Evidence Linking Sugar and Dental Caries in Humans

Adabelle Ng



Introduction
Dietary sucrose is broken down into its simple sugars glucose and fructose by extracellular bacterial invertases in the oral cavity. The simple sugars serve two purposes – to act as substrates for plaque microorganisms and to form a structural matrix of dental plaque. (Anderson, Curzon, Van Loveren, Tatsi, & Duggal, 2009, p.42)

Dental caries are a result of acid demineralizing the enamel and dentin layers of teeth. An increase in the proportions of acidogenic and acid tolerant bacteria, especially Streptococci mutans, is linked to caries incidence. This is due to the ability of the bacteria to rapidly metabolise dietary sugars to acid, thus reducing pH and making the tooth more susceptible to demineralization. (Sheiham, 2000) Whether or not the initial demineralization results in detectable caries or gets remineralized depends on a variety of factors – frequency and amount of further sugar consumption being one of the few. (Burt & Pai, 2001, p.1017)

Our diet plays a huge role in the number of dental caries observed in individuals. It was observed that in countries which had a traditional diet low in sugars although high in starch, the incidence of dental caries was very low. When such countries adopted the more "westernized" diet which is high in sugar, there was a significant increase in the number of dental caries experienced by the population.

Aside from human studies, animal studies were also carried out to determine the relationship between sugars and dental caries. However, due to the differences in animal and human teeth, the result of such studies are not always transferable to human cases.

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Studies have been done over the years to provide evidence of the relationship between sugar and dental caries.



With changes in diet:

(a) Hopewood House Study (Anderson, Curzon, Van Loveren, Tatsi, & Duggal, 2009, p.42)

Main conclusion: The percentage of caries free mouths for children related to the use of a lacto-vegetarian diet was higher when compared to that of living children who had a higher use of sucrose.

(b) Tristan da Cunha Report (Anderson, Curzon, Van Loveren, Tatsi, & Duggal, 2009, p.2)

Main conclusion: Diet was modernized when people were evacuated to England from an island after a volcano eruption. Hence, an increase in dietary consumption of sugars resulted in a rapid rise in caries experience.


With changes in intake frequency:

(a) Vipeholm Study (Lingström, et al., 2003, p.331; Anderson, Curzon, Van Loveren, Tatsi, & Duggal, 2009, p.42)


Main conclusion: Various changes in carbohydrate intake related to dental caries incidence – the more frequent the intake, the greater the caries incidence; sugars taken between meals have a greater cariogenicity than that taken during meals. [Carried out at an institution for the mentally retarded in Sweden]

(b) A recent study in the USA showed that there is a positive correlation between cumulative caries scores and the frequency of mealtime and between-meal use of carbonated beverages. (Tahmassebi, Duggal, Malik-Kotru, & Curzon, 2004, p.3)


With volume of sugar intake:

(a) In countries where the annual per person sugar consumption was below 20kg, high proportions of adults were caries-free. When it is above 20kg, the percentage with caries was over 98%. (Sheiham, 2001)

(b) During World Wars I and II, there was also a significant drop in the number of dental caries observed in numerous countries. This was a result of a reduction in the availability of sugar, as the government imposed sugar rationing. (Mellanby, Martin, & Barnes, 1958)


Non-cariogenic sugars:

Sugar substitutes, including polyol sweeteners and artificial sweeteners, are widely used these days. Studies have shown that such sugar substitutes are not metabolized by oral bacteria to produce acids, hence they do not induce caries production. (Ly, Milgrom, & Rothen, 2008, p.554)

Xylitol and calcium lactate have been shown to enhance remineralization of enamel surfaces. (Ly, Milgrom, & Rothen 2008, p.554)

(a) Turku study (Scheinin, Makinen, & Ylitalo, 1976)

Carried out on adults in Finland in the 1970s, the Turku study served as a controlled dietary intervention study where almost all the sucrose in the diet was substituted by the non-cariogenic sugar Xylitol. An 85% reduction in dental caries was observed over a period of 2 years.

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References

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. Lingstrom, P., Holm, A. K., Mejare, I., Twetman, S., Soder, B., Norlund, A., et al. (2003). Dietary factors in the prevention of dental caries: a systematic review. Acta Odontol Scand, 61(6), 331-340

4. Ly, K. A., Milgrom, P., & Rothen, M. (2008). The potential of dental-protective chewing gum in oral health interventions. J Am Dent Assoc, 139(5), 553-563.

5. Mellanby, M., Martin, W. J., & Barnes, D. (1958). Teeth of 5-year-old London school-children (1957) with a comparison of the results obtained from 1929 to 1957. Br Med J, 2(5110), 1441-1443.

6. Scheinin, A., Makinen, K. K., & Ylitalo, K. (1976). Turku sugar studies. V. Final report on the effect of sucrose, fructose and xylitol diets on the caries incidence in man. Acta Odontol Scand, 34(4), 179-216.

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

8. Tahmassebi, J. F., Duggal, M. S., Malik-Kotru, G., & Curzon, M. E. (2006). Soft drinks and dental health: a review of the current literature. J Dent, 34(1), 2-11.




Links
Diet and Dental Caries | Types of Sugar | Cariogenicity of Other Foods | Evidence Linking Sugar and Dental Caries in Humans | Influence of Consumption Pattern | Malnutrition and Dental Caries | Influence of Fluoride on the Sugar/Caries Relationship | Protective Factors in Foods | Non-Sugar Sweeteners | Dietary Control and Dental Caries | Summary