The aim of the study was to establish whether maternal use of sugar free chewing gum, sweetened with the naturally occurring sweetener xylitol, could reduce the transmission of harmful mutans streptococci (MS) bacteria from mother to child and thereby reduce the risk of dental caries in their children. Earlier published studies have demonstrated that prevention of colonization by these bacteria in early childhood can lead to reduction of dental decay and that mothers are the primary source of infection with mutans streptococci. These bacteria are passed from mother to child through everyday contacts such as kissing, and tasting of food.
The mothers were recruited for the study during pregnancy, and were assigned to one of three study groups. The xylitol group mothers chewed xylitol chewing gum approximately four times a day from 3 to 24 months after the child was born. The mothers in the two control groups received fluoride (which does not affect MS transmission, but strengthens tooth enamel), or chlorhexidine (which is supposed to reduce MS transmission) varnish treatments at 6, 12, and 18 months post delivery. Otherwise, normal dietary and oral hygiene practices were maintained.
The study measured the occurrence of tooth decay in the children at the age of five years: dental caries (dmft - decayed, missing, filled teeth) in the xylitol group was reduced by 71 - 74% as compared with the two control groups. Thus, the study concluded that the mothers' use of xylitol chewing gum prevented tooth decay in their children by significantly reducing the transmission of mutans streptococci from mother to child in early childhood.
The results of this study suggest that intervention against MS colonization by chewing xylitol-sweetened gum may lead to better caries prevention than traditional preventive measures that concentrate on increasing the resistance of the teeth, stated Dr. Eva Soderling from The University of Turku, Finland, one of the leading researchers of the Mother-Child study.
The results of this study indicate that mothers could substantially improve their children's dental health by the simple process of chewing sugar free gum sweetened with xylitol, alongside their normal oral hygiene measures. Xylitol is a naturally occurring sweetener; manufactured from natural sources such as birch wood, which has the same sweetness as sugar as well as unique dental benefits. It is widely used in sugar free chewing gum, confectionery and oral hygiene products.
The Belize Chewing Gum Study (1989-1993)
(40 month study of permanent dentition) 
Ref: Makinen, K.K., Makinen, P.L., Pape, H.R. (Fr.), Allen, P., Bennett,
C.A., Isokangas, P.J., Isotupa, K.P.International Dental Journal 1995; 45: 93
Clinical evidence for the effectiveness of xylitol against caries
Non-cariogenic when used as a sugar substitute
In a-two year trial at the University of Turku in Finland, xylitol as clinically proven to be non-cariogenic. Group 1 ate food sweetened with sucrose, Group 2 with fructose and Group 3 with xylitol. At the end, the number of new caries registered as decayed (D), missing (M), or filled (F) tooth surfaces (i.e., the change in DMFS) was measured. While the sucrose and fructose groups had an average DMFS change of 7.2 and 3.8 respectively, virtually no new caries were seen in the xylitol group.
The Turku Sugar Study (1972-1974)
Ref: Turku Sugar Studies V. Scheinin, A., Makinen., K.K., Ylitalo, K.
Acta Ondontol. Scand. 1975; 33: 67
