The Screening Of Micro/Nano Surface Treated By HF Etching And The Effect On Early Biological Activity

With the rapid development of oral implantology,dental implant are more and more popular with doctors and patients.However,there is still some problems,for instance,the long cycle of treatment and low success rate in poor bone quantity patients.Therefore,to promote the integration of bone is a hot issue of clinical implant dentistry.One of the most effective method to promote osseointegration is the implant surface treatment.As one of the most conventional methods,etching has some advantages like simple,clean,cheap and so on.Now the most commonly used acids are HCl,HNO3,etc.Due to fluoride elements can be laoded by HF acid etching process,which have the function of osteogenesis.HF acid etching become a research hotspot.However,Existing research do not have a precise description of HF concentration and etching time,so this study use different concentrations of HF,respectively etching different times,selecting the morphology of different gradient,analysis the material properties and the impact of human BMSCs growth and adhesion.Then observe the early stage osseointegration of implantation through animal experiments.Objective:1 To select the morphology of different gradient treated by hydrofluoric acid etching,analysis the material properties of titanium implant surfaces.2 To analysis the impact of human BMSCs growth and adhesion on gradient titanium implant surfaces.3 To evaluate the influences on the osseointegration in early stage of implantation through animal experiments.Methods:1 Select and analysis the material properties of the morphology of different gradient: titanium plates are treated by 6 different concentrations ofHF,respectively etching 6 different times,according to their surface morphology,3 gradient groups were selected.Smooth group as control.The plates were treated by SEM,AFM,EDS and the surface hydrophilic was analyzed by measuring the contact angle.2 Impact of human BMSCs early growth and adhesion on gradient micro/ nano surface: inoculate the human BMSCs on these treated plates,SEM observation of cell morphology,Fluorescence microscopy observation of the adhesion of cells.3 Animal experiment on osseointegration in early stage of implantation:implants were randomly implanted into the distal femurs of SD rats.3 month later,we use histological examination and biomechanical property to evaluate the influence of the four groups on osseointegration.Results:1 Morphologic observation and selecting: According to the SEM,the polished group as a control group,denoted group A.Three groups has selected from 36 groups,they are 1% 3min,0.5% 12 min and 1.5% 12 min,respectively denoted as group B,C and D.There are some parallelled grooves on group A plates with the same direction of polishing.Groups B,C,D were covered with grooves wide 0.5-1?m,1-1.5?m,1.5-2?m.At high magnification,Group B showed sharp top particles with the diameter of 20-30 nm.Group C is structured by sharp tall columnar approximately 30-50 nm.Group D covered with about 50-100 nm mountain-like characteristics.AFM showed the similar characteristics.2 EDS: the main elements of each group are Ti.Group B,C,D loaded a small amount of F.3 Surface contact angle measurements: the contact angle of the four groups were 45±1.83,16.5±1.18,15±1.07,13.3±1.14,group A was the largest,group D is the smallest.Group B,C,D was significantly lower than group A.4 Primary culture and subculture of BMSCs:After 5 days of culturing human iliac,cells climbed out and 11 th days subcultured.5 SEM observation of cell morphology: More BMSCs on group B,C,D surface,more vigorous growth,and stretched better,showed more filopodia.6 Confocal microscopy observation:Cells on group A surface were Fusiform or triangle.Cells on group B,C,D were polygonal,greater and stretch better,had more lamellipodia and cytoskeletal.Proteins distributed evenly,the boundaries were clear,no fracture or disordered fibrous.7 The cell adhesion: the number of cell adhesion on the surface of group B,C,D was significantly greater than the surface of group A.At 60 min,the number of cell adhesion on surface group D was significantly greater than Group B and C(P<0.05).8 Hard tissue slicing: Implants of group B,C,D had more surrounding mineralized bone matrixes than those of group A.Bone-implant contact(BIC%)of the four groups were 22.46±1.98,33.17±2.2,33.82±3.42and41.04±3.08,respectively,Statistical results showed that group B,C,D had a much higher BIC% than group A,group D was significantly higher than Group B and C(P<0.05).9 Biomechanical test: The maximum pullout force(Fmax)of the four groups were 30.11±3.36,57.92±2.88,57.83±4.09 and 67.44±6.14,respectively.Statistical results showed that group B,C,D had a much higher maximum pullout force than group A,group D was significantly higher than Group B and C(P<0.05).Conclusions:1 We successfully constructed gradient micro/nanorough-surface and laoded F by HF etching.The content of F had no relationship with the concentration of HF or etching time.HF etching groups showed better hydrophilicity.The larger size of micro/nanorough-surface showed better hydrophilicity.2 BMSCs on HF etched surface stretched better and showed more lamellipodia and filopodia.At the same point in time,The number of cell adhesion on HF etched surface is significantly greater than those on the polishing group,The surface covered with 1.5-2?m grooves and 50-100 nm particles were significantly higher than other etching groups.3 HF etched implant surface was significantly better than the polished surface of osseointegration in early stage of implantation.The surface covered with 1.5-2?m grooves and 50-100 nm particles were significantly higher than other etching groups.