The use of fluoride as caries prophylactic does not pose a health risk
Caries-prophylactic use of fluoride is regarded as safe.
Aida Mulic Jon E. Dahl
Senior Scientist Managing Director
Fluoride skepticism “FluUro”. The use of fluoride as caries prophylactic does not pose a health risk, Professor Jon E. Dahl, stated at the annual convention for the Norwegian dental association. He discussed the kinetics and the general toxicity of applied fluoride. A negligible amount of fluoride is absorbed through the oral mucosa; however, about 90% of a swallowed dose is taken up in the blood and distributed. Between 30 and 50% of the absorbed fluoride is deposited in the teeth during their formation and in the bones. Fluoride that is not taken up in the hard tissues is secreted by the kidney (40-60%) or the gut (about 10%).
Acute toxicity may occur on intake of more than 5 mg of fluoride per kg body weight. (Table 1). This corresponds to such a large dose of that accidental poisoning can be ruled out. Skeletal fluorosis is a bone disease caused by excessive accumulation of fluoride in the bones. It is seen in countries where there is natural high level of fluoride in the drinking water, such as China and India, and it is not relevant for the Nordic countries. Studies from areas with water fluoridation do not provide evidence that the daily uptake of fluorides presents any health hazards.
Table 1: Examples of added amount that trigger acute toxicity reactions in children and adults
| Age | Weight | Amount toothpaste (1450 ppm F-) 75 mL | Tablets (0,5 mg) |
|---|---|---|---|
| 1 yr | 10 kg | 1/2 tube | 100 |
| 5 yrs | 20 kg | 1 tube | 200 |
| 12 yrs | 30 kg | 1,5 tubes | 300 |
| Adult | 70 kg | 3 tubes | 700 |
The “FluUro” session at the convention concluded with senior scientist Aida Mulic who discussed the recommended use of fluorides. According to Mulic, the effect of local fluoride treatment depends on concentration of fluoride, length of time of application, frequency of treatment, the pH of the fluoride product, and the presence of metal fluorides (tin or titanium) used in combination with NaF.
Table 2: Overview of available fluorid prophylactics and their concentration of F- (ppm)
| Fluorid prophylactic | F-(ppm) |
|---|---|
| Toothpaste | 1000-1500 |
| Daily fluorid rinse (0,2% NaF) | 920 |
| Duraphat® toothpaste | 5000 |
| Fluor Protector | 1000 |
| Fluorid varnish 2% NaF | 9200 |
| Duraphat® varnish with 5% NaF | 22600 |
Regarding professional treatment offered at the dental clinics, fluoride varnish (5% NaF / 2% NaF) applied at least twice a year gives caries reduction of 42-46%. Although the scientific evidence for the use of fluoride gel is limited, this treatment is recommended for a limited period for patients with severe dental caries for a limited period until the caries situation is under control.
Clinical implication: Caries prevention by daily use of fluoride containing toothpaste is documented as safe and effective.
