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Erosive Tooth Wear, but Not Dental Caries, Is Associated with Habitual Physical Activity and Athletic Participation: A Systematic Review and Meta-Analysis of Controlled Comparisons

This systematic review and meta-analysis concludes that habitual physical activity and athletic participation are significantly associated with an increased risk of erosive tooth wear but not with dental caries, likely due to exercise-linked chemical exposures rather than bacterial fermentation.

Original authors: Owen R. Thornton, Wenjun Li

Published 2026-08-12

📖 6 min read🧠 Deep dive

CC BY 4.0

Original authors: Owen R. Thornton, Wenjun Li

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

The Mouth, the Marathon, and the Mystery of the Missing Cavities

Imagine your mouth as a busy, high-tech factory. Inside, two very different kinds of troublemakers are constantly trying to break in. The first is the "Bacteria Band," a gang of tiny microbes that love sugar. When they feast on sweets, they throw acid parties that eat away at your teeth, creating holes we call cavities. The second troublemaker is the "Acid Storm," a chemical force that doesn't need bacteria at all. It happens when you drink something super sour or when your mouth's natural defense system—your saliva—takes a nap, leaving your teeth vulnerable to dissolving.

Now, picture a group of people who are always on the move: athletes, runners, and gym-goers. They are the factory's most active workers. For years, dentists have noticed that these hardworking folks seem to have a lot of dental trouble. But here is the big question that scientists have been scratching their heads over: Is it because they are active, or is it just because they happen to be athletes? Are they getting more cavities because they run so much, or is there a different, sneaky reason why their teeth are wearing down? This is the puzzle a new study set out to solve, trying to figure out if the lifestyle of an athlete actually changes the rules of dental health.

The Great Dental Detective Story

In this new research, two scientists from the University of North Carolina decided to play detective. They didn't just look at athletes; they looked for studies that compared athletes to regular, non-athletic people. Think of it like a side-by-side race: on one track, you have the super-fit crowd, and on the other, you have the folks who prefer a quiet evening on the couch. The goal was to see if the fit crowd had more "Acid Storm" damage (erosive tooth wear) or more "Bacteria Band" damage (cavities) than the couch potatoes.

The researchers gathered six different studies, involving over 1,000 people, and crunched the numbers using a special math tool called a meta-analysis. This tool is like a giant magnifying glass that combines small clues from many different places to reveal a bigger picture.

The Big Discovery: The Acid Storm Wins
The results were surprisingly clear for one type of damage. The study found that people who exercise habitually or compete in sports are 5.58 times more likely to have erosive tooth wear than those who don't exercise as much. To put that in perspective, if you imagine a group of 100 non-athletes with a few worn-down teeth, you'd expect to see nearly 600 people with worn-down teeth in a group of 100 athletes. That is a massive difference!

The scientists believe this happens because of a perfect storm of chemistry. When athletes train hard, they often chug sports drinks, gels, or juices that are very acidic. At the exact same time, their bodies are working so hard that their mouths produce less saliva. Saliva is like a natural shield that washes away acid and neutralizes it. Without enough of this shield, the acidic drinks eat away at the tooth enamel, causing it to dissolve. It's like pouring lemon juice on a piece of chalk while someone is holding a hose that usually sprays water to wash it off—the chalk just melts away.

The Mystery of the Missing Cavities
Here is where the story gets twisty. You might think that if athletes are drinking sugary sports drinks, they would also have way more cavities. After all, sugar feeds the "Bacteria Band," right? But the study found no clear link between being an athlete and having more cavities. The numbers showed a slight increase, but it wasn't statistically significant—meaning it could just be a fluke. The confidence interval ranged from 0.61 to 4.75, which includes the possibility that there is no difference at all.

Why the difference? The researchers suggest that while athletes might drink sugary things, they are also usually very good at brushing their teeth and taking care of their mouths. They might rinse their mouths out after a race or use fluoride toothpaste, which stops the bacteria from doing their damage. So, the "Acid Storm" (chemical wear) wins the battle, but the "Bacteria Band" (cavities) gets stopped by good hygiene.

How Sure Are We?

The scientists are careful not to shout "We solved it!" just yet. They admit that the evidence is a bit shaky, rating the certainty of the erosion finding as "LOW" and the cavity finding as "VERY LOW." This is because the studies they looked at were small, and some of them didn't compare the groups perfectly (like comparing a 20-year-old athlete to an 18-year-old non-athlete). Also, they couldn't check for "publication bias," which is when studies with boring results (like "athletes don't have more cavities") get hidden in a drawer and never published.

However, the pattern is strong enough to make a guess. The fact that the erosion risk is so high and the cavity risk is not suggests that the main danger for athletes isn't the sugar, but the acid and the lack of saliva. The study also noted that this result held up even when they removed one study at a time, which makes the finding about erosion feel quite solid, even if the data is thin.

The Takeaway for the Curious

So, what does this mean for a teenager who loves sports or just likes to run around? It suggests that if you are an athlete, your teeth might be under attack from a different enemy than you think. It's not just about brushing away the sugar; it's about protecting your teeth from the acid storms of sports drinks and the dry mouth that comes with hard exercise.

The study doesn't tell us exactly how to fix it, but it points the flashlight in the right direction. It suggests that dentists should probably check athletes' teeth for wear and tear (erosion) just as carefully as they check for cavities. And for the athletes themselves, it might be a good idea to rinse with water after a sour drink and maybe wait a bit before brushing, to let the saliva do its job.

