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Understanding Oral Hygiene and Periodontal Health in Space Using a Bedrest Analog Model for Weightlessness (NASA
Sonja Henny Maria Derman1, Laura de Boni2,3,4, Edwin Mulder2
1Faculty of Medicine and University Hospital Cologne, Polyclinic for Operative Dentistry and Periodontology, University of Cologne, Cologne, Germany.
Clinical and Experimental Dental Research
|July 16, 2026
Summary
Head-down tilt bed rest worsens oral hygiene and gingival inflammation due to impaired plaque control, not salivary changes. This highlights the need for better oral care strategies during space missions.
Area of Science:
- Space medicine
- Oral health research
- Physiology
Background:
- Microgravity simulations are crucial for understanding physiological changes during spaceflight.
- Head-down tilt bed rest (HDTBR) is a validated analog for microgravity effects.
- Oral health can be affected by altered physiological conditions.
Purpose of the Study:
- To assess changes in oral hygiene, gingival inflammation, and salivary secretion during a 60-day HDTBR protocol.
- To evaluate the impact of simulated microgravity on oral health parameters.
- To identify potential biomarkers for adaptation to unloading conditions.
Main Methods:
- Twenty-four healthy volunteers underwent a 60-day, 6° HDTBR protocol.
- Oral health assessments were conducted at baseline, mid-study, end-study, and post-recovery.
- Evaluated plaque accumulation, gingival inflammation, bleeding on probing, and salivary flow rate.
Main Results:
- Significant increases in plaque accumulation (Quigley-Hein Plaque Index) and gingival inflammation (Gingival Index, bleeding on probing) were observed.
- Gingival inflammation markers showed partial recovery post-HDTBR, but remained elevated.
- Unstimulated salivary flow rate remained unchanged throughout the study.
Conclusions:
- Prolonged gravitational unloading leads to plaque-driven gingival health deterioration.
- Impaired mechanical plaque control and microcirculatory changes, rather than salivary dysfunction, are likely causes.
- Gingival tissues serve as sensitive biomarkers for unloading adaptation, emphasizing the need for optimized oral hygiene during space missions.
