Laser-induced fluorescence to discriminate between a dental composite resin and tooth

Digital image analysis of fluorescence of ceramic veneers with different ceramic materials and resin cements

The objective of this study was to analyze the effect of the type of ceramics and resin cements on the fluorescence of ceramic veneers under the 405 nm UV-light by digital imaging. One hundred and ninety-two veneers were fabricated using three types of ceramics (IPS e.max CAD, IPS Empress CAD, and Zenostar). Eight pieces of substrates were made of resin-nano-ceramic (Lava Ultimate). The level of fluorescence for each sample cemented with the substrate using three kinds of resin cements (RelyX U200, Variolink N, and Choice 2) was analyzed by using histogram data of luminosity from Adobe Photoshop software. Furthermore, the fluorescence values were evaluated by two-way ANOVA and Tukey's test. The highest fluorescence values were observed for the IPS e.max CAD cemented with Choice 2 cement, followed by IPS Empress CAD, and Zenostar the lowest. The final fluorescence intensity of ceramic veneer is affected by ceramic materials and resin cements.

The Effect of Feldspathic Thickness on Fluorescence of a Variety of Resin Cements and Flowable Composites

(1) Background: The shade of resin-based materials and ceramic thickness influence the optical color of laminate restorations. The purpose of this study is to evaluate—in vitro—the effect of resin-based cement shade and ceramic thickness on fluorescence of feldspathic laminate veneers; (2) Methods: 180 samples of feldspathic ceramic A2 shade with two different thicknesses (0.5 and 0.8 mm) were obtained. The samples were cemented to composite resin substrates with one of the following materials in different shades (n = 10): resin cement (Variolink Esthetic in Light, Neutral and Warm shades; or RelyX Veneer in B0.5 /white, Translucent and A3 Opaque/yellow opaque shades); flowable composite resin (G-aenial Flo in A2 and A3 shades) or a pre-heated composite resin (Filtek Supreme XTE, A3 body shade). The fluorescence spectra were obtained by means of a spectrofluorometer. Two-way ANOVA, Tukey, and Student’s t-tests were performed (α = 0.05); (3) Results: Fluorescence values were significantly influenced by the resin-based agent tested (p < 0.001), the thickness of ceramic (p < 0.001), and their interaction (p < 0.001). The lowest fluorescence values were achieved by RelyX Veneer resin cement regardless its shade and the ceramic thickness; (4) Conclusions: both the shade of resin-based agent and the feldspathic ceramic thickness influenced the fluorescence of laminate restorations.

Differences in the intensity of light-induced fluorescence emitted by resin composites

BACKGROUND

The aims of this study were to compare the intensities of fluorescence emitted by different resin composites as detected using quantitative light-induced fluorescence (QLF) technology, and to compare the fluorescence intensity contrast with the color contrast between a restored composite and the adjacent region of the tooth.

METHODS

Six brands of light-cured resin composites (shade A2) were investigated. The composites were used to prepare composite discs, and fill holes that had been prepared in extracted human teeth. White-light and fluorescence images of all specimens were obtained using a fluorescence camera based on QLF technology (QLF-D) and converted into 8-bit grayscale images. The fluorescence intensity of the discs as well as the fluorescence intensity contrast and the color contrast between the composite restoration and adjacent tooth region were calculated as grayscale levels.

RESULTS

The grayscale levels for the composite discs differed significantly with the brand (p<0.001): DenFil (10.84±0.35, mean±SD), Filtek Z350 (58.28±1.37), Premisa (156.94±1.58), Grandio (177.20±0.81), Charisma (207.05±0.77), and Gradia direct posterior (211.52±1.66). The difference in grayscale levels between a resin restoration and the adjacent tooth was significantly greater in fluorescence images for each brand than in white-light images, except for the Filtek Z350 (p<0.05). However, the Filtek Z350 restoration was distinguishable from the adjacent tooth in a fluorescence image.

CONCLUSIONS

The intensities of fluorescence detected from the resin composites varied. The differences between the composite and adjacent tooth were greater for the fluorescence intensity contrast than for the colors observed in the white-light images.

Fluorescence properties of commercial composite resin restorative materials in dentistry

The objective was to assess the fluorescence properties of current commercial resin composites. Sixteen light-curing resin composites, representing a total number of 241 shades, were analyzed. Fluorescence measurements of all samples were taken using the monochromator-based fluorescence reader Synergy(TM )Mx (BioTek Instruments Inc. ). Additionally, samples of dentin and enamel were analyzed for comparison. The mean of the maximum excitation wavelength was (398±5) nm and the mean of the resulting emission wavelength was (452±9) nm for all composite shades. The maximum fluorescence varied widely between 50 and 70,808 RFU with a mean of (28,948±15,380) RFU. The maximum for dentin was (9,308±3,676) RFU and enamel (5,467±506) RFU. The results showed that the analyzed composites fluoresced at nearly the same excitation-emission wavelengths combination but with varying optical intensities. These results provide useful reference for optimal fluorescence induction and may help to develop better fluorescence diagnostic methods needed for treatment, forensic investigations and epidemiological research/analyses.