Environmental Determinants of Oral Health – Linking Pollution, Housing, and Diet to Dental Inequities

When people think about oral health, they typically consider brushing, flossing, and visiting the dentist regularly. But oral health is more than personal hygiene or individual responsibility. It’s also shaped by the environment we live in. Across Canada and around the world, environmental injustice is silently eroding the oral health of marginalized communities. Whether through contaminated water, polluted air, or unsafe housing conditions, the places we live, breathe, and drink are deeply connected to the health of our teeth, gums, and mouths.

Environmental racism occurs when low-income and racialized communities are disproportionately exposed to pollution and environmental hazards because of systemic discrimination in environmental policy, planning, and enforcement.  These communities are more likely to be located near factories, highways, landfills, and in substandard housing. While we often hear about environmental injustice in the context of asthma and respiratory conditions, the impact it has on oral health is rarely discussed. Yet, the same environmental stressors that damage our lungs and hearts also harm our mouths, often in permanent ways.

Contaminated drinking water

One of the most direct connections between environmental conditions and oral health lies in access to clean, fluoridated drinking water. In many communities across Canada, especially in First Nations reserves, people have lived under long-term boil water advisories, sometimes for decades. As of August 2025, there are 39 long-term drinking water advisories in 37 First Nations communities. Despite Canada holding 20% of the world’s freshwater supply and Ottawa spending nearly $30 million on upgrades since 2017, Neskantaga First Nation, under a boil-water advisory for over 30 years, still lacks clean water in homes, which Chief Chris Moonias calls traumatic and unacceptable. Without access to safe water, basic oral hygiene practices like brushing your teeth become more difficult and less effective. Additionally, water sources contaminated with lead, such as in the well-known Flint, Michigan crisis, which disproportionately affected a predominantly Black population, pose serious risks to children’s development, including their dental health. Lead exposure has been linked to tooth enamel defects, increased susceptibility to cavities, and periodontitis (gum disease). Similarly, communities that lack fluoride in their drinking water often experience higher rates of tooth decay, especially among children. In Flint, Michigan, persistent campaigns against water fluoridation, despite the community’s critical need for its protective benefits, have contributed to severe oral health disparities, with over 60% of third-grade children exhibiting untreated cavities, fillings, or loss of their first permanent molars, highlighting the intersection of public health misinformation, environmental racism, and structural inequities. Research consistently shows that water fluoridation reduces cavities by 25% in children and adults, yet access remains unequal.

Air pollution

The mouth is one of the first places air pollutants pass through, exposing the gums directly, but there’s still limited research on how this connects to oral health. Air pollution is identified as the leading environmental risk to human health, responsible for roughly one in eight deaths globally, with key culprits including particulate matter (PM2.5), sulphur dioxide (SO₂), nitrogen dioxide (NO₂), and ozone; collectively known as major components of traffic-related air pollution. Fine particulate matter (PM2.5) and nitrogen dioxide (NO₂), both common near highways, industrial corridors, and urban centres, do not only harm the lungs and heart but, also contribute to inflammation and tissue damage in the mouth. A 2024 U.S. national study found that higher PM2.5 exposure was linked to increased incidence of oral cavity and pharyngeal cancers, as well as other head and neck cancers. Similarly, a 2023 cross-sectional study of 42,020 South Koreans found that higher PM10 and ozone levels were linked to increased periodontitis prevalence, while higher humidity and nitrogen dioxide were linked to lower risk, highlighting air pollution as a modifiable factor in oral health and broader public health policy. As with contaminated water, the burden of air pollution is not distributed equally. Toronto has recently faced recurring poor air quality due to smoke from wildfires in Quebec and northeastern Ontario, with levels reaching moderate health risk on the Air Quality Health Index. Research and expert commentary indicate that marginalized communities, including low-income residents, racialized groups, recent immigrants, and those in social housing, are disproportionately exposed to air pollution and have fewer means to protect themselves, increasing their risk for both respiratory and oral health problems. People living in low- and middle-income countries disproportionately experience the burden of outdoor air pollution, with 89% of 4.2 million global premature deaths occurring in these regions, particularly in the WHO South-East Asia and Western Pacific regions. This unequal distribution reflects a pattern of environmental injustice where already marginalized populations carry the heaviest burden of exposure.

