Effect of Different Pediatric Iron Supplements on Color Changes in Pediatric Zirconia Crowns: An In Vitro Study

Objectives This in vitro study evaluated color changes in prefabricated zirconia crowns after repeated exposure to commonly prescribed pediatric iron supplements with different chemical formulations.Materials and Methods Thirty prefabricated zirconia crowns were randomly assigned to three groups (n = 10) according to the iron formulation: ferric polymaltose, ferrous sulfate, and microencapsulated iron. To standardize iron exposure, the volume of each supplement was adjusted to deliver an equivalent dose of 40 mg elemental iron per application. Specimens were immersed daily for 2 minutes in undiluted iron solutions for 28 days using an immersion cycling protocol simulating routine pediatric syrup intake. Color measurements were performed at baseline, day 7, and day 28 using a digital spectrophotometer based on the CIE L*a*b* color system. Color differences (ΔE*) and lightness changes (ΔL*) were calculated. Data were analyzed using non-parametric statistical tests (α = 0.05).Results All iron formulations induced perceptible and clinically unacceptable color changes over time. At day 28, a statistically significant intergroup difference in ΔE* values were observed (p = 0.013). Crowns exposed to ferric polymaltose exhibited significantly lower color change values compared with those exposed to ferrous sulfate and microencapsulated iron. No significant intergroup differences were detected for ΔL*.Conclusion Repeated exposure to pediatric iron supplements resulted in measurable discoloration of prefabricated zirconia crowns in this in vitro model. The extent of staining differed according to iron formulation, with ferric polymaltose showing a lower staining tendency than the other supplements tested. Given the experimental design, these findings should be interpreted cautiously, and further clinical or in vivo studies are needed to clarify the esthetic implications of pediatric iron supplementation under oral conditions.