Xylitol is a “
tooth-friendly”,
nonfermentable sugar alcohol.
[12][13] A review of the scientific literature
[14] on the efficacy of xylitol has indicated dental health benefits in
caries prevention, showing superior performance to other
polyols (polyalcohols). This is because the structure of xylitol contains a
tridentate ligand, (H-C-OH)
3 that can rearrange with polyvalent cations like Ca
++. This interaction allows for Ca
++ to be transported through the gut wall barrier and through saliva may remineralize enamel before dental caries form.
[15]
Early studies from Finland in the 1970s found that a group chewing sucrose gum had 2.92 decayed, missing, or filled (dmf) teeth compared to 1.04 in the group chewing xylitol gums.
[16] Recent research
[17] confirms a
plaque-reducing effect and suggests the compound, having some chemical properties similar to sucrose, attracts and then "starves" harmful micro-organisms, allowing the mouth to remineralize damaged teeth with less interruption. (However, this same effect also interferes with
yeast micro-organisms and others, so xylitol is inappropriate for making yeast-based
bread, for instance.) This is because
cariogenic bacteria prefer fermentable
six-carbon sugars, or
disaccharides such as sucrose, as opposed to the nonfermentable xylitol, whose antimicrobial properties then "starve" the bacteria, reducing their growth and reproduction.
[15] Most of these studies suggest that at least 6 grams of xylitol per day is needed for dental efficacy; for most chewing gum or breath mints this would require 12 pieces per day (op cit).
Xylitol is specific in its inhibition of the
mutans streptococci group, bacteria that are significant contributors to tooth decay.
[18] Xylitol inhibits mutans streptococci in the presence of other sugars, with the exception of
fructose. Daily doses of xylitol below 3.44 grams are ineffective, and doses above 10.32 grams show no additional benefit.
[19]
Saliva containing xylitol is more
alkaline than
saliva which contains other sugar products. After taking xylitol products, the concentration of basic
amino acid in saliva may rise. When saliva is
alkaline (i.e., its
pH is above 7),
calcium and
phosphate salts in saliva start to precipitate into those parts of enamel where they are lacking.
[6]
Xylitol also inhibits the growth of
Streptococcus pneumoniae, as well as the attachment of
Haemophilus influenzae on the
nasopharyngeal cells, making xylitol nose spray a very marketable product.
[15]
However, despite these promising conjectures two
systematic reviews of clinical trials could not find conclusive evidence that Xylitol was indeed superior to other polyols, i.e. Sorbitol (
Mickenautsch and Yengopal, 2012) or equal to that of topical fluoride in its anti-caries effect (
Mickenautsch and Yengopal, 2012b).
Xylitol-based products are allowed by the
U.S. Food and Drug Administration to make the medical claim that they do not promote dental cavities.