Xylitol and sorbitol effects on the microbiome of saliva and plaque.
Level 2 - randomized trial
Randomized crossover trial
PubMed 30598728 · doi:10.1080/20002297.2018.1536181
What was done
Thirty participants completed a randomized crossover trial evaluating the effects of xylitol- versus sorbitol-containing chewing gum on saliva and plaque microbiomes. Following a baseline washout period, participants chewed either xylitol or sorbitol gum for three weeks, completed a second four-week washout period, and then crossed over to the alternate gum for three weeks. Saliva and plaque microbial communities were profiled before and after each intervention period using 16S rRNA gene high-throughput sequencing.
What was found
Neither xylitol nor sorbitol significantly changed the overall bacterial composition of dental plaque. Lactobacilli were undetected, and Streptococcus mutans sequence reads were very low and unaffected by either gum. Salivary microbial community shifts varied depending on treatment order. Sorbitol consumption significantly altered several salivary streptococcal species, including an increase in the relative abundance of Streptococcus cristatus. The abstract reported no specific numerical values or effect sizes.
Why it matters
While polyol gums are widely promoted for caries prevention via reduction of cariogenic bacteria, short-term consumption did not alter plaque composition or S. mutans levels, suggesting oral microbiome effects may be subtle or mediated via commensals like S. cristatus.
Limits
The sample size was small (n = 30), and the intervention duration was short (three weeks). The baseline abundance of cariogenic species (S. mutans and lactobacilli) was extremely low or undetectable in this cohort, limiting the ability to assess reductions. Clinical dental outcomes (such as caries development or plaque index) were not measured.
Cited by
- contradicts Xylitol feeds beneficial oral bacteria, stops plaque bacteria from multiplying on teeth, and makes plaque less adhesive.