Color Metamerism in Teeth
Color metamerism in
teeth is a phenomenon that needs to be taken into account in cosmetic
dentistry, when matching shades. Teeth
are made of hydroxyapatite. Composite bonding materials are made of
organic resins impregnated with inorganic fillers. Porcelain and other
ceramics are composed of different materials. Each of these materials has
its color properties. It is not uncommon at all for a tooth restored to a
shade match under one lighting situation to not match under different
lighting. (See
http://www.mynewsmile.com/horrorstories/porcelainveneermatch.htm.)
If a crown or bonding material is created to
match a tooth under warm fluorescent lighting, or incandescent lighting,
the color metamerism properties of the restorative material can easily
mean that the color will not match under a different light source, such as
outdoor lighting. For best results, shade matching should be done either
in the natural light from a large window with a northern exposure, or
under color-correct fluorescent lighting. There are several companies that
sell full-spectrum lighting. This lighting will be at a color temperature
of 5500 Kelvin. The Durotest Vita-Lite is the original bulb manufactured
to these specifications, but there are competing brands now that do the
same thing. Matching colors under a full-spectrum light source should
eliminate complications from color metamerism.
There is an excellent book with accompanying
CD-ROM that trains dentists to deal with
color metamerism and other complex color issues:
Esthetic Color
Training in Dentistry.
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