Opalescence
NobelRondo™ ceramics' special production process also contributes to achieving natural opalescence, even after multiple firings. Very fine particles,
distributed homogeneously throughout the structure of the ceramic, create an unusually beautiful, soft opal effect. Above all,
the recent development of “Mother-of-Pearl” modifiers makes very natural opalescent contrasts possible.
One of the most beautiful optical phenomena with natural teeth is the opalescent gleam of the enamel. This opalescence comes
about through the dispersion and refraction of daylight into the smallest particles or structures. The dental enamel reflects the shortwave-length
blue portion of light, transmits warm, long wavelength orange-colored light, and glows in the transmitted light almost like amber. In mineral opals,
this iridescent, milky lightness in reflected light, and the reddish color play in transmitted light, are caused by tiny water inclusions and impurities.
In natural teeth, it is the prisms of the inorganic enamel that bring forth this effect.
 |
NobelRondo™
opalescence in reflected
and transmitted light |
 |
Fluorescence
The natural fluorescence comes from the depths of the tooth. Ultraviolet light, as electromagnetic radiation from the non-visible spectrum of daylight, stimulates this particular form of luminescence.
The emitted radiation has a longer wavelength and less energy than the absorbed light radiation. The impinged light increases the energy of an electron so that it rises to an excited and unstable energy
level and then falls back to a lower energy level by emitting radiation. Sir George G. Stokes discovered this phenomenon in fluorite, a fluorescing mineral, in 1852. The ceramic compound that is built up
in the inside of the crown is also dosed with additional fluorescing material. This produces a natural glow from the center of the crown, even in varying light conditions.
 |
Section through natural
premolar - reflected
and UV-light |
 |
Clinical Examples 
