Color Mapping of Teeth Restored Using Dental Adhesives Loaded with Magnetic Nanoparticles

Background and Objectives: Conventional dental adhesives doped with magnetic nanoparticles (MNPs) hold the promise of preventing microleakages. However, esthetic concerns have motivated the quest for coatings capable of masking the dark color of MNPs. This study aims to quantify regional chromatic differences between teeth restored using dental adhesives with different MNP content. Materials and Methods: We prepared cavities in 42 artificial molars and 9 extracted teeth and divided them into 6 groups: Group 0 (G0), G1, and G2, comprising 14 artificial teeth each and G0e, G1e, and G2e, comprising 3 extracted teeth each. In G0 and G0e, we applied the commercial adhesive, in G1 and G1e we applied the adhesive loaded with MNPs with dual coating (SiO₂ followed by Ca(OH)₂), whereas in G2 and G2e we applied the adhesive doped with uncoated MNPs. For the statistical analysis of color differences, we employed Bland-Altman plots and the one-sample t-test. Results: G1 was similar to G0 in terms of color coordinate distribution, whereas G2 was different. Compared to G0, dental fillings from G1 had mean differences of (-0.56, 0.18, -0.07) in the CIELAB color coordinates (L*, a*, b*), respectively, whereas the mean differences between G2 and G0 were (-15.6, -3.5, -15.7). The CIEDE2000 color differences were 1.5 [1.3, 1.6] between G1 and G0 (mean [95% confidence interval]) and 17.0 [16.0, 18.0] between G2 and G0. Nevertheless, 24.4% of the point pairs compared exceeded the acceptability limit for color difference (1.8). Conclusions: Although the silica and calcium hydroxide coating is highly effective in alleviating the esthetic impact of MNP-laden dental adhesives, further research is warranted to reduce between-specimen variability.