| Background and ObjectiveThe challenge in the treatment of peri-implantitis lies in the complete removal of bacterial contaminants from the implant surface and the modification of the peri-implant inflammatory state.Macrophage M2 differentiation around the implant is the key to controlling inflammation and promoting bone regeneration.Studies have shown that surface properties such as implant surface morphology and hydrophilicity can influence macrophage polarisation,and that a more hydrophilic,sandblasted,large-grit and acid-etched titanium surface can reduce the secretion of TNF-α,IL-1 and IL-6 to reduce the pro-inflammatory response of macrophages.Studies have shown that neodymium-doped yttrium aluminium garnet(Nd:YAG)lasers can kill periodontopathogenic bacteria,significantly control inflammation and alter the inflammatory state of the peri-implant area.However,the high power Nd:YAG laser can cause thermal damage and damage the surface structure of the implant,and the Nd:YAG laser can change the physicochemical properties of the titanium surface while decontaminating it due to the parameters set,but it is not clear what the differences are between the different energies of the Nd:YAG laser.This project investigates the effect of Nd:YAG laser surface decontamination on the physicochemical properties of the titanium surface by constructing a model of contaminated titanium implants with different energy parameters,and the relationship between macrophage polarisation and inflammatory response.This study is expected to reveal the role of the physicochemical properties of the titanium surface in the regulation of macrophage polarization by Nd:YAG laser decontamination,and more importantly,to provide new ideas for the treatment of peri-implantitis with Nd:YAG laser.Methods1.Contaminated implant models were constructed in vitro and decontaminated using 0.5W and 1.0W Nd:YAG lasers.Scanning electron microscopy,atomic mechanics microscopy and contact angle analysis were used to assess the morphological characteristics of the different titanium surfaces.2.Live/dead cell fluorescence staining and CCK-8(Cell Counting Kit-8,CCK-8)methods were used to examine the effect of contaminated implant surfaces on macrophage growth after Nd:YAG laser treatment at different power levels3.The expression of Ml and M2 surface markers was analysed by flow cytometry,and the activity of M1 and M2 polarisation was measured by quantitative real-time fluorescence polymerase chain reaction(qRT-PCR)and enzyme-linked immunosorbent assay(ELISA),respectively.Results1.After Nd:YAG laser decontamination treatment,no bacterial biofilm remained on the titanium surface,and the original titanium surface morphology was changed,and the hydrophilicity and roughness of the titanium surface were increased(P<0.05).2.Nd:YAG decontamination treatment had no effect on macrophage growth viability and promoted macrophage proliferation(P<0.05).3.Nd:YAG decontamination decreased the detection rate of CCR7 positive cells and increased the detection rate of CD206 positive cells on the titanium surface.Secretion of the inflammatory cytokines IL-1β and TNF-α by macrophages was reduced(P<0.05),while secretion of the anti-inflammatory cytokines IL-4 and IL-10 was increased.Levels of inflammation-related genes IL-1β,TNF-α,IL-6 and iNOS were significantly reduced(P<0.05).The expression of the anti-inflammatory genes IL-4,IL-10 and TGF-β was significantly upregulated(P<0.05).Conclusions1.Nd:YAG laser decontamination treatment changed the surface morphology of titanium,increasing the surface roughness and hydrophilicity2.Nd:YAG laser decontamination treatment altered the surface of titanium and inhibited the polarization of M1-type macrophages and promoted the polarization of M2-type macrophages. |
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