The Effect of Acute High-Altitude Exposure on Oral Pathogenic Bacteria and Salivary Oxi-Inflammatory Markers

<b>Background:</b> The environment can alter the homeostasis of humans and human microbiota. Oral health is influenced by high altitude through symptoms of periodontitis, barodontalgia, dental barotrauma, and a decrease in salivary flow. Microbiota and inflammatory state are connected in the oral cavity. This study aimed to explore the effect of acute high-altitude exposure on the salivary microbiome and inflammatory indicators. <b>Methods:</b> Fifteen healthy expeditioners were subjected to oral examination, recording the plaque index (PII), gingival index (GI), the simplified oral hygiene index (OHI-S), and the number of teeth; unstimulated saliva samples were collected at an altitude of 1191 m (T1) and 4556 m (T2). TNF-α, sICAM1, ROS, and the oral bacterial species <i>Porphyromonas gingivalis</i> (<i>Pg</i>) and <i>Fusobacterium nucleatum</i> (<i>Fn</i>) were quantified. <b>Results:</b> At T2, slCAM, TNF, and ROS increased by 85.5% (IQR 74%), 84% (IQR 409.25%), and 53.5% (IQR 68%), respectively, while <i>Pg</i> decreased by 92.43% (IQR 102.5%). The decrease in <i>Pg</i> was greater in the presence of low OHI-S. The increase in slCAM1 correlated with the reduction in <i>Fn</i>. Individuals with high GI and OHI-S had a limited increase in TNF-α at T2. <b>Conclusion:</b> Short-term exposures can affect the concentration of pathogenic periodontal bacteria and promote local inflammation.