Shade Matching in Restorative Dentistry voluMe Iv

A key aspect in the ultimate success of a dental restoration, especially in the esthetic zone, lies in achieving accurate shade matching. A vital tooth is both naturally translucent and transparent, and it is crucial to understand the intrinsic difference between the tooth and dental porcelain for optimal results.

Disimilar from a natural tooth, dental porcelain has opaque properties, thus reflecting and absorbing but not transmitting light. There are three main areas that directly affect shade matching: the light source, the environment and the doctor or clinician. The pure reliance on matching to a shade tab is insufficient for proper shade matching. >>

Billy Schrader, CDTCrown & Bridge Technician

Billy Schrader is a Certified Dental Technician with over 19 years of dental lab experience. He is an expert in crown and bridge as well as ceramics.

6015 Benjamin Road | Suite 310 | Tampa, Florida 33634877-337-7800 | www.DDSLab.com

LAB-300167 R8-11 © 2011 DDS Lab. All rights reserved.

Light SourceThe light source will dramatically affect shade. The operatory light should not be pointed directly at the patient. Key aspects of ideal light for shade matching include:

• Indirect lighting with fluorescent bulbs at 5500 Kelvin color temperature

• Color corrected with a full visible spectra range

• Enough intensity to eliminate ambient light, but not so strong as to mask the color differences

• Pleasant to the eye in order to deter fatigue

• Consistent in that it does not change depending on time of day or location

The EnvironmentFrom floor to ceiling, the entire room or setting should have a neutral light gray background, not white. A patient’s lipstick, clothing, and clinical drape also can adversely affect the color perception. If needed, use a blue bib to relax your eyes.

Using PhotosPhotographs are not accurate or sufficient in color replication, but they can be useful for determining gradation and characterization. To achieve the optimal results, the following steps should be followed:

• Always have a shade tab in the photo so the technician can compare the difference in the Value and Chroma and make the needed adjustments.

• Use a camera with a macro lens and ring flash. This will allow you to get a closer and more detailed photo without having the flash alter the shade.

Shade Matching in Restorative Dentistry: Increase the esthetic success of dental restorations

DefinitionsChroma: the purity of a color. High chroma colors look rich and full. Low chroma colors look dull and grayish. Sometimes chroma is called saturation.

Value: Value, or lightness, varies vertically along the color solid, from black (value 0) at the bottom, to white (value 10) at the top. Neutral grays lie along the vertical axis between black and white

Shade Matching In Restorative Dentistry

6015 Benjamin Road | Suite 310 | Tampa, Florida 33634877-337-7800 | www.DDSLab.com

LAB-300167 R8-11 © 2011 DDS Lab. All rights reserved.

• If your camera doesn’t have a ring flash, have the patient sit up with their chin slightly tucked in. This will help keep the flash from reflecting in the picture.

• Use a room with some natural light if possible and avoid pointing any light directly toward the patient.

• It is important that color selection is done when the patient is first seated in the dental chair as Chroma and Value can change due to minor dehydration after the patient’s mouth has been open for a period of time. Studies show that teeth can take more than 24 hours to return to their natural state. Additionally, there is less chance for optical fatigue.

• The patient should be reclined at a 45% angle with the patient’s mouth level with the dentist’s eyes. Shade guide tabs should be applied parallel to the tooth, never in front or back.

• Diagrams should be used. A facial view of the clinical crown is used to indicate the position of the various shades, while a proximal view shows the technician how the body and enamel porcelains should be layered.

• The amount of reduction is the most important factor in creating esthetic restorations. 1.5mm - 2.0mm is recommended in order to have adequate porcelain thickness for proper shade matching.

• The 5 Second Rule - limit viewing to 5 seconds, as eye fatigue will set in. Your initial decision is usually the most accurate.

Need an expert’s advice? We’re available for a consultation on your cases. Call us at 877-337-7800.

Shade Matching in Restorative Dentistry: Increase the esthetic success of dental restorations

Color perceptionColor perception varies from fractionally to drastically by individual depending on their vision. Women are far less likely (.5%) to be color blind than men (8%). All doctors and technicians should take a color vision deficiency test such as Ishihara or Farnworth Lantern annually as vision can change.

This is a sample of the Ishihara Color Test for red-green color deficiencies. It was named after its designer, Dr. Shinobu Ishihara, a professor at the University of Tokyo, who first published his tests in 1917.

Additional Tips

Shade Matching In Restorative Dentistry voluMe Iv