What level of anti-cavity protection can xylitol provide?

Dental plaque reduction effects attributed to the short-term use of xylitol.

Some of the early evaluations of xylitol involved four and five-day studies where the diet of the participants was altered so to included caramels, sweet rolls, and beverages sweetened with xylitol. At the end of these time periods, it was found that this xylitol consumption resulted in a 50% reduction of dental plaque.

The assumption associated with these findings was that the xylitol exposure had an effect upon the bacterial that live in dental plaque that, at least initially, seriously affected their ability to thrive. The net result was a reduction in their numbers, as evidenced by an observed reduction in the amount of dental plaque.

Cavity prevention effects attributed to the long-term, habitual consumption of xylitol products.

A number of studies performed since the mid seventies have reported that the daily consumption of a threshold amount of xylitol over an extended period of time can provide a significant benefit in terms of tooth decay reduction. These studies, involving xylitol use over one to three-year time periods, reported that the incidence of dental cavities can be reduced on the order of thirty to eighty-five percent during those years of continued xylitol use.

Residual decay prevention effects in those who have ceased to consume xylitol regularly.

There is an interesting phenomenon associated with people who have a history of habitually consuming xylitol (say on the order of at least a year) but have since quit. Studies have shown that these people still derive the benefit of reduced levels of tooth decay formation, even for some years after they have terminated their xylitol consumption.

The amount of cavity reduction associated with this residual effect can be on the order of ninety percent. However, the timing of the person's exposure to the xylitol is critical in determining the degree of protection that can be expected. Or, more precisely, the degree of benefit that is provided for specific teeth.

Take the case of a child who is at a point where about half of their baby teeth have been replaced by the eruption of their permanent teeth. In this situation, research has shown that the following levels of cavity protection might be expected.

• Observed protection for teeth that erupted before xylitol use was begun.
       No reduction in tooth decay formation.
  
  
• Observed protection for teeth that erupted after the first full year of habitual xylitol use.
       A 93% reduction in tooth decay.
  
  
• Observed protection for teeth that erupted after one full year of habitual xylitol use had been terminated.
       An 88% reduction in dental cavities.

These results may seem strange, even mystical, but they can be explained in the light of a hypothesis composed of the following two points.

In order to achieve the residual anti-cavity benefit of xylitol, its use should be started at least one year prior to the eruption of a child's teeth.

Cavity prevention benefits passed on to the children of mothers who habitually use xylitol.

Streptococcus mutans bacteria (one of the primary culprits associated with the formation of tooth decay) are usually acquired by children from their mothers (via salivary contacts) somewhere between the ages of 19 and 31 months. The timing of this initial infection is associated with that time frame when a child's teeth first come in. This is because in order to colonize a mouth, Streptococcus mutans bacteria typically require tooth surfaces on which to live.

The idea has been suggested that if a mother habitually consumes xylitol, at least a year before the target window for the eruption of her child's first teeth (age 7 months), her mouth will be inhabited by strains of Streptococcus mutans bacteria that are relatively less virulent. It will, therefore, be these strains that will be seeded to the child's oral environment and be the initial colonizers of the surfaces of their teeth.

This scenario should provide tooth decay prevention benefits such as those described above. As proof of this hypothesis, Isokangas (2000) found that the children of mothers who chewed gum sweetened with xylitol had 70% fewer dental cavities than the children of mothers who did not.