Housing hazards

Housing is a critical site where environmental exposures and oral health intersect, yet it is often overlooked in public health discussions. Poorly maintained housing can harbour multiple hazards that directly and indirectly affect oral health. Mold exposure, especially from black mold, can negatively impact children’s oral health. Fungi such as Candida can enter the mouth through the contaminated home environment, sometimes becoming part of dental plaque and contributing to cavities or oral thrush. Living in moldy conditions can irritate the respiratory and mucous membranes, causing children to breathe through their mouths and produce less saliva, which is essential for protecting teeth and gums. Mold-related sinus inflammation can also lead to gum issues, showing that both direct and indirect exposure to mold can increase the risk of dental problems and compromise overall health. Lead-based paint remains a significant concern in older housing stock, particularly in homes built before the 1960s. In older Canadian homes, peeling or damaged lead paint can release toxic dust that harms children’s development and causes serious health effects, with no safe level of exposure. A study of 400 industrial workers found that chronic lead exposure significantly worsened oral health, with higher blood lead levels linked to increased rates of gum disease, tooth decay, and dental erosion. Similarly, a 2025 review of 13 studies involving over 44,000 children found that even low blood lead levels were consistently linked to higher rates of tooth decay and enamel defects, with risk increasing as lead exposure rose. The burden of poor housing conditions falls hardest on low-income and marginalized families, who are more likely to live in poorly maintained buildings with mold, lead, and inadequate ventilation. A 2020 scoping review reveals that indoor air quality is often poorer in lower-income households, where inadequate ventilation and aging infrastructure permit pollutants to accumulate. Addressing mold, lead, and air quality through better maintenance and infrastructure is crucial to breaking cycles of poor health and inequality.

Food deserts & diet-related decay

Finally, diet cannot be ignored. Food deserts-areas with limited access to fresh produce and affordable groceries-push families toward processed, sugar-heavy diets. Sugary beverages and fast foods are well-established drivers of tooth decay. A 2014 study in the U.S. found that children from food-insecure households are more likely to suffer from untreated cavities compared to their food-secure peers. Similar patterns are documented globally, from major cities to rural communities in low- and middle-income countries (LMICs). A 2021 UK–US study found that older adults with poor oral health, such as tooth loss, gum disease, or dry mouth, were more likely to have poor diet quality and consume fewer nutrient-rich foods. Those with persistent poor diets also had a higher risk of oral health problems over time. The findings highlight a two-way relationship: poor nutrition worsens oral health, and poor oral health makes eating healthy foods more difficult. The link between diet and oral health is not simply about individual choices; it reflects structural barriers such as inadequate transportation, food affordability, and the absence of healthy food retailers in marginalized neighbourhoods. Addressing diet-related oral health inequities requires systemic solutions, investing in affordable food programs, urban agriculture, and nutrition education, to make healthy eating accessible to all.

What can we do?

Clean water is a human right, yet not all Canadians have it. Federal commitments to end boil water advisories on reserves have repeatedly been delayed. Immediate investment is needed to upgrade water infrastructure in Indigenous and rural communities, coupled with sustainable operations funding so that systems remain functional. Globally, efforts to expand safe water access must also prioritize fluoridation where feasible, given its proven protective effect against cavities.

Oral health professionals and researchers must advocate for oral health to be explicitly included in environmental health frameworks. Just as air quality is monitored for its impact on asthma, it should also be tracked for its link to periodontal disease. Urban planning and environmental regulations should account for oral health outcomes when evaluating air pollution, housing standards, and industrial zoning. By embedding oral health into environmental policy, governments can prevent disease upstream rather than paying the much higher costs of treatment later.

Addressing food deserts is essential for reducing diet-related tooth decay. Policy solutions include subsidizing grocery stores in under-served neighbourhoods, supporting community gardens, and expanding school meal programs that provide nutritious, low-sugar options. In the long run, tackling food deserts benefits not only oral health but also reduces risks for diabetes, obesity, and cardiovascular disease.

The “so what” is clear: oral health inequities are not just about teeth; they are indicators of deeper injustices. When water systems fail, when air is polluted, and when nutritious food is out of reach, oral health suffers alongside “general” health. Yet unlike lungs or hearts, mouths are rarely part of the environmental justice conversation. This silence has consequences. Poor oral health can affect nutrition, employment opportunities, school performance, and overall quality of life. It reinforces stigma and perpetuates inequality. By re-framing oral health as an environmental justice issue, we shift responsibility away from individuals and toward the systems that shape their daily realities. Clean water, safe housing, and healthy food are not luxuries; they are rights. Protecting oral health requires protecting these rights. As researchers, practitioners, and policymakers, we must broaden our understanding of oral health beyond the dental chair and see it as inseparable from environmental justice. Only then can we build healthier and fairer communities.

Authored: Amisha Parmar