Plenty of runners and cyclists come in for a check-up expecting a clean bill of health and are surprised to hear their enamel is showing wear. Fitness protects the heart and lungs, but it does nothing for teeth that sit in sugar and acid for three or four hours every weekend. The pattern of fuelling, the drying effect of hard breathing and the long gap between brushes all point the same way.
None of this means changing what you eat on a long session. Most of the protection comes from small changes in timing and rinsing.
Athletes have more dental disease than their fitness suggests
Studies of athletes keep finding more decay, erosion and gum inflammation than you might expect in such a healthy group. When dentists examined 278 athletes at the London 2012 Olympic Games, 55% had tooth decay, 45% had dental erosion and 76% had gingivitis, and nearly half had not seen a dentist or hygienist in the previous year (Needleman and colleagues, British Journal of Sports Medicine, 2013). A meta-analysis pooling five studies of athletes from a range of sports put the overall prevalence of decay at about 46% (Azeredo and colleagues, Indian Journal of Dental Research, 2020), with wide uncertainty because the studies were small.
Research on endurance athletes in particular is more limited. A German study compared 35 triathletes with 35 people who did not exercise (Frese and colleagues, Scandinavian Journal of Medicine and Science in Sports, 2015). The triathletes had a clearly higher risk of erosion. Overall decay rates were similar in the two groups, but among the triathletes, those who trained more hours each week tended to have more decay. That is a modest finding from a small group, and it is fair to say the risk is real without overstating it.
Frequent fuelling keeps the mouth acidic
Every time sugar reaches the plaque on your teeth, bacteria turn some of it into acid and the enamel surface loses a little mineral. Saliva then neutralises the acid and helps put mineral back. Teeth cope well with this cycle when sugar arrives a few times a day and the mouth gets long breaks in between.
A long run or ride removes the breaks. A gel, a few mouthfuls of sports drink, some chews, another gel: each one restarts the acid attack before the last has settled. Over a four hour session the surface of the teeth may spend most of that time under challenge. The total amount of sugar matters less than how often it arrives and how long it lingers.
Many sports drinks and gels are also acidic in their own right, so they can soften enamel directly as well as feeding decay bacteria. Carbohydrate mouth rinses, which some athletes swish and spit for a performance effect, keep sugar in contact with the teeth by design.
Hard breathing dries the mouth when it most needs saliva
Saliva is the mouth's main defence against both decay and erosion. During hard aerobic work most people breathe through the mouth, often for hours, and sweat losses add to the drying effect. In the Frese study, saliva flow in triathletes fell during an incremental running test as the workload rose.
So the mouth has less saliva at exactly the point it is receiving the most sugar and acid. If your mouth also feels dry on rest days, that deserves its own look, because medicines and some health conditions are common causes. Our article on dry mouth causes and treatment goes through them.
Long sessions and race weekends push back the toothbrush
Nobody brushes at the 30 kilometre mark. Early starts, travel to events, training camps and multi-day rides squeeze the usual routine, and the gap between the first gel and the next proper clean can stretch well past half a day.
There is also a habit common to people in a heavy training block: ignoring early symptoms. Sensitivity gets put down to cold air on a morning run. A sore tooth waits until after the race. Small problems found early are usually simpler to manage than the same problems found months later.
Protecting your teeth without changing your fuel
Please do not change a fuelling plan that works for your gut and your event on dental grounds alone. If you want to adjust it, a sports dietitian is the right person to talk to. The ideas below are about what happens around the fuel.
