Study On The Effects Of Implant Surface Modification On Different Bacterial Biofilms

Objective:It has always been the focus of scholars to improve the antibacterial efficacy by surface modification of implants.The purpose of this study is to investigate the adhesion effect of three different implant surface treatments on the biofilm of Streptococcus sanguinis,Fusobacterium nucleatum and Porphyromonas gingivalis related to the peri-implantitis.In this study,three surface treatment methods commonly used in clinic,namely,large-particle sand blasting and acid etching(SLA),electrodeposition of hydroxyapatite coating(HA)and micro-arc oxidation(MAO),were used to observe the adhesion of pure titanium surface after different treatments,so as to explore the surface morphology more conducive to the long-term survival rate of implants.Method:1.The titanium discs were divided into three groups,and the surface was modified,which were sandblasted,large-grit and acid-etched(SLA),micro-arc oxidation(MAO)and electrodeposited hydroxyapatite(HA).2.The surface morphology was observed by scanning electron microscope after gold spraying.The profilometer is used to measure and calculate the surface roughness(Ra).3.P.gingivalis,F.nucleatum and S.sanguinis were cultured on the surface of three titanium discs for 4 days to prepare bacterial biofilm.4.MTT and CFU methods were used to investigate the adhesion of three bacteria.5.Scanning electron microscopy(SEM)was used to observe the bacterial biofilm and to explore the adhesion of different bacteria on different physical structure surfaces.Results:1.Through SEM observation,the surface of HA group is a large number of "rod" structures with irregular morphology;the surface of Mao Group is a "crater" like structure with an aperture of 0.1-1?m;the surface of SLA group is irregular concave structure with different sizes and sharp edges.The surface roughness(Ra)of the three groups was SLA < HA < MAO,and there was significant difference between Mao Group and the other two groups(P < 0.05).2.The number of F.nucleatum biofilm in SLA group was the lowest,and there was significant statistical difference compared with the other two groups(P < 0.05);the bacterial activity of S.sanguinis biofilm was the lowest in SLA group and the highest in HA group,but there was no statistical difference between the three groups(P > 0.05);the bacterial activity of P.gingivalis biofilm was the highest in MAO Group,and there was significant statistical difference compared with the other two groups(P < 0.01)3.SEM observation shows that the activity of bacterial biofilm is related to the morphology and structure of implant surface.Conclusion:(1)The quality of bacterial biofilm formation does not depend entirely on the surface roughness of the implant.Different kinds of bacteria will choose more suitable surface structure for survival according to their morphology.(2)Compared with Microarc oxidation(MAO)and electrodeposition of hydroxyapatite(HA),the surface morphology of the implant treated by SLA is not conducive to the adhesion and survival of bacteria.