Air pollution could damage tissues inside the mouth and make gum disease worse, according to new research by scientists in Brazil.
Researchers from São Paulo State University (UNESP) and the University of São Paulo (USP) found that exposure to PM2.5 increased inflammation, oxidative stress and damage to the tissues that support teeth in experiments involving mice.
For the study, mice were exposed to polluted air collected around Doutor Arnaldo Avenue in São Paulo, in a controlled setting. The researchers found that exposure to PM2.5 worsened inflammation in the tissues around the teeth and increased the loss of alveolar bone which helps hold teeth in place.
Loss of this bone is a key feature of periodontitis, a common inflammatory gum disease that can damage the tissues supporting the teeth and eventually lead to tooth loss.
However, some of the most significant findings were seen in the tissue covering the tongue.
The researchers found changes in the oral mucosa, including a thicker layer of tissue, increased deposits of keratin and a higher number of activated mast cells. These cells are involved in the body’s immune and inflammatory responses.
Importantly, these changes were seen even in mice that did not have artificially induced gum inflammation, suggesting that the lining of the mouth itself could be particularly sensitive to air pollution.
Luis Carlos Spolidorio, professor at UNESP’s School of Dentistry and coordinator of the study, said: ‘It’s already well documented that pollution affects various organs. Since the oral cavity is constantly exposed to the external environment, we suspected that it might also be affected by pollution. What we didn’t expect to observe were such significant changes in oral tissues.’
The study also found increased levels of inflammatory markers and signs of oxidative stress in both the tongue and tissues surrounding the teeth.
Oxidative stress occurs when harmful reactive molecules build up faster than the body’s antioxidant defences can deal with them. This can damage cells and tissues and may contribute to inflammation.
The researchers believe pollution could affect the mouth in several ways. Polluting particles can come into direct contact with the oral tissues, potentially triggering local inflammation. They may also cause inflammation and oxidative stress after reaching the lungs, with effects that spread to other parts of the body.
Spolidorio said: ‘We’ve demonstrated in a controlled experimental setting that the oral mucosa undergoes changes when exposed to fine particulate matter. This finding represents an important advance since previous studies were limited to identifying correlations between air pollution and oral diseases. With our study, we were able to elucidate the cellular and molecular mechanisms linking exposure to the pollutant to the changes observed in the oral cavity.’
The full research can be read here.
Photo: Quang Tri NGUYEN
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