Plaque in orbit: Gum disease gets worse in space

Space may feel weightless, but its effect on oral health can be heavy. A new animal study shows that near-weightlessness speeds up gum disease – the kind that eats away at bone and can eventually cause teeth to fall out.

Researchers from the University of Sharjah published these findings after using a lab setup to mimic space conditions. They placed mice in a simulated microgravity environment and compared the results with a group that remained under normal gravity on Earth.

Simulating space without leaving Earth

To create these conditions, the team used a “hind-limb unloading” model. It’s a common method for simulating microgravity in rodents.

The researchers placed the mice in tilted positions to remove weight from their back legs. Meanwhile, gum disease was induced placing ligatures around their molars.

“Six male C57BL/6J mice (3–4 months, ~30 g) were randomly divided into two groups (n=3 each): (a) ground control with ligature-induced periodontitis and (b) hindlimb unloaded with ligature-induced periodontitis,” explained the study authors.

“All procedures followed ethical approval (ACUC-02-02-2023). Mice were anesthetized (100 mg/kg ketamine/5–10 mg/kg xylazine, intraperitoneally) prior to ligature placement between the first and second left maxillary molars.”

Gum disease in space

The changes were clear. “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 Zahi Badran, a professor of periodontology at the University of Sharjah.

“They had higher levels of disease markers, more severe tissue damage, and more immune cells in the affected areas.”

Additionally, the microgravity group exhibited a marked increase in CEJ-ABC distance, indicating significant bone resorption.

They also showed elevated levels of alkaline phosphatase activity (ALP), a common marker of bone turnover, further suggesting heightened inflammation and accelerated bone loss linked to altered gravity.

Beyond oral health

While the experiment focused on gum disease in space, the implications stretch further. “It also opens the door to better understanding how inflammation works in the body, both in space and on Earth,” said Dr. Badran.

The authors also note that researchers have largely overlooked oral health in space. “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,” they wrote.

Planning for the next space frontier

This research is especially timely as plans for longer space missions – such as journeys to Mars – move closer to reality.

Dr. Badran said the study highlights the importance of rethinking astronaut health protocols. “This calls for the integration of dental medicine, particularly periodontology, into astronaut/future space colonies’ inhabitants’ health protocols,” he noted.

Specialized prevention and treatment strategies, along with in-mission monitoring tools, most probably will be essential in case of prolonged space stays.

Simultaneously, the model offers terrestrial benefits, providing insights into the periodontal status of immobilized bed patients, who experience similar effects of microgravity.

This model will be extensively studied to better understand the biological pathways underlying these outcomes. Researchers will also explore how periodontitis may influence other systemic diseases under microgravity.

Future research directions

Although the study involved a small sample of six mice, the researchers believe it’s a strong start. They plan to expand the model and continue a new line of research on oral health and disease in microgravity. This work will shed more light on space medicine in general.

The experts also aim to study links between gum and systemic diseases in space by assessing more microbiological and immune factors in microgravity.

Future investigations may explore how prolonged space travel affects oral microbiomes, immune response, and tissue regeneration. Such insights could lead to the development of targeted countermeasures to protect astronauts on long-duration missions.

Space missions may be cutting-edge, but without proper dental care, astronauts could end up paying for it in plaque and pain. This study is a reminder that when it comes to space travel, even your gums aren’t immune to gravity – or the lack of it.

The full study was published in the Journal of Periodontal Research.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–