플라즈마 전해 산화법으로 Ca, P, Si 및 Mn 도핑된 치과 임플란트 합금의 생체적합성과 표면특성

Abstract

Studies on methods for improving surface characteristics to increase the binding between the bone and the implant surface are being actively conducted nowadays. Among the various methods, plasma electrolytic oxidation (PEO) is a method for surface processing in which a biocompatible oxide film is formed using a number of ions. Although studies using the inorganic compounds of bones, calcium and phosphorous, which are the main components of teeth, and magnesium are being actively conducted, there is a lack of studies using other elements. Therefore, in this study, films were formed by PEO treatments in electrolyte solutions containing of calcium, phosphorous, silicon, and manganese, which were constituent elements of natural bone, on a Ti-6Al-4V ELI disk and observations were made. PEO was conducted for 3 minutes at 280V in the electrolyte solutions created by using calcium acetate monohydrate, calcium glycerophosphate, manganese(II) acetate tetrahydrate and sodium metasilicate nonahydrate. The PEO-processed surface image and the crystal phase of the specimen were analyzed using FE-SEM, EDS, XRD, and FT-IR. In addition, for analyzing the biocompatibility, potentiodynamic test and AC impedance test were conducted in 0.9% NaCl solution, and then, cell proliferation and cell adhesion tests were conducted using MC3T3-E1 cells. From these experiments, the following conclusions were drawn:

1. The surface images of the specimen processed by PEO commonly showed porous structures. As the content of Mn increased, oval and irregular pore structures were identified. As the content of Si increased, the areas occupied by pores were increased.

2. On the evaluation of corrosion, as the content of Mn increased, the corrosion resistance was decreased due to the influence of pores. However, the corrosion resistance of Si surface increased due to a stable SiO2 oxide film. In cases where the surfaces of Mn and Si were processed complexly, outstanding corrosion resistance was observed compared to that in cases where the surface was processed separately due to a variety of oxide films.

3. From the result of cell growth using MC3T3-E1 cells, it was observed that cell adhesion to the surface processed by using a complex of Mn and Si was better than that to the surface processed by PEO with a single element.

Based on these findings, it is suggested that if Mn and Si are used in the surface process in a complex way, they will form a film with a porous structure which is advantageous for achieving osseointegration, which makes it possible to shorten the recovery period after clinical implantation of dental implant.