Xylitol is less proven than the packaging suggests. The best review of the research found only one result that held up reasonably well: fluoride toothpaste with added xylitol prevented a little more decay in children's adult teeth than fluoride toothpaste alone, and even that came from low-quality evidence. For xylitol gum, mints, lozenges and syrups, there was not enough good evidence to say whether they prevent cavities.
That does not make xylitol useless. It is a sweetener that does not feed decay, and chewing sugar-free gum after a meal does help saliva do its job. It is simply an optional extra, not a replacement for fluoride, brushing and keeping sugar down.
Why xylitol is kinder to teeth than sugar
Decay starts when bacteria in plaque ferment sugars and produce acid, which draws minerals out of enamel. Xylitol is a sugar alcohol. It tastes sweet, but the main decay-causing bacteria cannot ferment it into acid the way they ferment ordinary sugar. Swapping a sugary snack or lolly for a xylitol-sweetened one removes one acid attack.
Chewing also matters, separately from the sweetener. Any sugar-free gum chewed after eating increases the flow of saliva, which rinses food away and helps neutralise acid. Our article on sugar-free gum and teeth explains that effect.
What the Cochrane review found
The most thorough summary is a Cochrane review by Riley and colleagues, published in 2015, which pooled 10 trials with 5,903 participants. Most of the trials were at high risk of bias. Its findings, in plain terms:
- Over 2.5 to 3 years, a fluoride toothpaste containing 10% xylitol reduced decay in children's permanent teeth by about 13% compared with fluoride toothpaste alone. The evidence was low quality, and both trials came from the same research group and population.
- For xylitol lozenges, tablets, wipes and syrups in infants and children, the evidence was too weak or uncertain to show a benefit.
- For adults, there was a single small trial of lozenges, and its result was compatible with either a benefit or no benefit.
- Reported side effects from xylitol products included bloating, wind, cramps and loose stools.
Put simply, xylitol has a plausible way of helping, but good trials showing that it prevents cavities in everyday use are lacking.
Who might reasonably use it
Xylitol gum or mints can be a sensible swap for people who would otherwise reach for sugary lollies or mints through the day, and chewing sugar-free gum after meals is a reasonable habit for anyone at higher risk of decay or with a dry mouth. If you choose a xylitol product, the ones studied used xylitol as the main sweetener and were used regularly, not once in a while.
Start slowly. Larger amounts can upset the stomach, and the threshold varies from person to person. For young children, gum and hard mints are a choking risk, so check with your dentist before offering them.
The foundations still do the heavy lifting
The measures with strong evidence have not changed: brush twice a day with a fluoride toothpaste, clean between your teeth, keep sugary food and drinks to mealtimes rather than grazing, and have regular check-ups. Xylitol sits on top of those, never in place of them. Our guides to preventing cavities, how sugar leads to decay and fluoride safety cover these in more depth.
Keep xylitol away from dogs
Xylitol is safe for people in normal amounts but dangerous for dogs. Veterinary toxicology reviews describe severe low blood sugar and, in some dogs, liver damage after eating xylitol products. Store xylitol gum, mints and sugar-free baking out of a dog's reach, and contact a vet straight away if your dog eats any.
Common questions
Is xylitol gum better than other sugar-free gum?
Any sugar-free gum stimulates saliva. Xylitol has the added feature of not being fermented by decay bacteria, but trials have not shown clearly that xylitol gum prevents more cavities than other sugar-free gum.
Should I buy a xylitol toothpaste?
The fluoride is what matters most. The Cochrane review found low-quality evidence of a small extra benefit from xylitol in fluoride toothpaste for children, so it is a reasonable choice, but a standard fluoride toothpaste used well is the priority.
Can xylitol reverse a cavity?
No. Very early enamel changes can sometimes be helped to remineralise with fluoride and better habits, but a cavity that has formed a hole needs to be assessed and usually treated.
If you get cavities easily or have a dry mouth, a dentist or OHT can look at your risk factors and suggest a prevention plan that suits you. Book a check-up through our current offers.
Sources
- Riley P, Moore D, Ahmed F, Sharif MO, Worthington HV. Xylitol-containing products for preventing dental caries in children and adults. Cochrane Database of Systematic Reviews, 2015.
- Murphy LA, Dunayer EK. Xylitol toxicosis in dogs: an update. Veterinary Clinics of North America: Small Animal Practice, 2018.
This article is general information and not a substitute for personal dental advice. Please see a dentist for care tailored to your situation.
