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This study aims to evaluate and compare the effect of fibroblastic growth factor 2 (FGF-2) and photobiomodulation, solely or in combination, in angiogenic differentiation of human periodontal ligament stem cells (hPDLSCs). The study comprises the following groups: control group (hPDLSCs only), FGF-2 (50 ng/mL) group, two photobiomodulation groups with a 4 J/cm 2 energy density of 808 nm diode laser (1-Session or 2-Session), and two groups with the combination of each 1-Session or 2-Session photobiomodulation with FGF-2 (50 ng/mL). The 4',6-diamidino-2-phenylindole (DAPI) staining, and Methyl Thiazolyl Tetrazolium (MTT) assay were undertaken on days 2, 4, and 6. Quantitative Real-time Polymerase Chain Reaction (RT-qPCR) analysis on days 2, 4, 6, 8, and 11 was conducted to investigate VEGF-A and ANG-I genes. Coherently, the results of the DAPI and MTT showed the Laser (2-Session) group had higher cell viability than others on day 6. All groups demonstrated a growth pattern in the expression of VEGF-A and ANG-I from day 2 to 8 and, afterward, a significant downgrowth to day 11 (p < 0.05). The most amounts of expression of VEGF-A and ANG-I on day 8 were seen in the Laser (2-Session) group. Two-time application of photobiomodulation using a diode laser with 808 nm wavelength after 2 and 4 days of cell seeding can be associated with higher cell viability and angiogenic differentiation of hPDLSCs compared to the one-time application of photobiomodulation and administration of FGF-2., (© 2024 American Society for Photobiology.)

To evaluate the impact of photobiomodulation therapy (PBMT) on injection pain perception and compare it with a topical oral anesthetic gel. A total of 30 patients of 6 to 9 years-old seeking pulpotomy treatment of maxillary secondary primary molars of both sides were considered for this split-mouth triple-blind randomized clinical trial. On one side of the maxilla, the low-level laser (diode laser, 808 nm, 250 mW; 16.25 J; 32.5 J cm -2 ) was irradiated upon the buccal gingiva of the tooth, while a Benzocaine 20% topical anesthetic gel was applied on the other side. A gel with the same taste (strawberry) was applied for the placebo. The Wong-Baker Faces Pain Rating Scale was used to evaluate the injection pain and postoperation pain at two timestamps, 1 h and 24 h after treatment. Patients' heart rate was also evaluated. Paired t, Wilcoxon signed-rank test, McNemar and Friedman tests were used for statistical analyses. Results demonstrated that PBMT could significantly decrease the injection pain perception and heart rate alternations compared to the topical anesthetic gels (P = 0.000). However, no significant differences were documented between the two methods concerning the 1-h (P = 0.26) and 24-h (P = 1.00) postoperation pain. PBMT can be an effective nonpharmacological technique for controlling injection pain., (© 2022 American Society for Photobiology.)

Rapid maxillary expansion (RME) is performed on transversely deficient maxilla. As all orthodontic treatments, retention is important in maintaining therapeutic outcomes. Fixed /removable retainers are used post-RME causing hygiene and compliance problems. Given photobiomodulation's positive effects on the quantity and quality of bone regeneration, its effect on post-RME relapse was studied. Thirty Sprague Dawley rats were randomly divided into group R, non-irradiated RME-treated (n = 12), group P, irradiated RME-treated (n = 12) and group C, non-RME non-irradiated (n = 6). A 1.5 mm metal ring inserted between maxillary incisors at days 0 and 15 was expanded until 1.5 mm space was obtained at day 30. In group P, Ga-Al-As diode laser (810 nm, 100 mW, 4J/cm 2 , 30 secs) was applied on days 0, 2, 4, 6, 8, 10, 12 and 14 as predictor variable. The relapse was measured as the space lost between incisors for 30 days after appliance removal (primary outcome variable) and compared with t-test. In week 2, space loss in group P was significantly lower (P < 0.05) than all other groups. The relapse during weeks 2 and 3 was significantly lower in group P than group R. However, no significant difference in relapse amount was found between groups during first and fourth week. There was a significant difference (P < 0.05) between groups in relapse rates (secondary outcome variable) but not in total relapse after 4 weeks. Photobiomodulation proved beneficial in resisting relapse in our study, and it is suggested to be continued until the end of expansion., (© 2020 American Society for Photobiology.)