Influence of Fluoride on the Sugar/Caries Relationship

Mok Li Qian


The expanding prevalence of fluoride exposure in industrialized countries has proven to alter the linear sugar-caries relationship that was once common in the pre-fluoride era. Of course, the rise in sugar consumption still increases the occurrence of dental caries, but with more widespread exposure to fluorides, the influence of sugars has vastly weakened.


Statistical Observations

Systemic reviews conducted by Burt & Pai (2001) showed that fluoride exposure has greatly depressed the upward relationship between sugar consumption and caries. Furthermore, fluoride use proves to curb the ubiquity of caries, especially in young children. Topical fluoride present toothpaste, rinses or varnishes appears to reduce caries in children by 20 to 40%.

A study (Künzel, 1982) was conducted on 200,000 Germans in 1979, where the sugar consumption of rose from 19 kg in 1950, to 27 kg in 1955 and 39 kg in 1979, the DMFT[1] of children between 11 to 15 years of age rose from 4.2 to 5.5; and then declined to 3.4 with partial water fluoridation.

However, this does not prove that fluoridation has eradicated the prevalence of caries in industrialized countries. A study conducted in Ireland with a population age group of 35 to 44 years revealed a mean DMFT of 18.9. (O'Mullane & Whelton, 1992) Under WHO dental care guidelines, a DMFT of 14.0 and above is regarded as high for this age group. (Moynihan, 2002)


The Role of Fluoride in Protecting the Teeth

Recommended total dietary fluoride intake
Table 1. Recommended total dietary fluoride intake; table taken from

Fluoride is the key in enhancing the resistance of the teeth against acid attacks and its interaction with sugars in plaque. Fluoride binds to the enamel lattices by converting apatite to fluroapatite, a compound that is more stable and less soluble than hydroxyapatite. Hence, the mineralization of the enamel in the presence of fluoride boosts its resistance against subsequent demineralizations during food consumptions. In addition, fluoride alters the ecology of dental plaque and decreases the amount of acid produced during consumption. For more detailed elaborations on the effects of fluoride on the teeth, please refer to Caries Control & Treatment.

As a result, in industrialized countries where fluoride exposure is widespread through the usage of toothpastes as well as water and salt fluoridation, people’s tolerance to cariogenic diets are markedly raised – and this makes the sugar-caries relationship more difficult to detect.


[1] The count of the number of teeth in a person’s mouth that are decayed, filled or extracted.



1. Anderson, C. A., Curzon, M. E., Van Loveren, C., Tatsi, C., & Duggal, M. S. (2009). Sucrose and dental caries: a review of the evidence. Obes Rev, 10 Suppl 1, 41-54.

2. Burt, B. A., & Pai, S. (2001). Sugar consumption and caries risk: a systematic review. J Dent Educ, 65(10), 1017-1023.

3. Kunzel, W. (1982). [Relation of caries prevalence to the fluoride content of drinking water and annual sugar consumption]. Zahn Mund Kieferheilkd Zentralbl, 70(6), 584-590.

4. Moynihan, P. (2002). Annex 6: the scientific basis for diet, nutrition, and the prevention of dental diseases, Background paper for the Joint FAO/WHO Expert Consultation on diet, nutrition, and the prevention of chronic diseases. Geneva: World Health Organization. .

5. O'Mullane, D., & Whelton, H. (1992). Oral health of Irish adults 1989-1990. Dublin: Government Publications.

6. Sheiham, A. (2001). Dietary effects on dental diseases. Public Health Nutr, 4(2B), 569-591.

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