Cariostatic effects of pediatric iron supplement formulations on streptococcus mutans–induced enamel demineralization: an in vitro study

Abstract

Background: Iron deficiency anemia (IDA) is one of the most prevalent nutritional disorders in childhood, and oral iron supplements remain the standard therapy. Experimental evidence suggests that iron may inhibit cariogenic activity; however, the in-vitro cariostatic potential of commonly prescribed pediatric iron formulations remains insufficiently characterized. Objective: To evaluate the in vitro cariostatic potential of four commercially available pediatric iron supplements on Streptococcus mutans–induced enamel demineralization using permanent human premolars. Materials and methods: A total of 120 extracted sound permanent human premolars were randomly allocated into six groups (n = 20): four iron supplement groups (Fre-in-sol, Ferotonic, Feromin, Ferose), a positive control (S. mutans + 10% sucrose), and a negative control. Artificial caries lesions were induced using S. mutans (strain 6715) with 10% sucrose under anaerobic conditions for 60 days. Enamel demineralization was assessed daily using ICDAS-II visual criteria, tactile examination, and DIAGNOdent laser fluorescence. Incidence data were analyzed using Chi-square or Fisher’s exact tests (α = 0.05), while DIAGNOdent values and time-to-onset were summarized descriptively and analyzed statistically where applicable. Results: All specimens in the positive control group developed enamel demineralization by day 12 (20/20, 100%). In contrast, Fre-in-sol (2/20, 10%), Ferotonic (3/20, 15%), and Feromin (3/20, 15%) groups showed significantly reduced demineralization incidence compared with the positive control (p < 0.001), with delayed mean onset ranging from 29 to 47 days. The Ferose group demonstrated higher demineralization (16/20, 80%) and did not differ significantly from the positive control (p = 0.053). Mean end-of-study DIAGNOdent readings were lowest for Fre-in-sol (8.4 ± 2.3), Ferotonic (9.7 ± 2.6), and Feromin (9.1 ± 2.4), highest for the positive control (38.6 ± 4.1), and intermediate for Ferose (24.9 ± 3.8). Cavitation was observed only in the positive control (20%) and Ferose (5%) groups. Conclusion: Within the limitations of this in vitro study, ferrous sulfate–based pediatric iron formulations showed greater inhibition of S. mutans–induced enamel demineralization than ferric polymaltose. These findings indicate a formulation-dependent in vitro cariostatic potential and support further investigation under clinical conditions. Clinical significance: Certain pediatric iron supplements showed in vitro cariostatic effect and could potentially provide inhibition effect for caries activity in addition to correcting anemia. However, pediatric clinical studies are required before recommendations regarding formulation selection can be made.