Custom shade guide system for composite resins

Visual and digital tooth shade selection methods, related effective factors and conditions, and their accuracy and precision: A literature review

OBJECTIVE

Despite developments of dental shade selection methods, shade selection is still a challenge affecting esthetic outcomes. The purpose of this review was to discuss visual and digital shade taking methods, related effective factors and conditions, and their accuracy and precision to find out the most accurate, precise shade selection method available in dentistry.

OVERVIEW

The key terms of accuracy, background, ceramic, color, colorimeter, color analysis, color science, color measurement, color measuring instrument, color matching, composite resin, dental/tooth shade guide, digital camera, esthetics, imaging, imaging application/program/ software, intraoral scanner, light source, photography, precision, shade, shade matching/ determination/prediction/reproduction/selection, shade taking device, spectrophotometer, spectrophotometry, tooth color measurement, tooth color/shade, and visual perception were used separately and jointly to detect related English-language articles published between January 1, 1985, and January 1, 2021. Electronic/non-electronic searches of Google Scholar/PubMed/Scopus/Web of Science were accomplished. Consequently, 249 articles were considered. Accordingly, the digital methods show higher accuracy and precision compared to the visual methods while requiring to be enhanced regarding accuracy to achieve ideal shade taking results.

CONCLUSIONS

Dental spectrophotometers provide the highest overall accuracy and precision among different shade selection methods while needing clinical setting to control related effective factors/conditions and technological improvement to perform optimally.

CLINICAL SIGNIFICANCE

Different factors can affect the accuracy and precision of tooth shade selection methods and devices. The understanding of these effective factors may lead to a standard shade taking protocol using accurate, precise methods and devices.

Appearance Differences Between Lots and Brands of Similar Shade Designations of Dental Composite Resins

OBJECTIVES

The purposes of this study were to investigate differences in two inherent appearance characteristics between lots of an enamel dental composite resin of the same shade and brand, and to further compare these differences to those of similar shade designation of a different brand of dental composite resins.

METHODS

Appearance analyses proceeded for three different lots of shades A1, B2, and D3 manufactured by one company and for one lot of shade EA1 manufactured by another. Samples were measured on black, white, and gray backings using spectroradiometry. Kubelka-Munk theory was used to determine reflectivity of each lot studied. CIELAB values and color differences between shades and lots were analyzed. Translucency indicators were compared between lots over thicknesses from 0.5 to 3.0 mm.

RESULTS

Differences in inherent color between some lots of same shade designations within a brand were found to be above the acceptability threshold. Color difference between an enamel composite resin of shade A1 and a composite resin of shade EA1 was also above the acceptability threshold. Statistically significant differences in the translucency were found between some lots of one shade over the entire range of thicknesses studied.

CONCLUSION

Appearance analyses indicate substantial variation between lots of same shade designations as well as between brands of similar shade designations.

CLINICAL SIGNIFICANCE

Optical principles applied to important clinical appearance attributes are described which characterize inherent appearance attributes and provide aid in the appearance matching process for dental composite resins used in restorative and operative dental procedures. (J Esthet Restor Dent 29:E6-E14, 2017).

Shade compatibility of esthetic restorative materials--A review

OBJECTIVES

The objectives of this study were to review the shade compatibility of esthetic restorative materials and to provide a visual method to harmonize the color of them.

METHODS

Published reports on the color ranges and distributions of shade guides, color differences between restorative materials and the referenced shade guides, and those between the identical shade designated restorative materials were reviewed.

RESULTS

Several limitations in shade guides should be considered in color matching such as (1) color ranges and distributions of shade guides are different from those of human teeth, (2) arrangements of shade tabs in shade guides are not ideally logical, and (3) color of marketed esthetic restorative materials and the referenced shade tabs is significantly different. Color coordinates of restorative materials of the identical shade designations vary by the kind and brand of the restorative materials. Color differences between restorative materials and the referenced shade guides and those between the identical shade designated restorative materials are generally higher than perceptible limits. A visual color harmonization method was suggested, and the considerations for the instrumental color harmonization were provided.

SIGNIFICANCE

Visual color matching would result in color mismatching by the kind and brand of the restorative materials. The first step to improve the color matching performance would be the harmonization of the color of restorative materials with those of the corresponding shade tabs.