I find that I always go in and out of “mouthwash phases.” Sometimes I convince myself that it is an absolutely necessary component of my oral health routine, while in other moments in life I concede that a two-minute brush and a good flossing will suffice. However, I recently have been finding the mouthwash section of the pharmacy less appealing. I figure now is as good a time as ever to answer a reader’s query: What’s the scoop on using mouthwash? Will it deplete my nitrous oxide?
A Short History
While references to mouthwash appear in ancient literature, it is generally difficult to date the product’s origins. It has been said that around 94 BCE, the ancient Chinese gargled salt water, tea, and wine after meals in order to cleanse the mouth. Farther west, in 460-377 BCE, among the Greeks and Romans, mouth rinsing was common practice for the upper class, with our good friend Hippocrates recommending a solution of salt, alum, and vinegar as an effective mouthwash. While still debated, it has even been said that at the beginning of the common era, Roman mouthwash was just Portuguese urine. Yes, that specifically. The Romans were known to have an affinity for white teeth, and the ammonia in urine was thought to not only disinfect mouths but also give consumers those desired pearly whites.
Throughout the centuries, alcohol was commonly used in mouthwash due to its known antiseptic properties. At the end of the 19th century, with toothpaste usage on the rise, bottled mouthwash also had its big break. However, it would be another 100 years before researchers discovered the benefits of chlorhexidine. Chlorhexidine is a powerful prescription antiseptic that kills bacteria responsible for gum disease, plaque, and gingivitis. In the early 1990s, alcohol and chlorhexidine-free mouthwash hit the store shelves, as an over the counter (OTC) dental hygiene product. These formulas use fluoride, a compound that prevents cavities and tooth decay, and may even whiten teeth – of course, when combined with twice daily brushing.
But where does nitrous oxide fall into all of this?
The Scoop on Nitrates, Nitrites, and Nitrous Oxide
Nitrates and nitrites are often spoken about in the context of ultra-processed and preserved meat. Excess amounts of nitrates in the body may increase one’s risk for a plethora of health problems and increase one’s risk of cancer. However, nitrates are also found naturally in many fruits and vegetables. When we consume these dietary inorganic nitrates, they are converted into nitrites by the bacteria in our mouths. These nitrites then produce nitric oxide (NO), which, in moderation, has several health benefits. Most notably, the impact of nitric oxide on cardiovascular health has been well studied and documented, as well as its vasodilating effect when it comes to erections. Viagra actually works by boosting levels of nitric oxide. In fact, low bioavailability of NO (less NO in your body) has been associated with several illnesses such as diabetes, hypertension, and sepsis.
This all becomes important when we think about why mouthwash exists in the first place: to rid your mouth microbiome of “bad” bacteria. There are two main types of mouthwashes, antibacterial and antiseptic. Those that fall into the antibacterial category are mouthwashes that only target bacteria. Antiseptic mouthwashes, including, for example, chlorhexidine, target a vast array of organisms – not just bacteria. The well-known toothpaste and oral health brand, Colgate, claims that “you can be confident that the rinse is designed to inhibit microbes that could be harmful to your oral health.” What about microbes that are beneficial to our bodily health?
This is still an evolving field of research; the long-term effects of chronic mouthwash usage have not yet been well documented. However, some studies show a depletion in levels of NO among subjects who use both an antiseptic and an OTC mouthwash. Some studies have found that this may be associated with increased hypertension, inflammation, and diabetes. In one 2020 study, researchers found that participants who used OTC mouthwash more than twice daily had an 85% higher risk of physician-diagnosed hypertension compared with those who used mouthwash less frequently. Notably, these diagnoses were independent of other major hypertension risk factors.
Unfortunately, published studies on this subject are few and far between, making the assessment of the validity of these health claims difficult. Furthermore, the Canadian Dental Association still recommends adding mouthwash, “to a regular oral hygiene routine [as it] reduces and prevents gingivitis more than brushing and flossing alone.”
My thoughts? Next time I am at the store, I will probably go for bottle of bright blue liquid. At least it’s not urine! Neither do I have to worry about impotence.
Eva Kellner is a recent graduate from the Faculty of Arts and Science, with a major in Environment. Her research interests include urban green spaces, urban agriculture, and outdoor community spaces - all as promoters of climate resilience among city-dwellers.
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