Daily use of xylitol lozenges did not result in a statistically or clinically significant reduction in caries among adults with an elevated risk of developing caries, according to a study in the Journal of the American Dental Association (January 2013, Vol. 144:1, pp. 21-30).
A team of researchers from several U.S. academic institutions conducted the three-site, placebo-controlled, randomized study, dubbed the Xylitol for Adult Caries Trial (X-ACT). It was designed to test the hypothesis that daily use of xylitol lozenges reduces dental caries incidence in adults with an elevated risk of caries.
While several reviews of the effectiveness of xylitol have been conducted over the past decade, their conclusions have differed considerably, the study authors noted. "Some conclude that there is evidence for a caries-preventive effect of xylitol, and others indicate that the evidence is inconclusive," they wrote. This prompted their effort to conduct a randomized controlled trial and supplement the existing evidence.
For the X-ACT trial, 691 participants ages 21 to 80 consumed five 1.0-gram xylitol or placebo lozenges daily for 33 months and underwent clinical examinations at baseline and at 12, 24, and 33 months.
While the xylitol lozenges reduced the caries increment 10%, the researchers reported, this reduction, which represented less than one-third of a surface per year, was not statistically significant.
"The results of this clinical trial did not demonstrate a statistically significant reduction in 33-month caries incidence either in the primary analysis or in the secondary analysis that included all three sites," the study authors wrote.
These results support findings in other reviews in which researchers determined that the evidence was inconclusive or that xylitol has little or no effect on caries increments.
The study differs from most previous studies in that it involved evaluation of lozenges (mints) rather than chewing gum, they added, "thereby rendering inoperative one possible method of action: mechanical plaque removal. Mints may be less effective than gum for this reason."