Base monomer and filler fraction combo determine colour and translucency of experimental composites

Researchers conducted a study to derive the K-M optical coefficients of experimental composites and compare the inherent CIE L*, a* and b* color parameters, translucency parameters and both perceptibility and acceptability thresholds.

Experimental composites were prepared with 4 base-monomers: Bis-GMA, UDMA, Bis-EMA and Fit852 with TEGDMA used as a co-monomer and 3 filler:resin fractions (50:50wt%, 60:40wt% and 70:30wt%). The optical absorption (K) and scattering (S) coefficients over the visible spectra were derived. Corrected reflectivity spectra were calculated using the corrected Kubelka-Munk reflectance model and were used to calculate CIE color parameters (X, Y, Z) values. Translucency parameter (TP) was calculated using the CIEDE2000 color difference. A three-way repeated measures ANOVA was used to analyze the CIE L*a* and b* color parameters at infinite thickness. A two-way ANOVA was used to analyze the translucency parameter at 2 mm thickness. Pairwise comparisons were assessed using Bonferroni-corrected Student's t-tests. For all statistical testing α = 0.05 was used. Color parameters (ΔE00) were calculated for every experimental composite using the CIEDE2000 color differences. Perceptibility threshold (PT), acceptability threshold (AT) and translucency differences (ΔTP) were used to compare experimental composites in both filler fraction within every resin and every resin within each filler fraction.

Results:

The statistical analysis revealed a 3-way interaction (P < 0.0001) between base monomer, filler and direction factors. For the translucency parameter, when comparing filler fraction within base monomers, there were statistically significant differences between the filler fraction within all base monomers. The analysis of color differences (ΔE00) of base monomers within filler fraction revealed that the comparison between experimental composites where beyond the acceptability threshold. The comparison of the differences in translucency parameter (ΔTP) of base monomers within filler fraction were beyond the perceptibility threshold, except between base monomers UT and FT.

Thus, different base monomer and filler fraction combination influences the optical characteristics of experimental composites such as: light transmission, translucency, and color appearance.

Reference:

Optical characteristics of experimental dental composite resin materials by Diana Leyva del Rio et al. published in the Journal of Dentistry.

https://www.sciencedirect.com/science/article/abs/pii/S0300571222000069

Keywords:

Diana Leyva del Rio, William Michael Johnston, Optical characteristics, Optical characteristics and dental composite resin materials, dental composite resin materials, Journal of Dentistry, Optical characteristics, Translucency, Experimental composites, Filler fraction