Should I worry about the microplastics in my floss and toothbrush?

While common sources like plastic bottles, cutting boards, and food containers are well-established contributors to microplastic exposure, a growing body of research suggests that everyday dental products—from toothbrushes to dental floss—may also be shedding these tiny fragments into our mouths and potentially, our bodies. This revelation adds another layer of complexity to the challenge of minimizing microplastic intake, prompting consumers to scrutinize even their most essential personal care routines.

The potential health consequences of microplastics are a subject of intense ongoing research. Some researchers, for instance, speculate that microplastics introduced into the oral cavity could disrupt the delicate microbial balance of the mouth, a state known as oral dysbiosis. This imbalance could potentially contribute to inflammation of the gums and other oral tissues, and there are even concerns that these particles could cause cellular damage, including DNA alterations, through mechanisms like oxidative stress. However, it is crucial to temper these speculations with the current scientific understanding. Dr. Bapanaiah Penugonda, a dentist at New York University, highlights that while the release of microplastics from dental products is plausible, the exact quantity released and whether this exposure translates into clinically meaningful health problems remains largely unclear. The field is nascent, and definitive conclusions are still far off.

Experts consistently emphasize that the fundamental benefits of maintaining rigorous oral hygiene far outweigh the presently speculative risks associated with microplastics from dental products. Brushing and flossing are cornerstones of preventing cavities, gum disease, and ultimately, tooth loss, all of which have well-documented systemic health implications. Therefore, the primary advice remains to prioritize these essential practices. For those concerned about microplastics, experts recommend focusing on more established and significant sources of exposure, such as household dust, synthetic fabrics in clothing and furnishings, and plastic kitchen tools, which are known to shed particles more abundantly. Nevertheless, researchers and dental professionals are beginning to offer practical insights into how individuals might subtly limit their exposure to dental microplastics without compromising their oral health.

Why Do Dental Products Release Microplastics?

The explanation behind the release of microplastics from dental products is rooted in the materials they are made from and the mechanics of their use. The vast majority of everyday dental products are constructed from various types of plastic polymers. Toothbrush bristles, for example, are predominantly made from nylon, a synthetic polymer renowned for its durability and flexibility. Similarly, dental floss is essentially a finely spun plastic thread, often made from nylon or PTFE (polytetrafluoroethylene), more commonly known as Teflon.

As individuals engage in the routine actions of brushing and flossing, mechanical friction—the rubbing of bristles against teeth and gums, or floss against tooth surfaces—inevitably causes wear and tear. This constant abrasive action can lead to the gradual degradation of the plastic material, resulting in the shedding of tiny fragments or fibers. Dr. Federica Di Spirito, an oral surgeon at the University of Salerno in Italy, explains that these minuscule plastic particles are then released directly into the oral cavity. Over time, the bristles of a toothbrush visibly fray and splay, a clear indicator of this degradation process.

For products like toothpaste and mouthwash, the concern regarding microplastics primarily shifts from the product itself to its packaging. The ubiquitous plastic tubes and bottles used for these items are typically manufactured through processes involving heating and forming plastic resins. During these stages, and throughout the product’s shelf life, microplastics can leach from the packaging material into the product contents. Sanjay Mohanty, an environmental engineer at the University of California, Los Angeles, notes that this phenomenon is a known characteristic of plastic containers. It’s worth remembering that many toothpastes historically contained plastic microbeads—tiny plastic spheres added for their abrasive qualities to help scrub and polish teeth. However, public outcry and environmental concerns led to the "Microbead-Free Waters Act" in the United States in 2015, which banned their inclusion in rinse-off cosmetics, including toothpaste, marking a significant step in reducing a direct source of microplastics in oral care.

Despite these known mechanisms of release, Dr. Di Spirito underscores that researchers currently lack sufficient data to definitively quantify whether dental products constitute a major source of microplastics when compared to the myriad other sources present in our daily lives. While the theoretical pathways for microplastics to enter the body through the mouth are clear—they could potentially penetrate through microscopic breaks in the gum tissue, pass through the permeable mucous membranes lining the mouth, or simply be swallowed with saliva and food—the actual extent to which this occurs remains largely undetermined. Dr. Mohanty aptly summarizes this uncertainty: "Just because microplastics are released doesn’t mean that they’re going into our body." A significant portion of these particles might simply be spat out or rinsed away.

Are There Non-Plastic Alternatives?

The growing awareness of microplastics has naturally led consumers to seek out non-plastic alternatives for their daily routines, including dental care. However, experts generally advise caution and emphasize that there are currently no universally recommended non-plastic toothbrushes, flosses, toothpastes, or mouthwashes specifically endorsed for significantly reducing microplastic exposure. The primary reason, as highlighted by Dr. Dimitrios Michelogiannakis, an orthodontist at the University of Rochester, is the scarcity of robust, independent testing that quantifies the microplastic release from different dental products, both plastic and non-plastic. Without such data, making definitive recommendations is challenging.

Furthermore, existing non-plastic alternatives often present trade-offs in terms of cost, comfort, performance, and even other environmental considerations.

