Air pollution can damage oral tissues and increase the risk of tooth loss by accelerating bone destruction, according to researchers from the University of Sao Paulo.
The study, published in the peer-reviewed journal Air Quality, Atmosphere and Health, examined the biological impact of fine particulate matter known as PM2.5. Scientists conducted laboratory experiments by exposing mice to polluted air collected directly from a district in Sao Paulo, Brazil.
PM2.5 consists of microscopic airborne particles measuring 2.5 micrometres or smaller in diameter, primarily produced by vehicle exhausts and industrial emissions. Due to their tiny size, these fine particulates easily float in urban air and penetrate biological barriers.
The experiment revealed that PM2.5 exposure intensified inflammation in the tissues surrounding the teeth and accelerated the loss of alveolar bone, which holds tooth roots in the jaw. Breakdown of alveolar bone is a primary hallmark of periodontitis, a severe gum disease that is a leading cause of tooth loss in adults.
Damage to tongue tissue
Researchers also identified unexpected structural changes on the tongue mucosa of the test animals. Even in mice without artificially induced gum inflammation, exposure to polluted air caused the protective outer layer of the tongue to thicken significantly.
The tongue tissues showed increased deposits of keratin, a fibrous structural protein, along with a higher count of activated mast cells, which are immune cells that drive inflammatory responses. Simultaneously, levels of inflammatory signaling molecules rose and oxidative stress intensified across both tongue and periodontal tissues.
Oxidative stress is a chemical imbalance where toxic reactive molecules overload cellular antioxidant defenses, leading to tissue damage. Activated mast cells similarly release chemical signals that sustain chronic inflammation in affected tissues.
Pathways of air pollution damage
The authors of the study explained that airborne pollution particles can harm the oral cavity through two distinct biological pathways. In the first mechanism, fine particles make direct contact with the oral mucosa during normal breathing.
In the second mechanism, inhaled particles travel deep into the lungs and trigger systemic inflammation that spreads through the bloodstream to affect distant tissues across the body.
The findings add to growing scientific concern over the widespread health impacts of urban air pollution. Previous research has shown that exposure to fine particulate pollution can also accelerate brain aging and impair cognitive health.
The University of Sao Paulo is Brazil's largest public university and a major center for scientific research in South America. Air Quality, Atmosphere and Health is an international journal that covers environmental chemistry, atmospheric science, and human health effects.
