The periodontium contains an extensive blood supply, and periodontitis is known to trigger harmful structural and functional vascular alterations. In contrast, the influence of minor oral inflammation—levels commonly seen in many otherwise healthy people—on cardiovascular physiology remains uncertain. This preliminary investigation aims to assess how an objectively quantified whole-mouth oral inflammatory load (OIL) relates to vascular function in individuals without known health issues. In this cross-sectional, correlational project, 28 adults aged 18–30 years (16 men, 12 women) with no systemic conditions were enrolled. Oral neutrophil counts, a validated metric for OIL, were obtained from 30-s mouth-rinse samples. Participants also underwent measurements of blood pressure, arterial stiffness via pulse-wave velocity, and endothelial function using brachial artery flow-mediated dilation. Oral neutrophil count was the only factor that significantly explained variation in flow-mediated dilation % (p = 0.04; R² = 0.16; β = −1.05). Individuals exhibiting OIL values corresponding to >2.5 × 10⁵ neutrophils (n = 8) demonstrated reduced flow-mediated dilation (6.0 ± 2.3%) compared with participants whose counts reflected gingival health (<2.5 × 10⁵ neutrophils: 10.0 ± 5.2%, p = 0.05). No meaningful predictors were identified for arterial stiffness. Higher OIL levels were associated with diminished flow-mediated dilation. Compromised flow-mediated dilation is recognized as an early warning sign for later cardiovascular disease—one of the predominant causes of mortality in North America. These findings emphasize the relevance of oral health and suggest that OIL may influence endothelial function.
