Dynamic Imaging of Human Gingival Blood Flow After Transient Clamping

Objectives: Laser Speckle Contrast Imager (LSCI) is a high resolution optical imaging device, suitable for studying changes in microcirculation. In the present study LSCI was used to map spatial and temporal changes in gingival blood flow after short-term occlusion.
Methods: Horizontal, vertical, and papilla base incisions were modelled by performing clamping of the attached gingiva in 21 healthy patients (13 women and 8 men). LSCI was applied to determine the dynamic changes of the regional blood flow during five-second interval of occlusion and subsequently for twenty minutes. Statistical analysis of the data was carried out by Mixed Model approach.
Results: Resting blood flow in the attached gingiva apically to the papillae was higher as compared to that in the midbuccal area of the teeth in both genders (p <0.001). During short-term horizontal occlusion ischemia was greater coronally than apically to the occlusion line (p <0.001). There was no significant difference in the blood flow reduction nor mesial or distal to the vertical occlusion line, neither coronal or apical to the papilla based occlusion line. Post-occlusive hyperaemia was observed not only in the regions affected by the ischemia, but encompassed wider area (p <0.05). Hyperaemic response was more expressive and prolonged in male than in female (p <0.05).
Conclusions: Blood flow in the attached gingiva is highly heterogeneous. In addition, applying horizontal occlusion our findings reinforce the apico-coronal orientation of blood circulation described in the literature. Hyperaemia after transient occlusion covers wider area than ischemia itself, probably due to vasoactive reflexes. Gender difference in response to transient ischemia is a new observation, however, its importance and explanation needs further investigation.