| Background and Objective:Since the middle of last century, dental implant has been accepted by more and more patients. Dental implant has the advantages of no damage to adjacent teeth, chewing function recovered well, comfortable and beautiful. Dental implant has become one of the most ideal method for restoration of dental system function.Osseointegration between dental implant and bone is the basis for successful repair, and surface treatment is one of the important factors influencing osseointegration. Now, titanium is the most widely used implant materials for excellent mechanical properties and biocompatibility. But the titanium is bio inert metal, functional reconstruction needs long time to heal after implantation. The tissue around the implant reaction is non-specific and randomness, interface with the bone tissue is mainly physical integration of mechanical locking mode, lack of effective chemical combination. In order to improve titanium implant compatibility and ossointegration, the surface treatment has been a hotspot of research in implant.The implant surface treatment is to make the surface roughness with physical and chemical methods. Implant with rough surface has the biological adhesion, surface hydrophilicity, bone affinity and potential suitable property. The implant surface treatment includes surface additive, subtractive method and other methods. Surface additive including the:anodic oxidation method, titanium plasma sprayed hydroxyapatite coating method. Subtractive surface including the:sand blasting, acid etching, sandblasting and etching.Rough implant surface can significantly change the surface properties, so as to promote the formation of osseointegration, improve the success rate of planting. The implant surface roughening treatment has a positive effect to the surface tension increases, osteoblast differentiation, amplification and early bone interface, chondrocyte differentiation and expansion. Studies show that micron surface can increase the bone bonding area, stable extracellular matrix protein scaffolds and blood clot, provide stable micro environment for the proliferation and differentiation of osteoblasts; Nano surface structures, which mimic the natural cell growth environment, can promote the protein adsorption, bone cell attachment and proliferation and differentiation. The surface including micro and nano structure has become the future development trend of implant.A large number of studies show that non coating surface treatment compared with the method of implant surface treatment coating has more advantages, is currently the mainstream of body surface treatment plant.the Sandblasted and Acid-etched (SLA) surface has been widely used in implant surface treatment, and its mechanical biocompatibility has been recognized. The holes with diameter10μm-30μm in the implant surface can be obtained by the large particles blasting, these holes were good for the bone formation. Meanwhile, a large number of pores were formed by the acid-etched method. To some extent, titanium implant surface was also cleaned, that would increase their surface hydrophilicity. Surface treatment method of sand blasting and acid etching also has some disadvantages:such as not controlled blasting operations, the formation of the pit size uncertainty can directly affect the implant surface osteogenic efficiency; In addition, SLA surface treatment of implant surface technology can be embedded to some particles such as Al2O3which has unfavorable on osseointegration.Laser is widely used in metal surface treatment for its processing accuracy, high efficiency and strong controllability. With the development of laser technology and oral implantology, laser technology are introduced into the implant surface treatment field. Laser surface treatment technology is different sandblasting and etching. Laser surface treatment is a non-contact cleaning technology. Research shows that the laser combined etching increases the absorption of bone cells, improve the bone bonding effect. Cho planted implant treated with laser, increased the bone contact area, more conducive to the growth of bone cells.With the development of nanotechnology, study on the surface structure of metal materials into the nanometer era. Titanium dioxide (TiO2) nanotubes is a nanometer titanium metal surface processing of porous structure, is composed of nanoscale tubular structures by surface and perpendicular to the material, can effectively increase the planting area of body surface, enhanced surface energy. In2001, Gong first reported the titanium substrate using anodic oxidation, electrochemical method in hydrofluoric acid electrolyte prepared uniformly ordered TiO2nanotube, so preparation of TiO2nanotube array arranged in neat uniform, and the Schottky barrier and titanium metal conductive substrate directly connected, with very strong, showing a highly ordered and the low aggregation, quantum effect has large surface area, strong adsorption capacity and higher, nano effect can produce a specific. Recent studies found that TiO2nanotubes have potential applications in biomedical field. KarlaS in vitro experiment observed nanotube can promote the migration of stretch, bovine vascular epithelial cells. The study of Seimghan found in the surface material has the nanotube morphology, osteoblast cell process can be extended to the nanotubes, increase osteoblast proliferation up to300%-400%.Nano structure can promote the growth of osteoblasts better than Micron structure, the reason is that the nano structure bionic function, bone mineral diameter of nanometer level; The nano structure increase the planting area, can provide more sites for the bone cell adhesion; Cell synapse can extend into the nanotube structure, become the anchor point, thus promote cell adhesion, adhesion and growth; The nano structure can absorb the extracellular matrix