| What you use | Why it matters for teeth | What helps |
|---|---|---|
| Gels | Concentrated, sticky sugar that clears from the teeth slowly; many are also acidic | Swallow promptly and follow with a mouthful of plain water |
| Chews and blocks | Pack into the grooves of back teeth and between teeth, where sugar lingers longest | Follow with water, and clean between your teeth that evening |
| Sports drink | Constant small sips give the teeth no recovery time; most are acidic | Where the session allows, drink in larger mouthfuls less often, and carry a second bottle of water |
| Carbohydrate mouth rinse | Held in the mouth on purpose, which maximises contact | Rinse with plain water afterwards, and mention it to your dentist |
| Recovery shakes and drinks | Often sugary and sipped slowly over the drive home | Finish it in one go rather than over an hour, then rinse with water |
| Plain water | No sugar, no acid, and it helps wash both away | Carry it alongside your fuel |
After the session, rinse first and brush when it suits you
Advice used to be to wait half an hour or more before brushing after anything acidic. A 2024 scoping review in Caries Research (Fernández and colleagues) looked at the evidence and found that brushing with fluoride toothpaste soon after an acid exposure does not appear to add measurable wear. So there is no fixed wait you need to watch.
What does help after a gel-heavy session:
- Rinse your mouth with plain water as soon as you stop. It dilutes leftover sugar and acid straight away.
- Rehydrate with water, which also helps saliva flow return.
- Chew sugar-free gum if you like; chewing stimulates saliva.
- Brush with a fluoride toothpaste and a soft brush when it fits your routine, then spit rather than rinse so the fluoride stays on the teeth.
- Clean between your teeth with floss or interdental brushes that evening, since chews and gels collect exactly where a brush cannot reach.
People with reflux and regular ocean or pool swimmers face their own acid challenges, covered in acid reflux and your teeth and saltwater and chlorine tooth erosion. Triathletes can meet both the pool and the gels in the same week.
Clenching and mouth ulcers can follow heavy training
Many athletes clench or grind during hard efforts such as hill repeats, intervals and the final kilometres of a race, and in the gym work that most endurance programs now include. Jaw tightness after sessions, headaches around the temples and teeth that look flatter over time are worth mentioning at your next visit. Our piece on weightlifting and teeth clenching covers this in more detail.
Some athletes also notice more mouth ulcers or cold sores during big blocks of training. Most heal on their own. Any ulcer, patch or sore in the mouth that has not healed or has changed within three weeks should be checked by a dentist or GP.
What a check-up for an endurance athlete looks like
Tell your dentist or OHT how many hours you train, what you fuel with and how often. That information changes the advice. Someone sipping sports drink through long rides several times a week may be better suited to a shorter recall interval than the usual twelve months, along with a closer look at early erosion and extra fluoride where it is needed.
The everyday habits are not complicated: fluoride toothpaste twice a day, cleaning between the teeth, water around your fuel and regular checks. People who will ride for six hours in the rain have the discipline. What is often missing is simply knowing that the fuel has a dental cost.
As a general guide, a check-up and clean in Sydney typically costs $200 to $400 across the market, depending on what X-rays are needed and the practice. You can ask for a written treatment plan with fees before any treatment is booked.
Common questions from runners and riders
Do sugar-free sports drinks protect my teeth?
They take away the sugar that feeds decay, but most are still acidic, so they can still contribute to erosion when sipped constantly. They also provide little or no fuel, which may not suit a long session.
Does mouth breathing on a run harm my teeth by itself?
Not directly. It dries the mouth, and less saliva means teeth are more exposed to whatever sugar and acid is around. Combined with frequent fuelling, that is the main reason long sessions carry more risk than short ones.
Is it worse to rinse with a carbohydrate drink than to swallow it?
From the teeth's point of view, holding sugar in the mouth increases contact time. Whether the performance benefit is worth it is a decision for you and your coach. If you use one often, rinse with water afterwards and let your dentist know.
Booking around your training
Training hard and keeping healthy teeth are not in conflict. Water around your fuel, a clean between the teeth on big days and not riding out a niggle until after race season will cover most of the risk. If it has been a while since your last visit, or you have a big event coming up, see our current offers or read about general dental care at Lumi Dental. Our Melrose Park team can find a time that fits around your training week.
This article is general information only and is not a substitute for individual dental, medical or nutrition advice. Please speak with a qualified health practitioner about your own circumstances.
