Selected Section: Projects of Special Interest
Milkfluoridation - Background
This presentation is based on references 1-6, see end of this page.
The beneficial effects of milk on the physical status and teeth of children
were described in the early 1930's.(4) The Swiss paediatrician Ziegler in
1953 first proposed the use of fluoridated milk as a possible dental caries
prevention medium in Winterthur where caries was highly prevalent (6). Since
then the caries-inhibiting characteristics of fluoridated milk have been
investigated in the view to using this milk in community based caries prevention
programmes. In fact, such milk fluoridation demonstration schemes already
exist in countries like Britain, Chile, China and Russia.
Planning a milk fluoridation programme
There are a number of points which have to be considered when deciding whether milk fluoridation is necessary for any given community (2).
1. Dental health status:
The oral health status within the community, especially that of the children,
must be determined properly. If the DMFT among the children is moderate
to very high, then there is a clear indication for caries preventive programmes.
2. Other fluoride sources:
The levels of fluoride in the drinking water of the community and whether
fluoride tooth pastes are being used should be considered before fluoride
dose to be delivered in the milk is estimated.
3. Urine analysis:
When a decision has been taken to implement a milk fluoridation scheme,
urinary fluoride monitoring procedure, now recognized as mandatory with
respect to safety and compliance of the programme, must be made available.
4. Milk distribution:
Fluoridated milk distribution to children is best done through an established
or existing system, like school milk or milk for kindergartens and nursery
schools. Persons at schools who would supervise milk distribution and consumption
should be identified.
Fluoridating the milk
Fluoridated milk can be produced in many different forms such as the liquid
(pasteurized, sterilized and UHT) and the powder, each may be mixed with
the choice of the different fluorides available. Sodium fluoride is by far
the commonly used agent for large scale production of fluoridated milk,
currently being used in Bulgaria, China, Russia and Britain. The other agents
are calcium fluoride, disodium monofluorophosphate (used in Chile) and disodium
silicofluoride. Except in Chile where the fluoridated milk was in powder
form, the rest of the schemes mentioned used liquid milk.
To calculate the fluoride concentration, it is necessary to consider the
volume of fluoridated milk consumed daily by each child. In Britain a child
received 189 ml of milk and in China each child got 250 ml milk. In Bulgaria,
200 ml is consumed daily and the fluoride requirement is 1 mg per day ,
the concentration of fluoride in milk is set at 5 ppm.
Manufacture of fluoridated milk using sodium fluoride
Fluoridating milk involves the addition of a fluoride to milk in appropriate
quantity, that the resulting product has the required fluoride concentration.
Sodium fluoride is generally added to milk in the form of a concentrated
aqueous solution using a fixed volume ratio to obtain the required product.
Usually one litre of the concentration of aqueous solution of sodium fluoride
is added to 1000 litres of milk. In this way the water added to the milk
is small (0.1%). Fluoridated milk is produced with different concentrations
of fluorides but a typical value may be 5 ppm F.
Sodium fluoride may be added pre or post pasteurization for pasteurized
milk. It is best that the solution of sodium fluoride is sterilized at the
time of manufacture and maintained sterile. Sterilization is achieved by
autoclaving at 121 C for 15 min. In the preparation of fluoridated UHT and
sterilized milk the fluoride solution is added before the heat treatment
of the milk. Fluoridated powdered milk is made by fluoridating the liquid
milk first to get a homogeneous product and then the water is removed in
stages to create the powder. All of the products have been shown to have
a relatively high fluoride availabilities remaining throughout their complete
shelf-lives.(2) .
Milk fluoridation programmes - Field experiences.
Scotland:
In this scheme fluoridated milk was distributed to 41/2-51/2 year olds.
The sodium fluoride solution was prepared in 300 ml sterile containers,
contents of one such container being added to 5 gallons of milk daily, giving
a final concentration of 7 ppm F per 200 ml test pack.(5).
Hungary:
Each child consumed 200 ml milk daily, 0.4 mg F was added to this volume
for the kindergarten children and 0.75 mg F for primary school children.(1).
This solution was prepared in advance by the pharmacy of the University
of Medicine, Budapest. There after trained personnel added each fluoride
dose into the correct amount of milk and stirred thoroughly for at least
10 min, after which it was drunk within 30 min (fluoridated fresh milk has
to consumed within 30 min).
Bulgaria:
A dairy in the town produced fluoridated milk by simply adding the appropriate
quantity of sodium fluoride to fresh milk prior to it's packaging into plastic
containers. In this scheme a child received 200 ml of milk containing 5
ppm F as sodium fluoride.(3)
Legislation
Based on experience gained in Bulgaria, Chile, Russia and Britain, legislation
related guidelines have been identified and may be of assistance for any
who may wish to establish a new community based milk fluoridation programme
(2).
Conclusions
Fluoridated milk seem to keep a permanently low level of ionized fluoride
within the oral cavity promoting remineralization. It is likely that this
topical mechanism contributes to the caries-preventive effect of fluoridated
milk. However there are still a series of unanswered questions, and additional studies should be performed to determine (2),
the age at which it is best to start drinking fluoridated milk
for how many years it should continue
the frequency of consumption
optimum fluoride concentration to be added
anti-caries effect of milk and it's products
***
References
1. Bánóczy J et al. (1985) Effect of fluoridated milk on caries:
5-year results. Journal of the Royal Society of Health, 105: 99-103.
2. Milk fluoridation for the prevention of dental caries (1996) World Health
Organization and Borrow Dental Milk Foundation, Geneva.
3. Pakhomov GN et al. (1995) Dental caries-reducing effects of a milk fluoridation
project in Bulgaria. Journal of Public Health Dentistry, 55: 234-237 .
4. Roberts LJ et al. (1931) Effect of a milk supplement on the physical
status of institutional children. American Journal of Diseases of Children,
56: 805-823.
5. Stephen KW et al. (1984) Five-year double-blind fluoridated milk study
in Scotland. Community Dentistry and Oral Epidemiology, 12: 223-229.
6. Ziegler E (1956) [ The fluoridation of milk ] Bulletin der Schweizerischen
Akademie der Medizinischen Wissenschaften, 12: 466- 480.
