Title: Color Stability of Heat-Polymerized Acrylic Resins with Incorporated Ag Nanoparticles
Abstract:
Some nanoparticles have been added to polymethyl methacrylate (PMMA) for antimicrobial properties; however, they can affect color stability of acrylic resin. The aim of this study was to investigate the effect of Ag Nanoparticles on color changes of heat-polymerized acrylic resins. PMMA specimens (n=10) containing different sizes (15nm, 45nm) of Ag Nanoparticles (concentration of 0.1%) were prepared, along with a control group with no Ag Nanoparticles. Fabricated specimens were stored in distilled water at 37°C for 50±2 h to simulate the oral environment. The color was evaluated according to the Commision Internationale de l’Eclairage (CIE) CIEL*a*b* color system. The comparison of L, a, b values was made at the level of significance of p<0,05 using one-way ANOVA and post hoc multiple comparisons test (Tukey HSD) were used to identify any statistical differences between groups. After addition of Ag Nanoparticles to PMMA, L * and b * values increased, and a * values decreased. The present study also found that the addition of large-sized nanoparticles (40NM) lead to higher values for L * and b *. According to the results obtained, the difference between the values of L, a, b and among the groups was found to be statistically significant (p <0,05). Delta e value was found to be 2.51 between group A and B, 1.53 between group A and control group, and 4.03 between group B and control group. Group A is clinically acceptable while group B is slightly above the clinically acceptable value. According to the results of this study, color change after addition of Ag Nanoparticles to heat-polymerized acrylic resins is not determined in group A, but determined in group B (slightly above the clinically acceptable value). The addition of Ag Nanoparticle and size of nanoparticle did not significantly affect the color stability of PMMA. Accordingly, adding a suitable concentration of Ag Nanoparticle to PMMA may used in clinical practice.
