Assessment of gingival blood flow changes due to orthodontic force using laser speckle contrast imaging: A randomized controlled trial

Abstract

Background This study aimed to measure gingival blood flow under different orthodontic forces using laser speckle contrast imaging (LSCI). Methods Forty eligible individuals were recruited and randomly assigned into two groups:50 g group and 150 g group. According to the groups, forces of 50 g or 150 g were applied from the maxillary canines to the first molars on the left or right sides of each participant. The canine area's blood flow (regions of interest (ROIs) 1, 2, 3, and 4) was measured using LSCI at different time intervals (baseline, 30 minutes, 1, 3, 7, and 14 days). Results Evaluation of blood flow between the groups revealed significant differences at ROI 1 at 1 day and 3 days; and at ROI 4 at 1 day and 3 days. Intra-group comparisons showed significant differences in blood flow within each group for each region at each time point (P<0.05). After applying orthodontic forces, blood flow reached its nadir within 30 minutes to 1 day. The 150 g group exhibited a more significant decrease compared to the 50 g group. Blood flow peaked at 3 days in the 50 g group and at 7 days in the 150 g group. Both groups finally returned to baseline at day 14. In the resting state without force loading, statistically significant differences in blood flow were observed among the marginal gingiva, attached gingiva, and interdental papilla. The marginal gingiva exhibited lower blood flow compared to other regions. Conclusions Laser speckle contrast imaging is a reliable tool for monitoring gingival blood flow in orthodontic treatment. Gingival blood flow decreased after force application, reaching peak values in 3 to 7 days and eventually returning to baseline within 14 days. Trial registration The trial was registered in Chinese Clinical Trial Registry (ChiCTR2400082438) on 29/03/2024.