BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI
buletinul institutului politehnic din iaşi - Universitatea Tehnică ...
buletinul institutului politehnic din iaşi - Universitatea Tehnică ...
- No tags were found...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
52 Irina Grădinaru et al.<br />
from these findings, to the color characterization and transmission in dental<br />
laboratory is a long and difficult way .<br />
This paper presents a synthesis of data from the literature concerning<br />
color which, together with translucency, gloss and fluorescence, contributes to<br />
the aesthetic qualities of dental restorations.<br />
The color of a natural dental structure is influenced by the thickness of<br />
the enamel and the color of the subjacent dentin. Similar considerations can be<br />
applied to dental restorations with layered structure (eg porcelain restorations<br />
which are composed of body porcelain over inner opaque porcelain and resin<br />
composites over more opaque resins). In case of these layered structures, diffuse<br />
reflectance and the relationship between the translucency and thickness of the<br />
outer layer and the color and reflectance of the inner layer represent challenges<br />
to esthetic concerns (Fig.1). The outer translucent layer acts as a light-scattering<br />
filter over the inner layer. As the thickness of the outer layer increases, the<br />
effect of the inner layer is diminished. Similar situations exist when the<br />
translucency of the outer layer decreases (Bratu, 1994; O’Brien, 2008).<br />
Fig.1 – Porcelain–fused-to-metal indirect restoration: optical considerations<br />
after O’Brien.<br />
Color is considered a subjective phenomenon which can be regarded<br />
differently by different observers.<br />
Color may be produced in several different ways, including: selective<br />
reflection, selective absorption, diffraction, scattering, interference.<br />
The color of an object or a dental material result from a number of factors<br />
including: the composition of the material, its thickness, the surface<br />
roughness; the nature of illuminating light (McCabe & Walls, 2008).<br />
The translucency of an object represents the amount of the incident light<br />
transmitted and scattered by the respective object. A color which has a high