Mercury in biological fluids after amalgam removal

Area of Science:

• Environmental Health
• Toxicology
• Dental Materials

Background:

• Dental amalgam is a primary source of inorganic mercury (Hg) exposure in the general population.
• Understanding mercury kinetics after amalgam removal is crucial for assessing health impacts.

Purpose of the Study:

• To investigate changes in blood, plasma, and urine mercury levels after complete dental amalgam removal.
• To determine the kinetics and half-lives of mercury elimination from biological fluids post-amalgam removal.

Main Methods:

• 12 healthy subjects with an average of 18 amalgam surfaces underwent complete amalgam removal in one session.
• Frequent blood sampling and 24-hour urine collections were conducted up to 115 days post-removal.
• Plasma and urine samples were collected for up to three years in eight subjects to determine mercury half-lives.

Main Results:

• A transient increase in blood and plasma mercury concentrations was observed within 48 hours post-removal, with plasma levels peaking 32% higher than pre-removal levels.
• No significant increase in urinary mercury excretion rate was detected immediately after amalgam removal.
• Mercury levels in blood, plasma, and urine exponentially declined, reaching approximately 60% of pre-removal levels by 60 days. Median half-lives were 88 days for plasma and 46 days for urine.

Conclusions:

• Amalgam filling removal significantly impacts mercury levels in biological fluids.
• Following removal, mercury levels decrease substantially, gradually approaching levels found in individuals without a history of amalgam fillings.
• The study provides valuable data on mercury kinetics, highlighting the long-term decline of mercury after amalgam replacement.