Site‐Resolved Gingival Microcirculation and Colour Features in Health and Early Inflammation

ABSTRACT Aim To characterise site‐level gingival microcirculation in health and early inflammation without clinical attachment loss (CAL), and to evaluate its relationship with probing‐derived clinical parameters and scan‐derived gingival colour metrics. Materials and Methods In this cross‐sectional observational study, gingival microcirculation was assessed at five maxillary anterior interdental papillae and matched keratinised gingival (KG) sites using a combined laser Doppler flowmetry and tissue spectrophotometry system (O2C), providing oxygen saturation (SO 2 ), relative haemoglobin (Hb) and blood flow (Flow). Gingival papilla colour was extracted from intraoral scans and converted to CIE L * a * b * metrics. The primary analysis was restricted to sites without clinical attachment loss (CAL = 0 mm), with BOP used as a site‐level indicator of gingival inflammation. Site comparisons, correlations and mixed‐effects models were performed. Results Seventy‐four young adults were included. Three‐hundred and forty‐six papilla sites and their matched KG sites were analysed. KG sites showed higher SO 2 , Hb and Flow than papilla sites. Papilla microcirculation showed substantial heterogeneity, with both between‐participant and within‐participant/site‐level variance components. Clinical alignment was limited: papillary Hb was associated with probing depth (PD) and bleeding on probing (BOP), whereas Flow showed weaker associations and SO 2 showed no significant association. In mixed‐effects models, conventional clinical indices accounted for only a small proportion of the variance in papillary microcirculation. Among colour metrics, lightness ( L *) showed the clearest clinical pattern, being inversely associated with BOP, PD and papillary Hb. Conclusions In early gingival inflammation, papillary microcirculation is a measurable and heterogeneous site‐level feature that is only partly captured by routine probing‐derived parameters. Scan‐derived gingival colour, particularly lightness, provides complementary information on local inflammatory status. Additional studies are needed to properly characterise microcirculation and tissue colour across the full health–disease spectrum.