Topical Fluorides II
Dental caries levels were observed to decrease worldwide since the introduction of fluoridated toothpastes in the early 1970s.
- Abrasives (20–50%): calcium phosphate, calcium carbonate, alumina or hydrated silica (to remove food debris, plaque and to scour off biofilm).
- Water (20–40%).
- Humectants (20–35%): sorbitol and/or glycerol to reduce loss of moisture and to ensure it becomes a manageable paste.
- Surfactants (0.5–2.0%): sodium lauryl sulphate to provide foaming and detergent properties.
- Flavouring and sweeteners (0–2.0%): usually mint to give a pleasant taste.
- Active ingredients (0–2.0%): therapeutic agents such as fluoride, triclosan, potassium nitrate and potassium citrate.
- Gels and binding agents (0.5–2.0%): carboxymethyl and hydroxyethyl cellulose to control the consistency of the paste.
- Colouring and preservatives (0–0.5%).
These exist as sodium fluoride (NaF), sodium monofluorophosphate (NaMFP), stannous fluoride (SnF) and amine fluoride (AmF). The ionic concentrations of fluoride in dentifrices with different fluoride agents are:
Levels of Fluoride in Toothpastes
The most common adult formulations contain 1000 ppm F although the EU directive allows up to 1500 ppm F for over-the-counter sales of dentifrices. Low-fluoride toothpastes containing 500–750 ppm F (and less) are available for children and were introduced to avoid the risk of fluorosis and due to the decreasing caries levels that were being observed. The evidence for the caries preventive efficacy of these low-fluoride pastes is very weak and therefore should not be recommended for caries-risk children. They should be recommended for caries-free children under the age of 6 years especially if they are residing in a water fluoridated area to avoid the risk of ingestion of toothpaste and hence dental fluorosis. Prescription only fluoride toothpastes containing 2800 ppm F and 5000 ppm F are available for high caries-risk individuals.
Dose Response of Fluoride Concentration
For each 500 ppm F increase in fluoride concentration in toothpastes there is a further reduction in caries levels. The additional use of fluoride alongside fluoridated toothpaste has been shown to lead to additional caries reductions. For young children the benefits of caries reduction must be considered alongside the risk of dental fluorosis when increasing the concentration of fluoride in toothpastes.