccuracy. Technology also offers a less subjective way to test color. Dentists can use a small electronic device called a spectrometer, which uses sensors to interpret the color of teeth.
Finally, the dentist will carefully note the shade of your teeth, often including drawings and digital photos of both your existing teeth and the one that is being prepared for a dental crown. This information then goes to a dental laboratory, where an expert ceramist creates the crown. It should be noted that an absolutely perfect match between two teeth is nearly impossible. However, very good matches with nearly imperceptible differences are common. If there is a problem with the color of the crown, the dentist can send it back to the lab for another try, but we always strive to get it right the first time!