Adding to the Caries Prevention Arsenal

What is Xylitol?
Phipps: Xylitol occurs naturally in a variety of fruits and vegetables but at a level generally less than 1%. The primary source for the commercial sweetener is birch trees and other hard wood trees with the majority of production in the United States, Finland, and China.

How sweet is Xylitol and why isn’t it used in more products?
Phipps: Xylitol is as sweet as sucrose. However, it is very expensive to produce so less expensive sweeteners like Sorbitol and other sugar alcohols are used more often.

What is the relationship between Xylitol and caries prevention?
Phipps: Xylitol, along with other sugar alcohols, is not fermented by oral bacteria so it cannot cause caries. In addition, several laboratory and clinical studies have found that chewing a Xylitol gum or sucking on Xylitol candy has other effects, along with reducing plaque quantity, such as reduced adhesion of plaque flora, reduced transmission of Mutans Streptococci, and the fact that it changes both the quantity and the quality of saliva, thus aiding remineralization.2

We know that Xylitol is a sweetener and does not ferment and so it does not enhance the caries process. Why is this therapeutic in terms of preventing caries?
Bruerd: In laymen’s terms, Xylitol is a five-carbon sugar alcohol and is taken in as food by those bacteria that cause dental caries but the bacteria can’t use a five-carbon sugar alcohol, so they die. Xylitol actually decreases the cavity-causing bacteria. It also returns an acidic saliva back to basic saliva so it has a different therapeutic effect after a meal. Chewing a piece of Xylitol gum after meals creates caries protection when brushing or flossing is not an option.

What are the dental applications and benefits of Xylitol use?
Phipps: One landmark longitudinal study showed that chewing a Xylitol gum three to five times a day actually stops the transmission of S. Mutans from mother to child.3 Other studies have shown that Xylitol gum and Xylitol candy prevent the development of new carious lesions in both children and adolescents.4-6

Who should be targeted for Xylitol therapy or Xylitol use?
Bruerd: First of all, I think any patient who’s at high risk for dental caries including those with any exposed root surfaces or xerostomia. We recommend it for 4- and 5-year olds in Headstart and fourth and fifth graders in elementary school. These age groups were chosen to maximize the effect on the first and second permanent molars. Another group that is supported in the literature is mothers and the effect on their children from birth to age 2.7 This is when the child colonizes bacteria that cause dental caries. Xylitol use during this stage can actually prevent colonization of those cavity-causing bacteria in an infant and prevent future dental caries for the child.

Phipps: Adults can also experience a reduction in the development of a new caries lesion, although clinical trials have not been performed on adults. Since the reduction occurs in children and adolescents, we can also assume that there is the same reduction in adults.

Because caries is a transmissible disease, do the same recommendations for Xylitol use for mothers apply to caregivers if the mother is working outside of the home?
Bruerd: It wouldn’t be a bad idea especially if the caregiver is taking care of several babies. This type of caregiver needs to have a lower S. mutans count. Interestingly enough, even children in day care will often adopt the S. mutans level of their mother and the only apparent reason is that mothers and infants share saliva more often. For example, infants often stick their hands in mom’s mouth. Although, we are finding that kids in day care can mirror many people whom they come in contact with.

Where is Xylitol found in dental products?
Phipps: On a therapeutic level, the primary source is gum and candy (Table 1). The dosage is key. Therapeutic doses from the completed clinical trials provide 6 to 10 grams of Xylitol per day. So a product with higher levels of Xylitol is necessary to obtain the therapeutic benefits. When reading the labels on products containing Xylitol, Xylitol should be the first sugar listed and, ideally, the only sugar included.

What are the complementary effects with fluoride?
Phipps: Fluoride inhibits demineralization of the tooth surface and promotes the rate of remineralization. For all patients, regular use of a fluoride toothpaste and fluoridated water is always recommended as the first step in caries prevention. However, Xylitol should be added to caries preventive regimen in high-risk patients as an additional preventive measure. When fluoride and Xylitol are combined in products such as toothpaste, the evidence is not available to show that the combination is significantly better than either fluoride or Xylitol alone. But the two together are complementary in a high-risk patient, so both therapies should be indicated. Additionally, Xylitol is great for xerostomic patients because they are at higher risk of caries. By sucking on Xylitol candy or Xylitol gum, rather than other sugared products, their risk of caries will decrease.

