Purpose: To investigate the effect of low-energy microwave irradiation on the movement of orthodontic teeth and periodontal tissue reconstruction in rats.
Methods: SD rats were randomly divided into control group and experimental group. Helical spring force method was used to construct a rat orthodontic model through a nickel-titanium tension spring device. Rats in the experimental group were irradiated with a microwave treatment apparatus once a day to move the first molars for 30 minutes, while rats in the control group were not given any intervention. The rats were sacrificed on the day of modeling, 7 d, 14 d, and 21 d thereafter. The movement distance of the rat's first molars was measured. Tartrate-resistant acid phosphatase (TRAP) staining was used to detect osteoclast counts in rat periodontal tissues, immunohistochemistry was used to detect the expression of cell differentiation factor (osteoclast differentiation factor, ODF) in rat periodontal tissues; real-time fluorescence quantitative PCR(RT-PCR) was used to detect the mRNA expression of interleukin 6(IL-6) and tumor necrosis factor-α (TNF-α). SPSS 20.0 software package was used to analyze the experimental data.
Results: At 7, 14, 21 d, compared with the control group, the distance of the first molar movement, the count of osteoclasts in the periodontal tissue, and the expression of ODF in the experimental group were significantly increased (P＜0.05), while the mRNA expression of IL-6 and TNF-α in periodontal tissues was significantly decreased (P＜0.05).
Conclusions: Low-energy microwave irradiation can significantly accelerate the movement of orthodontic teeth, inhibit the expression of inflammatory genes, and promote the reconstruction of periodontal tissue.