Disrupted Iron Storage in Dental Fluorosis

Area of Science:

• Biomineralization
• Dental Enamel Formation
• Fluoride Toxicology

Background:

• Enamel quality depends on environmental factors, including fluoride exposure.
• Excess fluoride can alter enamel structure and gene expression.
• Iron is crucial for enamel quality.

Purpose of the Study:

• To investigate iron metabolism in dental epithelial cells and forming enamel of fluoride-exposed mice.
• To assess the relationship between fluoride exposure, iron metabolism, and enamel mechanical properties.

Main Methods:

• Perl's blue staining and secondary ion mass spectrometry imaging for iron storage.
• Quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry for protein analysis.
• Electron spin resonance, nanoindentation, scanning electron microscopy, and energy dispersive x-ray spectroscopy for enamel analysis.
• In vivo studies using Fth^+/- mice.

Main Results:

• Fluoride exposure significantly reduced iron storage in maturation-stage ameloblasts.
• Ferritin heavy chain (Fth) was identified as a primary target of fluoride.
• Fluorotic enamel showed decreased iron oxides, altered mechanical properties, and ultrastructural defects.
• Fth^+/- mice exhibited reduced iron incorporation and poor enamel quality.

Conclusions:

• Excessive fluoride exposure disrupts ameloblast iron storage, contributing to defective enamel.
• Fluoride-induced alterations in iron metabolism impact enamel's structural and mechanical integrity.
• Findings suggest potential implications of fluoride's effects on iron storage for population health.