According to Nadimi et al. 2011 the health claim “tooth friendly” for chewing gums containing xylitol and other claims, such as “sugar-free” may create a false health-perception among consumers that all sugar-free products are safe on teeth. 
Xylitol, a polyol, has been approved by the US Food and Drug Administration and by the European Union as non-cariogenic food additive, which reduces tooth decay when used to replace sugar. Nadimi points to the fact that the presence of acidic flavourings and preservatives in sugar-free products may have adverse dental health effects, such as dental erosion. The authors reassure that polyol-based sugar-free products may decrease dental caries incidence but, otherwise, acidic additives may increase dental erosion and health claims may induce false dental safety perception of the consumer.
Studies found sorbitol-sweetened gum to have low cariogenicity when used not more the three times /day and Xylitol-sweetened gum was noncariogenic compared with sugar sweetened products. Burton 2006 says these studies suggest that regular use of xylitol-sweetened gum may prevent caries, and may become a public-health preventive measure. 
Xylitol can decrease mutans streptococci levels in plaque and saliva and can reduce dental caries in young children, mothers, and in children via their mothers.The use of xylitol to reduce caries is being supported by these studies. Ly, Milgrom and Rothen 2006 urge professional associations to push for clear recommendations of efficacious dose and frequency of xylitol use and for clear labelling of xylitol content in products. 
According to Seki 2011 xylitol gum is effective in avoiding increased plaque mutans streptococci in young children. 
 Nadimi H, Wesamaa H, Janket SJ, Bollu P, Meurman JH: Are sugar-free confections really beneficial for dental health? Br Dent J. 2011 Oct 7;211(7):E15. doi: 10.1038/sj.bdj.2011.823.
 Burt BA: The use of sorbitol- and xylitol-sweetened chewing gum in caries control. J Am Dent Assoc. 2006 Feb;137(2):190-6.
 Ly KA, Milgrom P, Rothen M: Xylitol, sweeteners, and dental caries. Pediatr Dent. 2006 Mar-Apr;28(2):154-63; discussion 192-8.
 Seki M, Karakama F, Kawato T, Tanaka H, Saeki Y, Yamashita Y: Effect of xylitol gum on the level of oral mutans streptococci of preschoolers: block-randomised trial.Int Dent J. 2011 Oct;61(5):274-80. doi: 10.1111/j.1875-595X.2011.00073.x.