Systemic Fluoride Bioavailability From Toothpastes Containing Calcium Carbonate or Silica as Abrasives

Systemic Fluoride Bioavailability From Toothpastes Containing Calcium Carbonate or Silica as Abrasives

The risk of dental fluorosis development is related to the systemic exposure to fluoride during enamel formation. Currently, diet and fluoride toothpastes are the main sources of fluoride to children at the age-risk for fluorosis development. However, when estimating the risk of fluorosis from toothpaste inadvertently ingested, it has not been considered the systemic fluoride bioavailability. Since some toothpaste formulations may contain part of fluoride as insoluble salts, the hypothesis behind this study is that only soluble fluoride in toothpastes would be absorbed when they are inadvertently ingested. To test that, adult volunteers will ingest a standardized dose of total fluoride from commercially available toothpastes, which present different concentrations of soluble fluoride. Fluoride systemic bioavailability will be assessed by the release of fluoride in saliva up to 3 hours after ingestion (as an indicator of blood fluoride) and by urinary fluoride excretion.

Ingestion of 31.9 mg of a fresh toothpaste containing 1450 ppm total fluoride per kg body weight, diluted in 30 mL of purified water, to provide a total intake of 49.5 ug of fluoride/kg body weight.

Ingestion of 49.5 mg of a fresh toothpaste containing 1100 ppm total fluoride per kg body weight, diluted in 30 mL of purified water, to provide a total intake of 49.5 ug of fluoride/kg body weight.

Ingestion of 49.5 mg of a toothpaste containing 1100 ppm total fluoride per kg body weight, diluted in 30 mL of purified water, to provide a total intake of 49.5 ug of fluoride/kg body weight. The toothpaste had been previously aged to simulate one year storage at room temperature.

Ingestion of 31.9 mg of a toothpaste containing 1450 ppm total fluoride per kg body weight, diluted in 30 mL of purified water, to provide a total intake of 49.5 ug of fluoride/kg body weight. The toothpaste had been previously aged to simulate one year storage at room temperature.

Saliva will be collected before and up to 3 hours after ingestion of the toothpastes or negative control. Collections (during 3 min) will be made at 0 (immediately before ingestion), 15, 30, 45, 60, 120 and 180 min after ingestion.

Saliva collected up to 3 hours after the ingestion of toothpastes or negative control will be analyzed for fluoride concentration and the maximum concentration during this period will be recorded.

Urine will be collected for the 24 hours preceeding the ingestion of the toothpastes or negative control and for the 24 hours after the ingestion. The difference in the amount of fluoride excreted in 24h urine samples, after or before the treatments, will be calculated.

Inclusion Criteria: Good general health Good oral health Normal salivary flow rate Exclusion Criteria: Gastric disorders Renal disorders

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