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Clinical Studies

Mother and child study

The aim of the study was to explore whether mothers' habitual xylitol consumption could prevent the mother-child transmission of Streptococcus mutans, and how the result would be reflected in caries occurrence in the children.

Altogether 195 pregnant women with high salivary mutans streptococci levels were invited to the study. In the xylitol group, the mothers chewed xylitol chewing gum approximately four times a day for about two years. The use of the xylitol gum was started before the first primary teeth erupted to ensure that the "xylitol-effect" on the oral flora was established.

In the two control groups, the mothers received either fluoride or chlorhexidine varnish applications, 6, 12 and 18 months after delivery. All interventions discontinued when the child was two years old. Both saliva and plaque samples were collected from the mothers and their children during the study. The S. mutans levels of the samples were determined both using plate culturing and a strip test.

169 mother-child pairs, with the child at the age of two, participated in the study. In the xylitol group only 10 % of the children became colonized with mutans streptococci  bacteria, even though the salivary bacteria levels of their mothers were not reduced during the xylitol consumption period. Xylitol did thus not reduce the children's colonization by reducing that of their mothers, but rather by affecting the transmission properties of the mutans streptococci.

In the Xylitol group, only 10 % of the children became colonized with Streptococcus mutans. The corresponding results in the control groups were: In the F-varnish group, the colonization percentage was 49% and, in the CHX group, 29 %. At the age of 5 years, the children whose mothers had consumed xylitol chewing gum in the original study had significantly less dental caries (71–74% decayed, missing or filled teeth) than the children in the other two groups (Isokangas et al. 2000). Interestingly, although the children of mother’s in the chlorhexidine group exhibited reduced colonization by Mutans Streptococci after two years, this did not translate into a reduction in caries incidence after five years. This further supports the theory that xylitol does not exert an antibacterial effect on the oral bacteria, but rather a “modulating” effect on the oral flora as a whole, resulting in a shift towards a less virulent/cariogenic flora.

There was even a further follow up whereby the effects of xylitol were evaluated in children at the age of 10 (10 year follow up). It was observed that the primary teeth of the children belonging to the xylitol group were maintained completely cavity free. This has been attributed to the fact that xylitol has influenced the bacterial composition of the bacterial strain transmitted from mother to child. In addition, children from high risk mothers who used 100% xylitol containing chewing gum during the course of the study, when under the age of 2, appeared with their first cavities at the age of 8. These children also indicated 40% less caries when compared to the rest of the groups. In particular, the teeth of the children with mutans streptococci colonization had developed caries as early as the age of 5. Perhaps the most remarkable finding of this study is that this impressive reduction in caries was achieved solely through the treatment of the mothers, as the children received no treatment during this period. In addition, the follow up 10 year study is a proof of the long lasting effects of xylitol which are beneficial in this unique way.


Söderling E, Isokangas P, Pienihäkkinen K, Tenovuo J. Influence of Maternal Xylitol Consumption on Acquisition of Mutans Streptococci by Infants. J Dent Res, 79: 882-887, 2000.

Isokangas P, Söderling E, Pienihäkkinen K, Alanen P. Occurrence of Dental Decay in Children after Maternal Consumption of Xylitol Chewing Gum, a Follow-up from 0 to 5 Years of Age. J Dent Res, 79 (11): 1885-1889, 2000.

Laitala MLDental Health in Primary Teeth after Prevention of Mother-Child Transmission of Mutans Streptococci. A Historical Cohort Study on Restorative Visits and Maternal Prevention Costs. Dissertation at the University of Turku 24 September 2010.

Six year study in Estonia

The study was a school based program that controlled consumption of the test products, and limited them to school days only (no consumption at weekends or during school vacations). Despite this, all three xylitol groups exhibited significant reductions in caries incidence, indicating that xylitol offers long term caries protection, that continues even when consumption is not continuos. Such a finding suggests that xylitol could form the basis of an effective school based caries prevention program. A daily dose of xylitol (5g per day) was instructed to be consumed by children - compared to a number of the previous clinical trials into the effect of xylitol against tooth decay, this was a relatively low dose of xylitol.

This was the first clinical study that evaluated different delivery vehicles side by side. The study evaluated three xylitol containing products – two different candies and a chewing gum. All of the xylitol study groups resulted in a 35% to 60% reduction in caries incidence after 3 years. This study clearly shows that xylitol continues to have a significant effect in a vehicle where the physical action of chewing is far less pronounced. It can therefore be concluded that it is the action of xylitol (even at a dose of only 5g per day), and not just the mechanism of consuming a sugar free chewing gum, that is responsible for this dramatic reduction in caries incidence.

After two years' use, caries reduction in all xylitol groups was approximately 50% compared with the control group. In the study, xylitol was used only on schooldays, approximately 200 days a year. Despite the three-month summer holiday, the prevention effect achieved was as good as in previous xylitol studies, where xylitol for the most part had been used on a daily basis. The study proved that when xylitol is used regularly for a sufficient period, even a three-month break did not reduce its effect.


Alanen P, Isokangas P, Gutmann K: Xylitol candies in caries prevention: results of a field study in Estonian children. Community Dent Oral Epidemiol 2000; 28: 218-24.

The Belize Xylitol chewing gum trials

Nine groups were studied, comprising 1277 subjects. One control group was provided with no gum at all; four xylitol gum-chewing groups received either pellet- or stick-shaped gum for either 3 or 5 supervised sessions/school day (with a range of xylitol consumption from 4.3 to 9.0g/day);; one group used sorbitol pellet gum for 5 sessions/school day (9.0g/day); two groups used either xylitol or sorbitol pellet gums 5 times/school day (with a total polyol consumption from 8.0 to 9.7g/day); one group used sucrose gum 5 times/school day (9.0g/day).

Compared with the no-gum group, sucrose gum usage resulted in a marginal increase in caries rate (relative caries risk 1.20), while sorbitol gum reduced the caries rate (relative caries risk 0.74). The four xylitol gums were most effective in reducing caries rates (relative caries risks from 0.48 to 0.27). The most effective product was a 100% xylitol pellet gum (relative caries risk 0.27). The xylitol–sorbitol combinations were less effective than xylitol, but reduced the caries rates significantly compared to the no-gum or sorbitol-gum groups. These results suggest that the regular usage of polyol-based chewing gum reduces caries rates in young subjects, with xylitol gums being most effective. The Belize trials represent the most comprehensive study to date of the caries-preventive properties of sugar-free chewing gum, and in particular xylitol-sweetened chewing gum.


Isokangas,P., Alanen,P. Tiekso,J., Mäkinen K.K. Xylitol chewing gum in caries prevention: a field stydy in children. JADA 1988 117:315-320.

Hujoel P.P., Isokangas, P., Tiekso, J., Davis S., Lamont R.J., DeRouen T.A., Mäkinen K.K. A re-analysis of caries onset rates in a preventive trial using Poisson regression models. Journal of Dental Research 1994 73:573-579.

Pape H.R.jr., Mäkinen K.K. Verification and maintenance of dental explorer sharpness. Oper. Dent. 1994 19:221-223.

Hujoel P.P., Mäkinen K.K., Bennet C.A., Isokangas P., Isotupa K.P. Pape H.R. jr., Do caries explorers transmit infection within persons? An evaluation of second molar caries onsets. Caries res. 1995 29:461-466.

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