A surprising study published in The Scandinavian Journal of Medicine & Science in Sports found a link between heavy training and a number of dental problems. This study supports an earlier study published in The British Journal of Sport Medicine and was conducted during the 2012 London Olympics. It found that a majority of the 278 athletes examined from around the world had evidence of gum disease, eroded tooth enamel and tooth decay.
The researchers did not elaborate further on the causes of these dental problems, but suspected that sports drinks and bars - which often contain large amounts of sugar - were the likely culprits.
To help narrow down the problem, researchers from the University Hospital Heidelberg gathered 35 triathletes and 35 non-athletes of similar demographics for an experiment. The subjects had a full oral exam, including a baseline saliva analysis and completed a questionnaire that asked the individuals about diet, hygiene and exercise habits.
A sampling was taken from some from the athletic group as they began a 35-minute run where their saliva was collected regularly.
Researchers then compared all of the saliva and found surprising results. Athletes had higher levels of enamel erosion and more cavities, with a positive correlation between number of cavities and time spent working out.
But, they found no correlation between sports drinks - or any part of the athlete's diet - and oral health. Nor did they discover a difference in the chemical composition between the resting saliva of the athletes and the control group.
The study did discover that as the athlete exercised they produced less and less saliva and the composition of the saliva shifted to be more alkaline. This combination of dryness and alkaline creates a great environment for plaque to grow. This occurred regardless of whether the athlete consumed water or a sport drink prior to exercising.
If you are an endurance athlete, or just enjoy long runs, you can protect your teeth. Drinking water will not hurt, but there is no strong empirical evidence to suggest a link between hydration and oral health. The best thing you can do is visit your dentist regularly, or see a dentist who specializes in sport dentistry.