The selection of color in dentistry direct restoration

OBJECTIVES The aim of this article is to help the clinician refine the knowledge on the optical properties of dental elements, on composite shades and how to detect them from the teeth that have to be restored, in order to select the appropriate shades for the restoration. MATERIALS AND METHODS The color is identified through its chromatic (tint, chroma, value), achromatic (gloss, opacity,transparency, translucency) and optical phenomena (translucency and opalescence) properties. The real problem, however, has always been to rationalize the color so that it could be coded numerically and then rationally compared to others. Thanks to the color spaces it is possible to measure, to classify and to reproduce the color itself. The most widespread system is called CIELab*. In dentistry, there are various systems to detect color for direct restorations, including commercial shade guides and custom shade guide. Currently, electronic instruments, such as colorimeters and spectrophotometers (e.g. VITA Easyshade, VITA Zahnfabrik, Bad Sackingen, Germany; Spectoshade-Micro, MHT, Niederhasli, Switzerland) are also widely used, and they allow to detect the base color and then to convert it into data, in order to eliminate the subjectivity, increasing the level of consistency. The dentist can also use other tools (pictures and oral scanners) to understand better teeth's color. Another method analyzed is to apply, without any adhesive system, composite shades on the element to be restored, polymerizing it and assessing whether or not there are any matches, according to the technique defined as "button-try". RESULTS This article shows that the most indicated color detection methods are custom shade guide and the "button-try". However, the latter technique has limits if we have to select translucent shades (enamel) while the effects are only visible when polymerized on an opaque substrate. An important and fundamental contribution is also provided by the knowledge of the optical properties of the materials available to the clinician. CONCLUSIONS Selecting the correct shades in anterior direct restorations is always a challenging procedure. The techniques used to obtain color information and to perform a shade selection are described in this article. CLINICAL SIGNIFICANCE Selecting the correct shades can improve esthetic outcomes of direct restorations and reduce time for correction.