Unit of Periodontology, University of Parma, Parma, Italy.
J Periodontol. 2011 Aug;82(8):1169-77. doi: 10.1902/jop.2010.100428. Epub 2010 Dec 28.
Laser light has been proposed as a tool to decontaminate the surface of endosseous implants. The effects of this maneuver on the interactions between cells and surface, however, are poorly known. The goal of the present study is to investigate osteoblast growth and differentiation on three commercially available surfaces untreated or after irradiation by erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser at two levels: 150 and 200 mJ/pulse at 10 Hz.
Human osteoblastic Saos-2 cells were plated on machined, sandblasted and acid-etched titanium, or titanium plasma-sprayed disks. The effects of lasing were observed with a scanning electronic microscope, and cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Moreover, we measured the production of the osteoblast-specific protein osteocalcin and of osteoprotegerin in the supernatants by immunoenzymatic assays.
Although no visible changes were observed on machined or titanium plasma-sprayed disk samples at the tested levels, titanium peaks on sandblasted and acid-etched titanium disks appeared fused as a consequence of laser irradiation. Interestingly, cell proliferation was slower on irradiated titanium at both intensities on all the surfaces. Cell differentiation, as assessed by osteocalcin production, was generally unaffected by laser treatment, whereas the production of osteoprotegerin was decreased on all the surfaces irradiated at the intensity of 200 mJ/10Hz.
These results indicate that Er:YAG laser at energy levels used in this study can alter the surface profile of titanium implants and these changes may negatively affect the viability and the activity of osteoblastic cells. Therefore, Er:YAG lasers should be used with caution on titanium surfaces.
激光已被提议用于消毒骨内种植体的表面。然而，这种操作对细胞与表面之间相互作用的影响知之甚少。本研究的目的是研究三种市售表面（未经处理或经铒：钇铝石榴石（Er：YAG）激光照射）在两个水平（150 和 200 mJ/脉冲，10 Hz）对成骨细胞生长和分化的影响。
将人成骨细胞 Saos-2 种植在机械加工、喷砂酸蚀钛或钛等离子喷涂盘上。用扫描电子显微镜观察激光照射的效果，通过 3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴化物测定细胞活力。此外，我们通过免疫酶联测定法测量了上清液中成骨细胞特异性蛋白骨钙素和骨保护素的产生。
尽管在测试水平下，机械加工或钛等离子喷涂盘样品上未观察到可见变化，但喷砂酸蚀钛盘上的钛峰由于激光照射而融合。有趣的是，在所有表面上，两种强度的激光照射都使钛上的细胞增殖更慢。细胞分化，如骨钙素的产生所评估的，通常不受激光处理的影响，而在所有照射强度为 200 mJ/10Hz 的表面上，骨保护素的产生减少。
这些结果表明，在本研究中使用的能量水平的 Er：YAG 激光可以改变钛植入物的表面形貌，这些变化可能会对成骨细胞的活力和活性产生负面影响。因此，应谨慎使用 Er：YAG 激光处理钛表面。
