Written by Joyce Smith, Staff Writer. Xylitol gum, when chewed four times a day, 10 minutes each time, for a period of 21 days significantly reduced the salivary Mutans Streptococci counts compared to herbal and placebo chewing gums.

dental healthThe high prevalence of dental caries in India (60-80% of children) may be due to excessive sugar consumption 1. There is a direct relationship between tooth decay and the presence of a bacteria called Streptococcus mutans 2 that thrives in an acidic, low pH environment; therefore, steps that prevent tooth decay should include reducing acid pH in the mouth to promote an alkaline saliva. Chewing gum stimulates saliva production, elevates the pH of plaque, making it more alkaline; therefore, increasing its acid buffering capacity 3. Stimulated saliva is also supersaturated with minerals that promote the remineralization of tooth enamel 4. While chewing gum sweetened with sugar may contribute to tooth decay, chewing gum that contains xylitol provides an anti-bacterial effect 5.

This objective of this randomized, blinded, clinical study 6 was to assess and compare the salivary Mutans Streptococci counts before chewing gum (pretest) and 21 days after chewing gum (post-test). Seventy-two high school children, with at least one cavity each, and from 3 schools in Davangere city, India, were assigned to one of three groups: Xylitol, Orbital White (an herbal gum), or a placebo chewing gum and instructed to chew one pellet for 10 minutes after breakfast, lunch, evening snacks, and dinner for 21 days.

When comparing pretest to post-test, there was a statistically significant reduction in salivary Mutans Streptococci colony forming units at the end of 21 days in the group that chewed 100% xylitol sweetened gum (P < 0.01). While there was also a reduction in the colony counts of the groups that chewed herbal and placebo gums, it was not significant.

Comparisons between the three sub groups showed a statistically significant difference in mean Mutans Streptococci counts between xylitol and herbal gums (P < 0.05) and xylitol and placebo gums (P < 0.05) at the end of 21 days. When mean reduction between groups was compared, the difference was statistically significant only between xylitol and herbal gums (P < 0.05).

The researchers suggest that the lowering effect of xylitol chewing gum on Mutans Streptococci counts may be due to the fact that Xylitol, unlike sucrose, is not fermented by cariogenic plaque bacteria and therefore does not lower the pH of plaque 7. Since the plaque pH does not decrease, enamel demineralization is prevented, and plaque bacteria do not proliferate.

In this study, the placebo chewing gum group also had a reduction in salivary Mutans Streptococci counts compared to baseline even though the difference was not significant. Researchers suggest this may be due to the texture of the gum base which made the gum harder to chew, thus causing an increase in salivation. Nonetheless, 100% Xylitol sweetened chewing gum when chewed four times a day for 10 minutes each time for a period 21 days can significantly reduce the salivary S. mutans counts, which may be beneficial in controlling dental caries among those at high risk for tooth decay.

Source: Chavan, Sangeeta, Nagesh Lakashminarayan, and Umesh Kemparaj. “Effect of chewing xylitol containing and herbal chewing gums on salivary mutans streptococcus count among school children.” International journal of preventive medicine 6 (2015).

© 2015 Chavan Sunder the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Click here to read the full text study.

Posted January 29, 2018.

Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from  the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.


  1. Loesche WJ. Role of Streptococcus mutans in human dental decay. Microbiological reviews. 1986;50(4):353.
  2. Kingman A, Little W, Gomez I, et al. Salivary levels of Streptococcus mutans and lactobacilli and dental caries experiences in a US adolescent population. Community dentistry and oral epidemiology. 1988;16(2):98-103.
  3. Imfeld T. Chewing gum—facts and fiction: a review of gum-chewing and oral health. Critical reviews in oral biology & medicine. 1999;10(3):405-419.
  4. Ly KA, Milgrom P, Rothen M. The potential of dental-protective chewing gum in oral health interventions. The Journal of the American Dental Association. 2008;139(5):553-563.
  5. Van Loveren C. Sugar alcohols: what is the evidence for caries-preventive and caries-therapeutic effects? Caries research. 2004;38(3):286-293.
  6. Chavan S, Lakashminarayan N, Kemparaj U. Effect of chewing xylitol containing and herbal chewing gums on salivary mutans streptococcus count among school children. International journal of preventive medicine. 2015;6.
  7. Burt BA. The use of sorbitol-and xylitol-sweetened chewing gum in caries control. The Journal of the American Dental Association. 2006;137(2):190-196.