Department of Conservative Dentistry, Friedrich Schiller University Jena, Germany.
Arch Oral Biol. 2011 Mar;56(3):264-8. doi: 10.1016/j.archoralbio.2010.10.007. Epub 2010 Oct 30.
The photodynamic therapy (PDT) is an alternative method to suppress oral pathogens by the activation of a photosensitizer with laser light. The aim of this study was to investigate the phototoxic effect of three ruthenium-based photosensitizers on Fusobacterium nucleatum and Porphyromonas gingivalis.
In this in vitro study F. nucleatum and P. gingivalis were incubated with three photosensitizers: (i) a hydrophobic tris-(4,7-diphenyl-1,10-phenanthroline)-ruthenium(II)-dication (RD3), (ii) a hydrophilic tris-[(1,10-phenanthroline-4,7-diyl)-bis-(benzenesulfonato)]-ruthenate tetra-anion (RSD3) and (iii) a lower hydrophilic tris-(2,2'-bipyridine)-ruthenium(II) dication (RBY). The subsequent irradiation was done with blue-band halogen light (450-485nm) for 20s using a conventional polymerizer. Control samples consisted of bacterial cell suspension irradiated and non-irradiated in the absence of photosensitizer or incubated with the photosensitizer without irradiation. Bacterial inactivation was determined by the numbers of colony-forming units (cfu/ml) after anaerobic cultivation.
The RD3 photosensitizer reduced the viability of F. nucleatum by 4-log10 and of P. gingivalis completely after irradiation for 20s. The viability loss correlated significantly with the concentration of the RD3 photosensitizer and reached a peak at a concentration of 12.5μM (p<0.05). The RSD3 and RBY photosensitizers had distinctly lower phototoxic effects in comparison to RD3.
The RD3 photosensitizer showed a phototoxic effect on F. nucleatum and P. gingivalis. The results suggest that the application of the RD3 photosensitizer under visible light may be helpful as an adjunct treatment approach to the inactivation of periodontopathogenic bacteria.
光动力疗法（PDT）是通过激光激活光敏剂来抑制口腔病原体的一种替代方法。本研究旨在研究三种钌基光敏剂对核梭杆菌和牙龈卟啉单胞菌的光毒性作用。
在这项体外研究中，将核梭杆菌和牙龈卟啉单胞菌与三种光敏剂孵育：（i）疏水性三（4,7-二苯基-1,10-菲咯啉）-钌（II）二阳离子（RD3），（ii）亲水性三[（1,10-菲咯啉-4,7-二基）-双（苯磺酸盐）] -钌酸四阴离子（RSD3）和（iii）低亲水性三（2,2'-联吡啶）-钌（II）二阳离子（RBY）。随后用常规光聚合器在 450-485nm 的蓝光下照射 20s。对照样品由在不存在光敏剂的情况下照射和未照射的细菌细胞悬浮液以及在没有照射的情况下孵育光敏剂组成。通过厌氧培养后形成的菌落形成单位（cfu/ml）的数量来确定细菌失活。
RD3 光敏剂在照射 20s 后可使核梭杆菌的活力降低 4 个对数，使牙龈卟啉单胞菌完全失活。活力损失与 RD3 光敏剂的浓度显着相关，在浓度为 12.5μM 时达到峰值（p<0.05）。与 RD3 相比，RSD3 和 RBY 光敏剂的光毒性作用明显较低。
RD3 光敏剂对核梭杆菌和牙龈卟啉单胞菌具有光毒性作用。结果表明，在可见光下应用 RD3 光敏剂可能有助于作为灭活牙周致病菌的辅助治疗方法。
