Space conditions can lead to periodontitis, scientists say

A new study shows that living in zero gravity can lead to periodontitis — a common and serious condition where the gums become inflamed and the bone that supports teeth starts to break down, eventually leading to tooth loss.

In the study published in the Journal of Periodontal Research, scientists from the University of Sharjah sought to understand how simulated microgravity — the near-weightless environment astronauts experience in space — might influence the development and severity of periodontitis. They carried out their experiment with mice in the lab — the mice were placed in a position that mimics the effects of microgravity, and then gum disease was induced.

“Mice exposed to simulated microgravity showed much worse gum inflammation and bone loss compared to mice with induced periodontitis on the ground,” said lead author Professor Zahi Badran. “They had higher levels of disease markers, more severe tissue damage, and more immune cells in the affected areas.”

The mice on the ground were found to show minimal bone loss, while the group in simulated space conditions exhibited a marked increase in CEJ-ABC distance, indicating significant bone resorption. The group in simulated space fight also displayed a significant increase in alkaline phosphatase (ALP) activity compared to the control group, indicating increased bone resorption and inflammation associated with periodontitis due to the change in gravity.

The research indicates that microgravity can exacerbate induced gum disease in animals, underscoring the importance of developing tailored dental prophylaxis and care strategies for future space explorers. “It also opens the door to better understanding how inflammation works in the body, both in space and on Earth,” Badran said.

As longer space missions become a real possibility, scientists are looking more closely at how space conditions affect human health. However, the authors maintain that one area that’s been less studied is oral health and diseases in microgravity, especially gum disease.

“To the best of our knowledge, this is the first in vivo pilot study to investigate microgravity’s effects on periodontitis progression using the combination of the hindlimb unloading (HLU) model in mice with the ligature-induced periodontitis (LIP) model,” the authors said. The study thus calls for the integration of dental medicine into astronaut/future space colony inhabitants’ health protocols, Badran said.

“Specialised prevention and treatment strategies, along with in-mission monitoring tools, most probably will be essential in case of prolonged space stays,” he said. “Simultaneously, the model offers terrestrial benefits, providing insights into the periodontal status of immobilised bed patients, who experience similar effects of microgravity.”

The authors acknowledged the limitations of their study, including the small sample size of only six mice as well as the use of the HLU model (which offers insights into disease progression under space-like conditions but does not account for two key environmental stressors encountered in actual spaceflight: ionising radiation and hypoxia). They suggested that, in future studies, integrating the HLU model with additional stressors such as radiation exposure or hypoxic conditions could provide a more comprehensive understanding of spaceflight-associated pathophysiology. They also plan to replicate their model to assess additional microbiological and immunological parameters to investigate the connection between gum diseases and other systemic diseases in microgravity.

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