Frequent Swimmer? Your Oral Health May be Grimmer

by Rachael Straus

A few months ago, a patient of mine sat down and proudly informed me she had “swimmer’s mouth.” It was the first time I had ever heard that term, but having only been practicing dental hygiene for 3 years, I assumed it was something I had perhaps missed while in school. Upon further inquiry, I discovered that not one of my dental hygiene colleagues had heard of “swimmer’s mouth” either. Historically, this patient has always had larger than usual calculus deposits in her mouth despite her diligent dental hygiene routine at home. As a solution, we had created a treatment plan to see her on a 3-month recall to assess her plaque levels then, but at the recall visit she still had the same heavy deposits located around her anterior teeth. When she was complaining about her high plaque levels in the locker room, her swimming coach told her not to worry – it was something all swimmers got and was called “swimmers mouth.” According to her swimming coach, no matter how often she brushes and flosses, she will always get plaque. In her chart, I noted multiple times about her competitive swimming but at no point was this fact connected to her higher-than-usual levels of calculus. This entire interaction piqued my interest and led me to research the phenomenon.

Swimming is one of the top recommended activities for all ages because it is a low impact exercise and easier on the bones and joints.1 According to the CDC, a person who swims just 2.5 hours a week has about half the risk of death compared to inactive people.2 Although swimming has many proven benefits, it can also negatively impact oral health because of the ingestion of pool water. In 2017, a study showcased that swimmers, on average, ingest 32mL of water per hour.3 This is about 5 cups of water in one hour just from swimming. Ingesting water is quite healthy and also beneficial for the oral environment; unfortunately, pool water contains chlorine and it is the chlorine chemical reaction that leads to increased plaque levels in the oral environment.

Calculus is formed when the pH in a person’s mouth drops below 7.0.4 When the pH of a person’s mouth begins to lower even further, to around 5.5, hard deposits start to crystalize5 because bacteria thrive in an acidic environment. These crystallizations become tartar or calculus. In North America, all pools are required to contain chlorine, a harsh chemical used to disinfect them. Chlorine is chosen because of its affordability and effectiveness. The pH of the pool will rise and lower depending on the levels or types of chlorine used. This is when swimming can become a threat to the oral environment. The lower the pH level of the pool, the more effective the chlorine and the cleaner the pool. A properly maintained pool typically has a pH of 7.4, which is higher than the usual pH of saliva. This is where the problem lies because when a person’s saliva interacts with a pool environment it causes the salivary proteins to break down quickly and form the dark brown deposit known as “swimmer’s mouth” or swimmer’s calculus.6

As a swimmer takes a breath before going under water, the anterior teeth are exposed to the chlorinated water. The difference between swimmer’s calculus and generic tartar is that bacterial tartar accumulates near the gum-line whereas swimmers’ calculus accumulates in the front of the mouth.7 Swimmer’s calculus deposits are typically found interproximally around the anterior teeth. It accumulates where the water passes through the teeth when swimming. Image A is a classic case of swimmers calculus. This patient was reported brushing 5x daily and received a dental prophylaxis 4 months prior to taking this photo.8 As you can see, it looks extremely similar to a patient with heavy supragingival calculus and, because of this, is often misdiagnosed and not identified as swimmer’s calculus. In order to identify “swimmers mouth,” one should gauge the regularity of dental visits, location of plaque, and diligence of oral hygiene routine. If those three things are assessed during the initial patient planning then it will be noted as swimmers calculus and can be treated as such.

Image A

swimmer’s mouth
Rose KJ, Clifton CM. Intensive Swimming: can it affect your patients’ smiles. The Journal of American Dental Association. 1995;126:1402-1403.

Since it’s pretty hard to completely avoid opening your mouth when swimming, we can’t consider it a viable solution. In 2017, a study was conducted with swimmers using a pre-fluoride solution. The swimmers were exposed to heavily fluorinated pools for 30 minutes a day. The study found that the swimmers treated with the fluoride treatment had increased protection from the erosive effects of chlorine.3 Though this treatment won’t eliminate or avoid the stains associated with swimmers calculus, it does protect the tooth structure beneath the hard calculus deposits or stains.9 Additionally, while some swimming coaches suggest immediately rinsing with a fluoride rinse or using a fluoridated dentifrice when exiting the pool, dental hygienists do not recommend this because chlorine softens the tooth enamel, which can more easily be brushed away if brushed immediately after being exposed to chlorine.10 Instead, the goal is to lower the pH of the mouth first, by rinsing with a fluoride rinse or even water immediately following the end of practice.

The goal of dental hygienists is to find the source of the problem and combat it with viable solutions. The most important key aspect of my research led me to understand that to help our patients who swim, we must first be able to identify swimmer’s calculus, which can easily be confused with a patient who has supragingival calculus. But once we recognize the signs we can then treat the patient appropriately to save the patient’s oral environment from damage.


  1. Moore AB, Calleros C, Aboytes DB, Myers OB. An assessment of chlorine stain and collegiate swimmers. Can J Dent Hyg. 2019 Oct 1;53(3):166-171. PMID: 33240355; PMCID: PMC7533807.
  2. Marsh PD. Microbial ecology of dental plaque and its significance in health and disease. Adv Dent Res. 1994;8:263–71.
  3. Dufour AP, Behymer TD, Cantú R, Magnuson M, Wymer LJ. Ingestion of swimming pool water by recreational swimmers. J Water Health. 2017
  4. Chase NL, Sui X, Blair SN. 2008. Swimming and all-cause mortality risk compared with running, walking, and sedentary habits in men. Int J of Aquatic Res and Educ. 2(3):213-23.
  5. D’ercole S, Tieri M, Martinelli D, Tripodi D. The effect of swimming on oral health status: Competitive versus non-competitive athletes. J Appl Oral Sci. 2016 Mar 1;24(2):107–13.
  6. Moore AB. Chlorine Stain and the Oral Cavity [Internet]. 2018 [cited 2020 Mar 22]. Available from: 2
  7. Guardian. How Does Chlorine in Pools Affect My Teeth? | Guardian Direct [Internet]. 2020 [cited 2020 Mar 22]. Available from: affect-my-teeth
  8. Rose KJ, Clifton CM. Intensive Swimming: can it affect your patients’ smiles. The Journal of American Dental Association. 1995;126:1402-1403.
  9. Boonviriya S, Tannukit S, Jitpukdeebodintra S. Effects of tannin-fluoride and milk- fluoride mixture on human enamel erosion from inappropriately chlorinated pool water. J Oral Sci. 2017;59(3):383–90.
  10. Centerwall, BS. “Erosion of Dental Enamel Among Competitive Swimmers at a Gas Chlorinated Swimming Pool.” National Center for Biotechnology Information. U.S. National Library of Medicine, Apr. 1986. Web. 23 Nov. 2014.

About the Author

Rachael Straus (AKA The Pink Hygienist) originally is from Atlanta, GA and graduated from New York University’s Dental Hygiene Program. Aside from finding out about the latest and greatest in dental hygiene, her interests include the color pink, makeup artistry, tennis and reading.

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