Systemic absorption of fluoride from alginate impression material in humans.

Thirty minutes after routine alginate impressions in five adult subjects, plasma fluoride levels increased by an average of 2.6 times over control values. Urinary fluoride excretion rates increased approximately 2.9 times during the first two hours after the impressions. Average whole saliva fluoride levels at 15 minutes were over 100 times the average control concentration. When small amounts of alginate were deliberately ingested, plasma fluoride levels and urinary excretion rates increased sharply.