Quantitative and Qualitative Assessment of Fluorescence in Aesthetic Direct Restorations

Abstract

Currently available direct restoration materials have been developed to have improved optical properties to interact with light in the same manner as the natural tooth. The objective of this study was to investigate the fluorescence of different enamel resin composites. In the present study, nine brands of enamel composites were tested in vitro, some of which are cited by manufacturers as having color adjustment potential. Fluorescence spectra of the composite specimens and the human natural enamel were measured with a fluorescence spectrophotometer immediately after preparation and after 6 months. Qualitative data of the specimens were also collected. Statistical analyses were conducted by Kruskal−Wallis and Mann−Whitney U nonparametric tests (p < 0.05). Almost all tested resin composites presented a significant decrease in the fluorescence values after a period of 6 months. There was no significant decrease in fluorescence in the case of Harmonize™ resin composite samples, which presented the lowest initial fluorescence values. The highest value in the reduction of the initial fluorescence intensity after 6 months (22.95%) was observed for the Charisma® specimens. Composites with a color adjustment did not perform significantly better than other composites in terms of reduction in fluorescence intensity.

Keywords: dental materials; enamel; fluorescence properties; resin-based composite; restorative materials.

Figure 1

Fluorescence of a premolar slice (in 385 nm UV light). The digital equipment used was a DSLR camera (Nikon D3100, Nikon Corporation, Tokyo, Japan) equipped with a macro objective (Tamron 90 mm), ISO 200, f/22, exposure time: 1/200 s.

Figure 2

Image of a cross-section premolar slice in UV light (385 nm), revealing the differences in fluorescence between dental tissues and a restoration with Charisma^®. The digital equipment used was a DSLR camera (Nikon D3100) equipped with a macro objective (Tamron 90 mm), ISO 200, f/22, exposure time: 1/200 s.

Figure 3

Column graph of the fluorescence intensity values (in arbitrary units) from the first measurement, representing the mean and standard deviation (SD) of each type of composite and the enamel.

Figure 4

Column graph of the fluorescence intensity values (in arbitrary units) measured after 6 months, representing the mean and standard deviation (SD) of each type of composite and the enamel.

Figure 5

Samples under an ultraviolet light source showing the different fluorescence levels of the materials. Samples with different values: (a) low fluorescence (value 0); (b) medium fluorescence (value 1); (c) high fluorescence (value 2).