In short, the paper tells us that being an athlete is a double-edged sword: it builds strong muscles, but it might also melt your tooth enamel if you aren't careful. The "Acid Storm" is real, the "Bacteria Band" is being kept in check, and the only thing missing is a few more studies to be absolutely sure. But for now, the evidence suggests that if you're sweating it out on the track, you might want to keep an extra eye on your smile.

Technical Summary: Erosive Tooth Wear, but Not Dental Caries, Is Associated with Habitual Physical Activity and Athletic Participation

Problem Statement
While oral disease prevalence in athletes is well-documented, existing meta-analyses have focused solely on prevalence rates within athlete populations without comparing them to non-athlete or less-active control groups. Consequently, the central epidemiological question remains quantitatively unanswered: do athletes and habitually active individuals carry a higher burden of oral disease compared to comparable sedentary populations, and if so, which specific conditions are affected? Furthermore, because erosive tooth wear (a chemical process driven by acid exposure and reduced salivary flow) and dental caries (a bacterial fermentation process) follow distinct causal pathways, it is hypothesized that physical activity may affect them differently. This review aims to resolve this gap by pooling controlled comparisons to estimate the odds of erosive tooth wear and dental caries in active versus inactive groups.

Methodology
This study is a systematic review and meta-analysis conducted in accordance with the PRISMA 2020 statement.

Search Strategy: A federated bibliographic search was performed across PubMed/MEDLINE, Scopus, and Semantic Scholar (inception through August 2026), supplemented by citation chasing of prior reviews and narrative reviews. No language or date restrictions were applied at the search stage, though retrieval was limited to openly accessible sources.
Eligibility Criteria: The review followed a PECO structure, including observational studies comparing an athlete/habitually active group against a non-athlete/lower-activity control group. Outcomes were strictly limited to erosive tooth wear or dental caries ascertained by clinical examination. Studies lacking a control group or reporting only prevalence were excluded.
Data Extraction and Synthesis: Six studies (1,042 participants) met the eligibility criteria. Effect sizes were expressed as odds ratios (OR). Random-effects models were fitted separately for erosive tooth wear and dental caries. Between-study variance ( $\tau^2$ ) was estimated using restricted maximum likelihood (REML), and confidence intervals were computed using the Hartung–Knapp–Sidik–Jonkman (HKSJ) variance correction to improve coverage in small samples.
Bias and Certainty: Risk of bias was appraised using the AXIS tool and Joanna Briggs Institute checklist. Certainty of evidence was rated using the GRADE framework. Funnel-plot asymmetry tests were pre-specified but withheld due to the small number of studies ( $k < 10$ ).

Key Results
The analysis yielded a clear dissociation between the two oral conditions:

Erosive Tooth Wear: There is a substantial association between physical activity/athletic participation and increased odds of erosive tooth wear.
- Pooled Estimate: OR 5.58 (95% CI 2.22 to 14.00; $p = 0.009$ ).
- Heterogeneity: Modest ( $I^2 = 47\%$ ; $Q(3) = 5.61, p = 0.132$ ). The REML estimate placed $\tau^2$ at the boundary (0.000).
- Robustness: The 95% prediction interval (1.61 to 19.34) excluded the null, and leave-one-out analysis confirmed the result was robust to the omission of any single study (range 4.41 to 5.94).
- Certainty: Rated LOW (downgraded for risk of bias and indirectness; upgraded for the large effect size).
Dental Caries: No clear association was demonstrated between activity status and dental caries.
- Pooled Estimate: OR 1.71 (95% CI 0.61 to 4.75; $p = 0.153$ ).
- Heterogeneity: Low ( $I^2 = 6\%$ ).
- Interpretation: The confidence interval comfortably includes the null, and the prediction interval (0.08 to 35.01) is extremely wide, spanning clinically important effects in both directions.
- Certainty: Rated VERY LOW (downgraded for risk of bias, indirectness, and imprecision).

Significance and Claims
The paper claims to be the first meta-analysis to quantitatively pool controlled comparisons of oral disease between athletes and non-athletes. Its primary significance lies in the dissociation of findings: habitual physical activity is strongly associated with erosive tooth wear but not with dental caries.

The authors argue this pattern supports a chemical-exposure model specific to exercise:

Mechanism: Erosion is driven by the combination of frequent ingestion of low-pH sports beverages and transiently reduced salivary flow during exertion.
Contrast: Caries requires bacterial fermentation and is more dependent on hygiene and fluoride exposure, factors where athletes do not necessarily differ from controls.
Implication: Screening protocols for athletes should prioritize erosive tooth wear, as it is the outcome most clearly linked to the athletic exposure. Preventive strategies should focus on reducing acid contact time and buffering capacity rather than solely addressing bacterial risk.

Limitations and Modesty
The authors explicitly frame these findings as guidance for screening priorities rather than definitive risk figures. They note several limitations:

Evidence Base: The small number of studies ( $k=4$ for erosion, $k=3$ for caries) renders heterogeneity statistics imprecise and prevents formal publication bias testing.
Study Design: All included studies are cross-sectional, precluding causal inference (though the authors note the biological implausibility of reverse causality).
Heterogeneity: Exposure definitions ranged from general physical activity to elite endurance sports, and control groups varied in age and sampling frames.
Retrieval Bias: Six potentially eligible reports could not be retrieved in extractable form, and the search was restricted to open-access sources.

The authors conclude that while the association with erosion is robust across the available data, the certainty of evidence is low, and the estimates should direct attention to the acid pathway in athletic populations rather than settle the question definitively.

The Mouth, the Marathon, and the Mystery of the Missing Cavities

The Great Dental Detective Story

How Sure Are We?

The Takeaway for the Curious

Technical Summary: Erosive Tooth Wear, but Not Dental Caries, Is Associated with Habitual Physical Activity and Athletic Participation

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