Study On Preparation And Propetries Of Nano Silver Coating Modification Of Denture Base

Base resin is commonly used in prosthodontics denture base materials with a high degreeof smoothness, good chemical stability, resistance to aging. However, due to the complexityof the microorganisms in the oral environment, vulnerable plaque attached to the surface ofthe denture base and lead to denture stomatitis and other oral mucosal lesions. It is a seriousproblem to give the denture base antibacterial properties for reducing microorganisms sojourn.Nano silver antimicrobial agent is commonly used as inorganic antibacterial agent which havestable antibacterial effect no bacterial resistance. The present study intends to use ionsputtering technique in the preparation of nano-silver coating on the surface of the denturebase for surface modification and cytotoxic and anti-bacterial properties of the modifieddenture base materials were tested in order to provide the basis for clinical application.Based on whether disposed by silver ion sputtering, the experiments were divided intocoating groups (coating groups were further divided into the10s,20s,40s,60s,80s,100s groupsaccording to the sputtering time) and denture base group.Surface microstructure of coatinggroups and denture base group material were observed by scanning electron microscopy(SEM), and ingredients of material surface were determined with energy dispersivespectrum(EDS) analysis; methyl thiazolyl terazolium(MTT) method was used to analysisL-929cells proliferation rate and cell toxicity grade while the coating groups and denture basegroup test specimens,negative control(polyethylene, PE) and positive control group(PVC-org.Sn) were co-cultured with L-929cells,the blank control group was the purecell;Acridine Orange(AO) Staining was used to detected for the changes of cellar morphologyand cell adhesion state on the surface of coating groups and denture base resin group.Theantibacterial properties of coating groups were determined by the bacterial membraneadhering method and the bacterial inhibition ring method with the Porphyromonasgingivalis;Streptococcus mutans and Candida albicans.SEM observation found that the surface of control group specimens were smooth,whereas dense and uniform distributed nano silver particles were visible on the surface ofcoating groups specimens. The silver particles were round, and the diameter size was10nm.MTT assay showed that after co-cultured with control group specimens, L-929cell had higher proliferation rate than100%at24h,48h,72h, and cytotoxicity were graded0. AcridineOrange (AO) Staining results showed that L-929cells are rendering the fluorescent green anduniform distribution on the surface of base resins group and silver coating all groups after24hours co-culture. The Candida albicans; Streptococcus mautans; Porphyromonas gingivaliswere tested by the bacterial inhibition ring method,and the results of coating groups showedthat no formed bacterial inhibition ring with the surface of coating groups and denture baseresin group. The membrane adhering method results showed that all of bacterial coloniesappeared at control group, but without anything at the coating groups.Ion sputtering method success in the preparation of the nano-silver coating modifieddenture base materials. The coating material in each group had no cytotoxicity, andnano-silver modified denture base material has good antibacterial properties.