0913 GMT February 21, 2020
University College London (UCL) scientists interviewed 352 British athletes, including those preparing to compete at the 2016 Olympic Games in Rio, Brazil, BBC wrote.
It showed they were far more likely to brush twice a day and floss between their teeth, but still struggled.
Researchers said athletes need to take more steps to look after their teeth, such as high fluoride toothpastes.
Many previous studies have shown athletes from footballers to London 2012 competitors have problems with their oral health.
Around half of elite athletes in the UK have signs of tooth decay compared with around a third of similarly aged adults.
The latest study, published in the British Dental Journal, attempted to explore why.
Academics interviewed competitors from 11 sports, including cycling, swimming, rowing, hockey, sailing, athletics as well as rugby and football.
● 94 percent of athletes brushed their teeth twice a day compared with 75 percent of the general public
● 44 percent flossed regularly compared with 21 percent of the public
Smoking rates and overall diets were also much better in the elite athletes.
"However, they use sports drinks, energy gels and bars frequently during training and competition," said Dr. Julie Gallagher, one of the UCL researchers.
She added: "The sugar in these products increases the risk of tooth decay and the acidity of them increases the risk of erosion.
"This could be contributing to the high levels of tooth decay and acid erosion we saw during the dental check-ups."
● 87 percent used sports drinks
● 59 percent used energy bars
● 70 percent used energy gels
Other explanations include the mouth becoming dry due to breathing heavily during exercise so there is less protection from saliva in the mouth.
There are some suggestions poor oral health could have an impact on performance for reasons including less time spent in training.
At the pinnacle of elite sport, the difference between winning and losing is tiny, so even marginal improvements can make a crucial difference.
The report says athletes may need extra help with their teeth which could include very high fluoride toothpastes.
"Athletes were willing to consider behavior changes such as additional fluoride use from mouthwash, more frequent dental visits, and reducing their intake of sports drinks, to improve oral health," Gallagher said.
Pilot studies testing this have already been conducted, but the results are not yet known.