dimanche 17 avril 2011

What Shade Are Your Teeth? Teeth Whitening Shades Explained



If you've been thinking about whitening your teeth with a dentist, some of the first things he or she will want to do are: determine the existing color of your teeth, whether or not you're a candidate for whitening and how white your teeth may be bleached. All of this, of course, depends on being able to describe the color of your teeth as they appear now.

Years ago, there was no standard way for dentists to describe the color of a patient's teeth - let alone communicate it to patients or porcelain manufacturers to ensure a match and a normal-looking smile. But with the growing popularity of cosmetic dentistry, the business of "shade management" is alive and well - and finding ever more sophisticated ways of identifying and communicating tooth color.

Hue, Chroma, and Value


While today's dental schools (and manufacturers of shade management systems) are now discussing tooth coloration and its identification in much more detail, the basics have been taught for years. Known as the Munsell method, all tooth colors are based on three criteria: hue, chroma and value.

Hue - is the underlying color of existing teeth compared to color groupings of brown, yellow, grey and reddish-grey.

Chroma - is the intensity of the underlying color

Value - is the black/white value of a tooth's appearance, or how bright it appears to be.

Dr. Shane Vania of Boise, Idaho states, "When I evaluate somebody's teeth for whitening, I first look at the hue and that tells me whether or not the whitening will have a good effect."

So, if you can whiten your teeth, how white will they be? Results are subject to their existing undertone. According to the American Dental Association, people who have a yellow undertone have higher degrees of whitening success than people with a brownish undertone. For people with gray undertones, however, there's some disappointing news. These teeth are generally the least responsive when it comes to bleaching. 

A Master Plan


But how white is white for your particular teeth? To determine the coloration of your teeth, your dentist will most likely utilize a shade management system. Today's shade management systems are based on either visual observation or digital matching criteria, an up-and-coming technology, especially in the areas of veneers and restorations. Shade management systems are critical because they let your dentist communicate the color of your teeth to staff members and refer to it when selecting whitening options for you. With a shade management system, your dentist can also show you the color of your teeth now - and your expected whitening results.

If your dentist is using a visual observation system, chances are he's relying on a "shade guide". A shade guide features differently shaded ceramic reproductions of individual teeth, grouped together and labeled for referral and categorization.

The most commonly used shade guides are made by Vita and are available in three basic styles: Vita Basic or Classic Shade Guides, the Vitapan 3-D Master® Shade Guide and the Extended Shade Guide for use when determining optimal shades for whitening.

The Vita Classic Shade Guide is really two guides - one guide is used to determine hue and chroma (in that order), while a separate guide is used to determine value. With The Vita Classic Shade Guide, the shade tabs or teeth reproductions are shown in groups of similar hues within the holder. The A shades are brown, B shades are yellow, C shades are grey and the D shades reddish-grey. A tooth's chroma (or color intensity) is then identified with a number from 1-4. To determine the value (or brightness) of a tooth, a value shade guide is needed. 

The Vitapan 3-D Master® Shade Guide system consists of 11 sets of fired porcelain tooth-shaped samples. The 11 sets consist of 26 shade tabs ranging from lightest to darkest value, from lowest to highest intensity and from yellow to red. Samples are arranged in groups of two or three that form five sets (numbered 1 through 5). Each set represents a single value, 1 being the lightest tooth color and 5 the darkest. 

Chroma and hue are represented within each value set. Using this guide, the value, or lightness, of the tooth color is the first selection made by the dentist. The chroma, or color saturation, is identified next by determining which of the hues in the group matches the tooth color. The hue is identified by selecting the color samples to the right or left of the M (median) hue (right indicates R and left indicates L tones in the tooth color).

The Vita Bleachguide 3D-Master® offers dentist a look at 15 bleached shades of teeth to help determine precise targets for whitening procedures, including a superior way to determine a patient's exact results based on hue, value and chroma. To distinquish the Bleachguide from the other Vita guides, bleached shades are described with a three-number ID code to establish their numerical classification, as in: 010, B020, B030, B040 etc.

While Vita is only one of many manufacturers of shade guides, they are generally considered to be the leader in this technology. Vita is now also developing products and systems to assist with digital color matching - considered to be the future of cosmetic dentistry.

The Digital Revolution


Despite a controversy involving its effectiveness, digital technology is being pursued by both manufacturers and dentists who are looking for even more precise ways to determine a tooth's existing color - and its potential for bleaching and other cosmetic procedures.

With digital technology, a hand-held "digital shade-taking device" is held up to the tooth, and by using artificial vision technology, a scanning unit measures, maps and communicates the essential parameters of the tooth color to a computing source. Digital Shading allows for a constant and accurate feed of light source on the tooth at all times. In return, the outcome is a standard color because the light source is being generated directly from the shade-taking device. There is the same light illumination at all times, allowing equipment makers to standardize the color for a much better interpretation. Once the picture of the tooth is taken, it is saved, uploaded and printed out. A colorimeter, the software inside of the scanner, determines the color. The entire process from start to finish is done in less than one minute. Not only does this method make identifying shades objective and consistent, it allows for a digital record of shades.

Getting the Right Match


  • If you know you're seeking a whitening consultation, dress in neutral colors. Strong colors can reflect on to the surface of your teeth - making a match more difficult.

  • Don't wear heavy facial make-up or lipstick - again, this can confuse the dentist's perception.

  • Clean your teeth well the day of your appointment.

  • Ask your dentist to perform the match at the beginning of your session so he or she can avoid eye fatigue

  • Make sure the walls of your exam room are a neutral color and that the dentist looks at your teeth at eye level to assure the best results.

  • If you are unsure about how white you should go or how it might look, try out our teeth whitening simulator for the iPhone.

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