BAZOS/MAGNE
Luster Luster describes the qualitative correla- tion of the visual appearance produced by the reflection of light with the enamel surface. Also known as contrast gloss, luster can be somewhat subjective, ex- pressed in relative terms such as satin- like, pearly, metallic, glass-like (Fig 8).
sequently producing an elevated light- flux density concentration at this junc- tion, 25,26 while the underlying mantle dentin exhibits low tubule density and small tubular size, providing minimal scattering. Furthermore, the change in the RRI between dentin and enamel re- sults in partial reflections of light at this junction and theoretically, when condi- tions are favorable for short distances, localized total internal reflections may be attained.
Objective color elements
Hue Hue Is defined as the name that distin- guishes one family of colors from an- other. Hue is specified as the dominant range of wavelengths in the visible spec- trum that yields the perceived color. 27 The base shade of dentin primarily de- termines the hue of a tooth. 28,29 Hue can be considered the quality of pigment (Figs 9 and 10). Chroma Chroma is defined as the saturation, intensity, or strength of the hue. Unlike value, which occurs independently of hue, chroma is only present when there is hue. 30 Chromaticity is an objective specification of the quality of a color regardless of its value, that is, as de- termined by its hue and chroma, and is readily visualized via cross-polarized reflective photography (Figs 9 and 10). Value Value is defined as the relative white- ness or blackness of a color and is de- termined by comparing it to a gray of similar brightness. Value is also called lightness, brightness or luminance (Figs 9 and 10).
The nine elements of visual synthesis
Descriptive surface elements
Surface texture Surface texture describes the physical characteristics of the enamel surface, being directional (vertical developmen- tal lobes/horizontal cervical ridges) and structural (perikymata). Perpetual sur- face texture adaptation is a function of the inherent microstructure at eruption and the subsequent physical and chem- ical processes that modify it: attrition, abrasion, and erosion (Fig 8). Gloss Gloss describes the visual perception based on the interaction of light with the physical characteristics of the enamel surface, relating to the ability to reflect light in a specular (“glossy appearance” observed on polished convex con- tours) or diffuse (“matte appearance” observed within concave depressions) manner. Like color, it exhibits physical, physiologic, and psychological aspects (Fig 8).
339 THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY VOLUME 9 • NUMBER 3 • AUTUMN 2014
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