Application of Sintered Titanium Dioxide to Biomaterials：Sintering Temperature of Anatase-Type TiO₂ and Cell Proliferation of L929 Cells

Abstract

The purpose of this study was to create biomaterials from anatase-type titanium dioxide (TiO₂). TiO₂ is known for photocatalysis and osteogenesis. In order to apply this function to orthodontic brackets and coating materials for implants, the relationship between sintered temperature and cell proliferation was examined.
In addition, sintered temperature, crystal structure and the surface properties of sintering bodies were investigated.
Experimental Method: We began by pressure-molding anatase-type TiO₂ powder and sintering it at temperatures of 700, 800, 900, 1,000, 1,100, 1,200 and 1,300℃ to produce sintered bodies for use as samples. We then used surface roughness, x-ray diffraction and scanning electron microscopy to observe the surface properties and texture. Moreover, we seeded the samples produced at each of the sintering temperatures with L929 mouse fibroblast cells in order to evaluate the cytocompatibility in terms of cell proliferation.
Results: For the samples sintered at 700℃, only the crystalline phase of anatase-type TiO₂ was confirmed, but for the samples sintered at 800℃ or 900℃ the crystalline phase of anatase-type TiO₂ and in some cases rutile-type TiO₂ crystalline phases were confirmed. At sintering temperatures of 1,000℃ or higher, all samples were transformed into rutile-type TiO₂.
In the test of cytocompatibility, the samples of anatase-type TiO₂ sintered at 700℃ were found to have reduced cell counts after 24 to 96 hours of incubation compared to those immediately after being placed in the incubator (0 hour). However, the samples sintered at 800℃ or higher than 900℃ whereby the samples were transformed to rutile-type TiO₂ showed remarkable cell proliferation even after time had passed.