Assessment of the test-retest reliability of human gingival blood flow measurements by Laser Speckle Contrast Imaging in a healthy cohort.

ABSTRACT

OBJECTIVE: The reliability of gingival blood flow measured by Laser Speckle Contrast Imaging is unknown. Our aim was to investigate the effect of factors inherent in oral mucosa measurement on intra-day and inter-day reliability. METHODS: Gingival blood flow was measured in seventy healthy subjects. First, measurements were obtained by varying the incidence angle of imaging, using a lip retractor. Second, 3 snapshots were taken with closure of the mouth in-between, and lips were retracted by a dental mirror. These were repeated 1 week later. Third, snapshots were taken either by direct view or using a mirror. Reliability was assessed based on coefficient of variation. RESULTS: Unlike retraction of the lips and the mirror, the incidence angle had an effect on mean blood flow. The coefficient of variation within a subject was 6.4% with the mouth constantly open. With retraction, the intra-session, and the inter-day coefficient of variation were 8.3% and 10.5%, respectively. The coefficient of variation was 11.9% by alternating direct and indirect imaging. CONCLUSIONS: Laser Speckle Contrast Imaging has good short- and long-term reliability regardless of lip retraction or an indirect view. This technique seems to be appropriate for the long-term clinical non-invasive follow-up of gingival microcirculation.