The impact of zirconium dioxide nanoparticles on the color stability of artificially aged heat-polymerized maxillofacial silicone elastomer

The limited service life of craniofacial prostheses due to degradation and color instability is a significant challenge. This in vitro study aimed to determine how zirconium dioxide (ZrO 2 ) nanoparticles affect the color stability of M511 heat temperature vulcanizing (HTV) maxillofacial silicone elastomers after artificial aging. ZrO 2 nanoparticles were added at concentrations of 1, 2, and 3 wt% to M511 HTV silicone elastomer. Two intrinsic silicone pigments were used (red and mocha). Silicone with pigment and without ZrO 2 nanoparticles were used as the control. Eighty disk-shaped specimens were fabricated and divided into eight experimental groups, each containing ten specimens (n = 10). All specimens were subjected to artificial aging, and color changes were recorded at 252, 504, and 1008 h intervals. The L*a *b * values were measured using a colorimeter and the CIE-Lab system. To interpret the recorded color differences, a 50:50 percent perceptibility threshold (ΔE* = 1.1) and acceptability threshold (ΔE* = 3.0) were implemented. A one-way analysis of variance and Tukey's post hoc test at a significance level of 0.05 were used for the statistical analysis. We found that every evaluated specimen group exhibited a chromatic change (ΔE* > 0). The ΔE* values for the mocha pigments with and without ZrO 2 nanoparticles were below the perceptible threshold (1.1 units). The ΔE* values of the red pigment with and without ZrO 2 nanoparticles were significantly higher than the acceptable threshold (P < 0.000). According to the findings of this in vitro study, all the specimens underwent color changes (ΔE* > 0). The red pigment exhibited highly significant chromatic alterations. In contrast, mocha pigments with and without ZrO 2 nanoparticles exhibited the least color change and were below the perceptible threshold. ZrO 2 nanoparticles provided important protection and showed a reduction in color change.