Mortazavi Zadeh Erfan, Mirhashemi Amirhossein, Pourhajibagher Maryam, Ghorbani Mahsa, Shafaee Hooman, Tanbakuchi Behrad
Dentist, Private practice, Tehran, Iran.
Department of Orthodontics, School ofDentistry, Tehran University of Medical Sciences, Tehran, Iran.
Lasers Med Sci. 2025 Sep 16;40(1):360. doi: 10.1007/s10103-025-04560-2.
The aim of this study was to evaluate the efficacy of antimicrobial photodynamic therapy (aPDT) using toluidine blue (TBO) activated by a diode laser and zinc oxide (ZnO) activated by light-emitting diode (LED) light in reducing bacterial accumulation on polymethyl methacrylate (PMMA) orthodontic appliances.
This in-vitro study investigated the formation of Streptococcus mutans biofilm on 32 PMMA resin discs, divided into four groups. The first group consisted of acrylic discs containing ZnO exposed to 450 nm LED radiation; the second group included acrylic discs with TBO and 635 nm diode laser radiation; the third group was the positive control with chlorhexidine (CHX); and the fourth group served as the negative control. To evaluate biofilm formation, the discs were immersed in tubes containing a microbial suspension at a 0.5 McFarland concentration. Following incubation, the discs were exposed to light according to the type of photosensitizer. After washing with saline and sonication, bacterial colony counts were determined by serial dilution and culture in Brian Heart Infusion agar medium. One-way ANOVA was used to compare the colony-forming unit (CFU) counts, and post-hoc Tamhane's test was performed for pairwise comparisons, with statistical significance set at p < 0.05.
The negative control group exhibited the highest mean colony count (35.72 ± 3.35 CFU/mL), while the positive control group showed the lowest mean colony count (5.87 ± 0.92 CFU/mL). Both ZnO and TBO groups, when activated by their respective light sources, demonstrated significant antibacterial activity compared to the negative control (P < 0.001 for both). However, CHX outperformed both ZnO and TBO in reducing bacterial growth (P < 0.001 and P = 0.007, respectively). No statistically significant difference was observed between the antibacterial effects of ZnO and TBO (P = 0.280).
This study suggests that aPDT using ZnO and TBO can be an effective adjunctive treatment for reducing bacterial accumulation on orthodontic appliances. While CHX remains the most effective treatment, the cost-effectiveness and ease of application of both CHX and ZnO make them viable options for future clinical trials. Further research is needed to optimize treatment protocols and explore the potential impact of these treatments on other microorganisms and material properties.
本研究旨在评估使用二极管激光激活的甲苯胺蓝（TBO）和发光二极管（LED）光激活的氧化锌（ZnO）进行抗菌光动力疗法（aPDT）在减少聚甲基丙烯酸甲酯（PMMA）正畸矫治器上细菌积聚方面的疗效。
这项体外研究调查了32个PMMA树脂圆盘上变形链球菌生物膜的形成情况，将其分为四组。第一组由含有ZnO并暴露于450nm LED辐射的丙烯酸圆盘组成；第二组包括含有TBO并接受635nm二极管激光辐射的丙烯酸圆盘；第三组是使用氯己定（CHX）的阳性对照组；第四组作为阴性对照组。为评估生物膜的形成，将圆盘浸入含有0.5麦氏浓度微生物悬液的试管中。孵育后，根据光敏剂类型对圆盘进行光照。用生理盐水冲洗并超声处理后，通过系列稀释和在脑心浸液琼脂培养基中培养来确定细菌菌落计数。采用单因素方差分析比较菌落形成单位（CFU）计数，并进行事后的Tamhanes检验进行两两比较，设定统计学显著性为p < 0.05。
阴性对照组的平均菌落计数最高（35.72±3.35 CFU/mL），而阳性对照组的平均菌落计数最低（5.87±0.92 CFU/mL）。ZnO组和TBO组在各自光源激活下，与阴性对照组相比均表现出显著的抗菌活性（两者P均<0.001）。然而，在减少细菌生长方面，CHX的效果优于ZnO和TBO（分别为P < 0.001和P = 0.007）。ZnO和TBO的抗菌效果之间未观察到统计学显著差异（P = 0.280）。
本研究表明，使用ZnO和TBO的aPDT可以作为减少正畸矫治器上细菌积聚的一种有效辅助治疗方法。虽然CHX仍然是最有效的治疗方法，但CHX和ZnO的成本效益和应用便利性使其成为未来临床试验的可行选择。需要进一步研究来优化治疗方案，并探索这些治疗方法对其他微生物和材料性能的潜在影响。
