Department of Stomatology, Jiangdu People's Hospital Affiliated to Yangzhou University, Yangzhou, 225200, China.
Department of Stomatology, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, 030032, China.
BMC Oral Health. 2024 Sep 29;24(1):1155. doi: 10.1186/s12903-024-04943-x.
Shortening retention time and minimizing relapse rates are ongoing challenges in orthodontics. This study investigated the effects of natural fulvic acids (FAs) and low-level laser therapy (LLLT) on orthodontic retention in rats.
Seventy-two male Sprague-Dawley rats underwent mesial movement of the left maxillary first molar using a 50 g force via a nickel-titanium tension spring. After three weeks of movement, the rats entered the retention phase with retainer wires and were divided into four groups: Control (no intervention), FAs (80 mg/kg orally daily), LLLT (808 nm laser twice weekly), and FAs + LLLT (both treatments). Retainers were removed on days 7, 14, and 21 for a 3-day relapse assessment. Maxillary impressions were analyzed for relapse rates using 3Shape software, alongside histological and immunohistochemical evaluations of bone morphogenetic protein-2 (BMP-2) expression in periodontal tissues, with differences among groups analyzed using an ordinary two-way analysis of variance (ANOVA).
The relapse rate decreased over time, particularly at 10, 17, and 24 days (p < 0.001). The FAs group did not significantly affect relapse rates compared to the control group (p = 0.084). In contrast, both the LLLT and FAs + LLLT groups significantly reduced relapse rate (p < 0.001), with no significant difference between these groups (p = 0.555). Histological examination revealed active osteoclasts on day 10, decreasing by days 17 and 24. The LLLT and FAs + LLLT groups showed less local cementum resorption and better periodontal fiber arrangement. All treatment groups significantly increased BMP-2 expression (P < 0.05) compared to controls. with LLLT and FAs + LLLT differing significantly from FAs (P < 0.001), though no difference was observed between LLLT and FAs + LLLT (P = 0.578).
FAs did not significantly reduce relapse rate with retainers, while LLLT effectively reduced relapse rates, showing no additional benefit from combining FAs with LLLT. Both FAs and LLLT increased BMP-2 expression in PDL fibroblasts but with no synergistic effect.
缩短保持时间和最小化复发率是正畸学的持续挑战。本研究探讨了天然富里酸（FA）和低水平激光疗法（LLLT）对大鼠正畸保持的影响。
72 只雄性 Sprague-Dawley 大鼠通过镍钛张力弹簧施加 50g 力进行左侧上颌第一磨牙近中移动。移动 3 周后，大鼠进入保持阶段，用保持器丝，分为 4 组：对照组（无干预）、FA（每天 80mg/kg 口服）、LLLT（808nm 激光每周 2 次）和 FA+LLLT（两种治疗方法）。在 3 天的复发评估中，第 7、14 和 21 天去除保持器。使用 3Shape 软件对上颌模型进行复发率分析，并对牙周组织中骨形态发生蛋白-2（BMP-2）表达进行组织学和免疫组织化学评价，使用普通双向方差分析（ANOVA）分析组间差异。
复发率随时间降低，尤其是在 10、17 和 24 天（p<0.001）。FA 组与对照组相比，复发率无显著差异（p=0.084）。相比之下，LLLT 和 FA+LLLT 组均显著降低了复发率（p<0.001），但组间无显著差异（p=0.555）。组织学检查显示第 10 天有活跃的破骨细胞，第 17 和 24 天减少。LLLT 和 FA+LLLT 组显示局部牙骨质吸收较少，牙周纤维排列较好。与对照组相比，所有治疗组的 BMP-2 表达均显著增加（P<0.05），LLLT 和 FA+LLLT 与 FA 组之间存在显著差异（P<0.001），但 LLLT 和 FA+LLLT 之间无差异（P=0.578）。
FA 对带保持器的复发率无显著降低作用，而 LLLT 可有效降低复发率，FA 联合 LLLT 无额外获益。FA 和 LLLT 均增加了牙周膜成纤维细胞中 BMP-2 的表达，但无协同作用。
