Oral Titanium Implant Surface Modification And Its Biological Properties

Since Branemark and Schroeder proposed osseointegration of puretitanium implant during the1870s, more and more attentions have beenpaid to oral medical research and applications of titanium implant. Puretitanium used for oral implants has good biocompatibility andanti-corrosive ability, etc. However the osseointegration cycle is too longdue to titanium’s low bioactivity during clinical application, so manyresearchers have been trying to improve the bioactivity through varioussurface modification treatments to reduce the cycle. Currently, themechanism between the modified surface structure and osseointegration isstill not clear which requires further study. We focused on3surfacemodification methods for oral titanium implant and gave the optimizedmodification processing according to the properties of modified surfacestructure and its in vitro osteoblast bioactivity, and discussed osteoblasts’response mechanism on modified surface with different structures.Firstly, we applied3surface modification methods on the polishedtitanium pieces (Pure Ti), which were SLA (sandblasting processingfollowed by acid etching), AO (anodic oxidation processing) as well asSLA+AO (SLA combined with AO) respectively. As a result, we gotthree groups of samples: SLA Ti, AO Ti and SLA+AO Ti. The Pure Ti wasblank control sample. The parameters of SLA processing were asfollowing:150μm glass balls,40s sandblasting time and in10wt%aqueousoxalic acid of90℃for2h. The AO processing was done under the voltageof90V with3mol/L Sulfuric acid solution as the electrolyte.Secondly, we analyzed the surface structure of different samples and their formation mechanisms through morphology, roughness, surfacecomposition, crystalline structure and hydrophilic performance tests. Thesurface morphology of samples after SLA processing was full of2-3umpits and100-400nm holes. The surface of samples after AO processing wasformatted by anatase oxide film with20-400nm holes. While the surface ofsamples after SLA+AO processing was formatted by anatase oxide filmwith micro-nano porous structure.Finally, we studied the in vitro biological behavior of mouse MC3T3-E1osteoblasts on the surface of four groups of samples respectively: Pure Ti;SLA Ti; AO Ti and SLA+AO Ti, including biological toxicity, cellproliferation, cell adhesion and spreading, cell gene expression and celldifferentiation. The test result of biological toxicity showed that the fourgroups of samples were biocompatible. The ALP, OCN and OPN etcexpression results showed that at the second incubation day the metabolicrate of osteoblasts cultured on SLA Ti, AO Ti and SLA+AO Ti wasfaster than on Pure Ti, while the osteoblasts cultured on SLA+AOmetabolized the fastest. After28incubation days, the amount of calciumsalt secreted by osteoblasts cultured on the four groups of samples was asthe following: SLA+AO Ti> AO Ti> SLA Ti> Pure Ti, thus, the surface ofSLA+AO Ti had the best biological activity and could induce boneintegration most.In conclusion, the surface structure with micro-nano porous and anataseoxide film after modified by SLA combined with AO processing couldmaximize the osteoblasts’differentiation ability and had the best biologicalactivity, which was useful for clinical application. We also discussed themechanism between the modified surface structure and its biologicalbehavior.