| Objective: High translucent zirconia has excellent mechanical properties,corrosion resistance and bio-compatibility,and has become the preferred material for the aesthetic implanting abutment material because of its translucency.However,it does not have antibacterial ability,and is easily adhered by bacteria and forms biofilm,causing mucositis around the implant,even leads to implanting failure.Thus,to give the surface antibacterial ability is of great importance.The purpose of this research is to construct a coating with good antibacterial,anti-inflammatory and biocompatible properties by modifing the surface of high translucent zirconia,using the carrying capacity of aluminum silicate porous structure and nano-Ag broad-spectrum antibacterial action and good anti-inflammatory ability,to prevent bacterial infection and inflammation around the implant,to promote the healing at its interface with soft tissue,to increase the success rate of implantation and keep the long-term stability of the implants.First of all,the smooth and porous silver coatings were constructed on the surface of high translucent zirconia,then compared the antibacterial properties of the two materials,studied the biocompatibility and anti-inflammatory ability as well as the mechanism of the silver coating with better antibacterial properties,and explored the influence of zirconia surface change on its translucency and flexural strength,to provid theoretical and data support for the selection of aesthetic abutment material.Methods:(1)Using aluminum silicate vacuum and non-vacuum sintering method,the smooth and porous coatings were constructed on the surface of high translucent zirconia,and then immersed in different concentrations of silver nitrate solution and sintered for the second time,the silver ions in the silver nitrate solution were reduced in place in aluminum silicate coatings.The micromorphological features and structure of the modified coatings of the high translucent zirconia surface were characterized by scanning electron micrograph(SEM),X-ray energy dispersion spectrometer(EDS)and X-ray photoelectron spectroscopy(XPS).(2)Used inductively coupled plasma atomic emission spectrometer(ICP-AES)to compare the silver ion releasement of the smooth and porous silver coatings on high translucent zirconia,and observed different modified coatings to analyze the anti-bacterial capacity to E.coli,S.aureus and L.acidophilus through techniques such as anti-bacterial ring,flat-plate living bacteria count,live/dead fungal fluorescence staining and SEM.(3)Osteoblasts(MC3T3-E1)and fibroblasts(HGFs)were cultured on the silver coated surfaces of the high translucent zirconia,CCK-8,cell adhesion,ALP staining,RT-q PCR,and Western blot technology were used to detect the influence and cytotoxicity of silver coatings on the proliferation,adhesion and bone differentiation of cells.And human monocyte macrophages(TPH-1)was cultured on the silver coated surface of the high translucent zirconia,with and without bacterial lipid polysaccharin(LPS),RT-q PCR experiments were used to detect IL-4,IL-10,TGF-β,IL-1β,IL-6,TNF-α m RNA expression,and Western blot was used to detect the TLR4/NF-κB pathway key protein expression in each group of cells,to analyze the anti-inflammatory effect and mechanism of the silver coating.(4)In the high-translucent,ultra-translucent and traditional zirconia material surface modification experiments,the transmission rate and flexural strength and other major optical and mechanical properties were compared before and after the modification,through FE-SEM,EDS microstructure analysis.Results:(1)It showed from the FE-SEM,EDS,XPS results that the impregnating concentration of silver nitrate solution affected the preparation of aluminum silicate-assisted deposition silver coating,and the high concentration of silver nitrate environment(5mol/l)was more advantageous to the deposition of nano-Ag than the low solution concentration(1mol/l),resulting in more nano-Ag particles,smaller size,but uneven distribution.(2)The ICP-AES results showed that the early silver ion releasing of both smooth silver coating and the porous silver coating were obvious,the silver ion concentration released by the former was higher than that of the latter.But the silver ion concentration released by the porous silver coating was higher than that of the smooth coating when the releasing slowed down.Smooth and porous silver coatings both inhibited E.coli,S.aureus,and L.acidophilus,and porous silver coatings had stronger antibacterial properties.(3)Experiments on biocompatibility showed that the silver coated surface of high translucent zirconia promoted MC3T3-E1 cell proliferation,ALP activity,and the expression of bone differentiation genes Coll A1,BSP,OCN and OPN,and could also promote HGFs proliferation and its adhesion,while had no side effect on the biocompatibility of high translucent zirconia.The silver coating could inhibit and promote the release of inflammatory factors and anti-inflammatory factors respectively,by inhibiting the upward of the TLR4/NF-κB signaling pathway.(4)The comparison before and after the change of the three zirconia materials showed that the translucency and flexural strength of the three materials decreased to varying degrees after the preparation of the silver coating,and there was no difference between the modified high translucent zirconia and modified traditional zirconia concerning the translucency and flexural strength property,which could meet the clinical needs.Conclusion: The silver coating was successfully constructed on the surface of high translucent zirconia,through aluminum silicate sintering and silver nitrate solution impregnation.It was found that the high concentration environment of silver nitrate solution was more advantageous for nano-Ag deposition,and the non-vacuum sintered porous surface was able to obtain a larger number of nano-Ag particles with smaller size.The porous silver coating had better antibacterial properties and good biocompatibility,which was conducive to the formation of the soft tissue closure area around the implant,and could play an anti-inflammatory role by regulating the TLR4/NF-κB pathway,and the translucency and the flexural strength were good.It was suggested that the high translucent zirconia with silver coating had the clinical application potential to improve implanting survival and aesthetic effect. |
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