protein, the conformational change of protein, promote cell attachment and growth of receptor recognition. Research confirmed that the nano structure can induce the formation of bone like apatite in materials and tissue interface, and the surface nanostructure materials has stronger adsorption to the protein molecule, nanoscale protein to specific "recognition" nano surface structure, protein molecular conformation and activity of adhesion process of change than before. The bone like apatite deposited on the surface and the protein, polypeptide, cytokines,adhesion on the surface could start the second signal pathways s through cell surface ligand sites, ion channels, thereby promoting the bone marrow stromal cells and osteoblasts aggregation, adhesion, proliferation, differentiation, cytoskeletal spreading and secretion of matrix and mineralization series of reactions.The Kubota study showed that the TiO2nanotubes promoting effect is better than that of hydroxyapatite bone tissue growth. Hydroxyapatite has osteoinductive, suggesting that the TiO2nanotubes have a similar effect.The clinical application of TiO2nanotube implants in the teeth has the great application potential.Combined with a variety of processing methods on the implant surface is the growing trend of surface treatment, such as the recent reported in sandblasting etching and micro-arc oxidation, micro-arc containing silver and non containing silver and other integrated approach between the surfactant and bone effects.Prodanov’s study was the latest research in laser implant surface treatment reports, there was the comparative study of laser-treated with the Sandblasted/acid-etched, both of them obtained good osseointegration. It provided timely experimental basis and theoretical basis for further study in laser surface treatment.Although there has been research on sandblast and acid etching and laser many, but still no comparative study of laser etching and sandblasting etching of the nanotubes and reports. Whether the osseointegration of laser/acid/nanotubes modifying(LAN) surface had the some effect as or better than the Sandblasted/acid-etched surface was to be determined yet.In addition, our research group had been done comparative study about Laser-treated/acid-etched surface and the acid-etched surface, we found that two surface had the same biocompatibility and osteoconduction. The study was intended to changed some conditions of combinating with nanotubes,and then made a comparative study with the sandblasted/acid-etched surface by animal experiments, so as to provid experimental basis and theoretical basis for in-depth study of the laser/acid/nanotubes modifying, to seek a better implant surface treatment technology eventually was also the experimental target.Methods and materials1. Preparation of laboratory samples:based on foreign literature and research purposes, using precision CNC machine tools to produce experiment implant; By surface treatment method, according to pre-determined and related experimental parameters, prepared two good implant surfaces:the laser/acid/nanotubes modifying surface and the sandblasted/acid-etched surface.2. The test of physical and chemical properties:measure the morphology, roughness, elemental composition with scanning electron microscopy, BMT Experi3D surface topography instrument, respectively, to assess the physical and chemical properties of SLA and LAN surfaces.3. Making implant bone tissue sections and measurement of experimental: After decalcification, the anatomy of the rabbit tibia were made into paraffin section for HE staining observing; The bone tissues with implant were used to made sections of undecalcified, osseointegration growth rate,theBA%and the BIC%was assessment and calculated by the fluorescence labeling and staining.4. The BA%and BIC%data, statistical analysis obtained experimental results.Statistical analyses:The experimental data are expressed as mean±standard deviation (SD). Statistical analysis was carried out by SPSS(?) vl6.0software (SPSS Inc., Chicago, USA). For the single factor data, when meet the normal distribution and homogeneity of variance, using two independent sample t test and single factor variance to the overall mean comparison; When the data not meet the normal distribution or variance not neat homogeneous, using two independent sample t’test or rank sum test; For two factors of single variable data with normal distribution and homogeneity of variance, to analyse the main effect and interaction by analysis of variance of factorial design. Hypothesis test for two-sided test, the test level was0.05, probabilities (P)>0.05was considered to be no statistically significant; Probabilities (P)<0.05was considered to be statistically significant.Results: 1. Through access to a large number of domestic and foreign literatures and combined the purpose of the present study, using precision CNC machine tools produced some experimental implant. According to pre-set surface treatment methods and experimental parameters, two different implant surfaces were made: Laser/acid/nanotubes modifying surface and Sandblasted/acid-etched surface.2. Results of the physical and chemical nature detecting:both of SLA and LAN obtainted two rough structure, the surface roughnesses of LAN was bigger than the SLA (LAN:Ra=8.09±0.09μm; SLA:Ra=2.09±0.13μm)(P<0.05). A few oxide aluminum particles was still existed.3. Both groups obtained good osseointegration. tThe BA%and BIC%of LAN was better than the SLA (P<0.05).Conclusion:The surface treatment methods of the laser/acid/nanotubes modifying and the sandblasted/acid-etched could produce the rough surface, the former was more cleaner and more uniform than the latter, but both of them had good biocompatibility and promoted a good implant osseointegration, the LAN was better than SLA. |
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