What is Xylitol’s effect on plaque?
Phipps: All chewing gum reduces the quantity of plaque but some evidence suggests that Xylitol gum is more effective in plaque reduction than both sugared and Sorbitol gums.8,9 In addition, results of several studies suggest that Xylitol specifically inhibits the growth of S. Mutans and decreases the amount of insoluble plaque polysaccharides that actually make plaque less adhesive to the tooth surface.10-12

Does Xylitol have any contraindications?
Phipps: Xylitol can cause osmotic diarrhea at 100 grams per day in adults and 45 grams per day in children. The dose for dental caries prevention is 6-10 grams per day. For people with temporomandibular joint problems, chewing gum should be avoided so Xylitol candy should be recommended.

Is Xylitol the magic bullet in preventing caries?
Bruerd: The magic bullet in preventing dental caries will be a caries vaccine. Unfortunately, this is not available yet. The biggest drawback to Xylitol therapy is that the patient needs to use Xylitol several times a day over a period of 6 months, 1 year, 2 years, and this requires compliance. We are relying on the patient to follow through with systematic Xylitol exposure in order to prevent the disease and, unfortunately, a lot of early childhood caries happens in families that are often least likely to comply with this sort of regimen. However, Xylitol is definitely something very valuable to add to our arsenal against dental caries.

Does this therapy mean that we can abandon good plaque control measures?
Bruerd: What Xylitol does is prevent dental caries. Brushing and cleaning habits are part of maintaining overall oral health. All of these have a place in the tool kit used to prevent dental caries. And in fact, children at high risk for dental caries need to use several tools. It’s very important that they brush every day with a fluoride toothpaste. These children will also benefit from an over-the-counter fluoride mouthrinse and from a Xylitol regimen. I would recommend to all hygienists who have access, particularly those in public health, to institutionalize Xylitol in a program that already exists, like Headstart or an elementary school. You can train the teachers and ensure that the children are getting it three times a day. That’s when we are going to see a bigger level of reduction among populations.

References

1. Xylitol Technical Properties. Surrey, United Kingdom: Danisco Sweeteners Ltd; 2004:17.
2. Maguire A, Rugg-Gunn AJ. Xylitol and caries prevention-is it a magic bullet? Br Dent J. 2003;194(8):429-436.
3. Soderling E, Isokangas P, Pienihakkinen K, Tenovuo J. Influence of maternal xylitol consumption on acquisition of mutans streptococci by infants. J Dent Res. 2000;79:882-887.
4. Kovari H, Pienihakkinen K, Alanen P. Use of xylitol chewing gum in daycare centers: a follow-up study in Savonlinna, Finland. Acta Odontol Scand. 200361(6):367-370.
5. Alanen P, Isokangas P, Gutmann K. Xylitol candies in caries prevention: results of a field study in Estonian children. Community Dent Oral Epidemiol. 2000;28(3):218-224.
6. Makinen KK, Bennett CA, Hujoel PP, et al. Xylitol chewing gums and caries rates: a 40-month cohort study. J Dent Res. 1995;74(12):1904-13.
7. Isokangas P, Soderling E, Pienihakkinen K. Alanen P. Occurrence of dental decay in children after maternal consumption of xylitol chewing gum, a follow-up from 0 to 5 years of age. J Dent Res. 2000;79:1885-1889.
8. Makinen KK, Hujoel PP, Bennett CA, et  al. A descriptive report of the effects of a 16-month xylitol chewing-gum programme subsequent to a 40-month sucrose gum programme. Caries Res. 1998;32:107-112.
9. Makinen KK, Chen CY, Makinen PL, et al. Properties of whole saliva and dental plaque in relation to 40-month consumption of chewing gums containing xylitol, sorbitol of sucrose. Caries Res. 1996;30:180-188.
10. Rekola M. Comparative effects of xylitol- and sucrose-sweetened chew tablets and chewing gums on plaque quantity. Scand J Dent Res. 1981;89:393-399.
11. Soderling E, Isokangas P, Tenovuo J, Mustakallio S, Makinen KK. Long-term xylitol consumption and mutans streptococci in plaque and saliva. Caries Res. 1991;25:153-157.
12. Soderling E, Alaraisanen L, Scheinin A, Makinen KK. Effect of xylitol and sorbitol on polysaccharide production by and adhesive properties of Streptococcus mutans. Caries Res. 1987;21:109-116.

From Dimensions of Dental Hygiene. October 2004;2(10):16, 18.