- The primary mechanism by which xylitol prevents dental caries is through its ability to inhibit bacterial glycolysis by forming non-metabolizable intermediates.
- Xylitol is a sugar alcohol that oral bacteria, particularly Streptococcus mutans, uptake similarly to regular sugars. However, unlike fermentable sugars such as glucose or sucrose, xylitol cannot be fully metabolized by these bacteria.

- When bacteria take up xylitol, it is phosphorylated to xylitol-5-phosphate but cannot proceed further along the glycolytic pathway.
- This accumulation of non-metabolizable intermediates leads to disruption of bacterial energy production and inhibits acid formation.
- Since acid production is a key factor in enamel demineralization and cavity formation, reducing acidogenic activity helps prevent dental caries.

Additionally, regular xylitol exposure can reduce the number of cariogenic bacteria in dental plaque by interfering with their growth and adhesion capabilities. This contributes to a less cariogenic oral environment.

It is important to note that xylitol's caries-preventive action is distinct from fluoride’s mechanism, which works primarily by enhancing remineralization and inhibiting demineralization of enamel.

Key points:
- Xylitol is taken up by cariogenic bacteria but forms non-metabolizable intermediates.
- This action inhibits bacterial glycolysis and acid production.
- Reduced acid production decreases enamel demineralization and caries formation.
- Xylitol also reduces cariogenic bacterial counts in plaque.

Reference: Ten Cate's Oral Histology: Development, Structure, and Function, 9th Edition, Chapter 14 - Caries and Remineralization