• Toothbrushes: Bamboo-handled toothbrushes have gained popularity as an eco-friendly option, as they reduce the plastic waste associated with the handle. However, the bristles are still typically made from nylon, meaning the primary source of potential microplastic shedding inside the mouth remains. Some bamboo toothbrushes claim to use "bioplastics" or plant-based bristles, but these can still be polymers and their degradation and shedding characteristics are not yet fully understood. Another alternative is boar hair bristles, derived from animals. While natural, Dr. Michelogiannakis points out that these can be quite harsh on gums, potentially causing damage, and they also tend to dry less efficiently, which can increase the risk of bacterial growth.
• Dental Floss: Silk floss is a natural, biodegradable alternative to plastic floss. However, practical application can be a challenge. One study comparing silk floss to three common plastic flosses found that the silk version was rated least comfortable and pleasant to grip. It was also more prone to fraying, shredding, and snapping during use, which could hinder effective cleaning and potentially leave behind natural fibers that, while biodegradable, might still be perceived as foreign particles. Other emerging alternatives include floss made from corn starch or other plant-based polymers, but their long-term performance and shedding properties require further investigation. Water flossers, while often effective, still utilize plastic components and require regular maintenance.
• Toothpaste and Mouthwash: To circumvent plastic tubes and bottles, some companies offer toothpaste in dissolvable tablet form, packaged in glass jars or cardboard, or in aluminum tubes. Mouthwashes can also be found in glass bottles or as concentrated tablets. While these options might indeed help reduce exposure to microplastics originating from packaging, experts remain cautious. They cannot definitively state by how much this exposure is reduced, nor if the often higher price point for these alternatives is justified by a tangible health benefit, given the lack of specific comparative research.

The consensus among experts is that while exploring alternatives is commendable, the current scientific evidence doesn’t strongly endorse any particular non-plastic dental product as a definitive solution to microplastic exposure. The priority should remain on effective oral hygiene practices.

What to Do to Reduce Your Exposure to Microplastics?

Given the current state of scientific understanding, where the benefits of established oral hygiene practices far outweigh the unknown risks of microplastics from dental products, Dr. Di Spirito advises maintaining a clear focus on dental health. Preventing cavities, gum disease, and tooth loss are well-documented advantages of regular brushing and flossing, with significant positive impacts on overall systemic health. However, for those who wish to proactively minimize potential microplastic exposure, experts offer a few simple, research-limited modifications to their routine:

1. Brush and Floss Softly: Aggressive brushing is a common mistake that can lead to gum recession, enamel abrasion, and potentially, increased shedding of toothbrush bristles. Dr. Michelogiannakis advises being thorough but gentle. Using a toothbrush with soft bristles is highly recommended, as they are effective at cleaning without causing undue wear on teeth, gums, or the bristles themselves. When flossing, the technique involves gently slipping the thread between teeth, curving it around one tooth in a "C" shape, and then carefully sliding it up and down the tooth surface before repeating on the adjacent tooth. Gentle motions minimize friction and potential particle release.
2. Replace Your Toothbrush Regularly: Over time, plastic bristles degrade and fray, becoming less effective at cleaning and more prone to shedding microplastics. Dr. Michelogiannakis recommends swapping out your toothbrush at least every three to four months, or sooner if you notice visible signs of wear, such as splaying or fraying bristles. This practice not only helps reduce potential microplastic exposure but also ensures optimal cleaning performance and minimizes bacterial buildup on old bristles.
3. Avoid Sun and Heat Exposure: Plastics are susceptible to degradation when exposed to environmental stressors like ultraviolet (UV) light and high temperatures. Dr. Mohanty explains that these conditions can accelerate the breakdown of plastic polymers, making them more likely to shed microparticles. Therefore, it’s advisable to keep dental products, especially toothbrushes, out of direct sunlight. Similarly, avoid cleaning your toothbrush with UV light sanitizers or very hot water, as these can contribute to plastic degradation. Warm or cold water is perfectly adequate for rinsing and maintaining toothbrush hygiene, as confirmed by Dr. Michelogiannakis.
4. Spit Well, Consider a Light Rinse: After brushing or flossing, it’s good practice to thoroughly spit out any toothpaste residue and loosened plaque or food particles. Dentists typically advise against rinsing immediately after brushing to allow the fluoride in toothpaste to remain on the teeth, maximizing its cavity-preventing benefits. However, to address the concern of residual microplastics or grit, Dr. Mohanty suggests a slight modification: after spitting out the bulk of the toothpaste, a very small sip of water—just enough to swish gently and spit out—might help wash away any lingering particles without completely diluting the beneficial fluoride. This can be done by simply cupping a small amount of water in your hand.

While these tweaks are relatively minor, they represent a conscious effort to reduce potential microplastic exposure in a realm of daily life that has previously received less attention. However, it’s paramount not to allow these concerns to overshadow the foundational importance of oral health. As Dr. Di Spirito eloquently puts it, "The key message is risk management rather than panic." The scientific community continues its vital work in understanding the full scope of microplastic impacts, and as more robust data emerges, advice may evolve. For now, a balanced approach combining diligent oral hygiene with thoughtful, simple modifications to minimize exposure remains the most sensible path forward.

By Simar Bajaj © The New York Times Company

The article originally appeared in The New York Times.