Zinc in primary teeth from children in Norway

Area of Science:

• Environmental Health
• Pediatric Dentistry
• Analytical Chemistry

Background:

• Human primary teeth serve as valuable biomarkers for assessing exposure to environmental heavy metals.
• Previous studies in Norway utilized primary teeth to monitor metal exposure, establishing baseline data.

Purpose of the Study:

• To determine zinc concentrations in primary teeth collected across Norway between 1990-1994.
• To compare current zinc levels with historical data and investigate correlations with environmental factors.
• To assess the adequacy of zinc intake in children based on tooth zinc concentrations.

Main Methods:

• Collection of 2747 primary teeth from dentists across all 19 Norwegian counties (1990-1994).
• Analysis of zinc concentration in ground tooth powder samples using flame atomic absorption spectrophotometry.
• Statistical analysis to compare current and historical data, assess geographic variations, and explore correlations with environmental and biological factors.

Main Results:

• The overall geometrical mean zinc concentration was 144.5 µg/g, a 5.2% increase from the 1970s, but geographic variations between counties decreased.
• No significant correlation was found between tooth zinc concentration and environmental data (drinking water, industrial discharge, population density).
• Zinc concentrations varied significantly with caries status, tooth type, and root length; few samples indicated insufficient zinc intake.

Conclusions:

• Most Norwegian children likely have sufficient zinc intake, as indicated by tooth zinc levels.
• Environmental factors do not appear to be the primary drivers of tooth zinc concentrations in this population.
• Potential contamination from dental restorations may explain some unusually high zinc values.