Hideyuki Negishi

Response of human fibroblasts to implant surface coated with titanium dioxide photocatalytic films

PURPOSE This study was to develop a titanium dioxide (TiO(2))-coated implant abutment, surface with ultraviolet (UV) light-induced hydrophilicity and investigate the initial response of human, fibroblasts to the surface modification. MATERIALS AND METHODS Commercially pure titanium (JIS 2 grade) disks were coated with TiO(2) to various, thicknesses (1, 2 or 3 μm) using peroxotitanium acid solution. The surface characteristics of each disk, were examined with X-ray diffraction (XRD), surface roughness equipment and scanning electron, microscopy (SEM). The hydrophilic change of each disk was determined by the contact angles at 0-24h, after 24-h UV irradiation. The biological response at the surface of each disk was examined by using, human periodontal ligament fibroblasts (HPLFs). The data were statistically analyzed with analysis of variance (ANOVA) and multiple-comparison tests. RESULTS The TiO(2)-coated disk surface had an anatase structure. Surface roughness did not differ, significantly among the disks; the surface morphology was smooth and had a hydrophilic or superhydrophilic, status. HPLF proliferation significantly increased on the TiO(2)-coated disks compared with the uncoated disks and depended upon the coated film thickness. CONCLUSION An anatase TiO(2)-coated surface under UV irradiation markedly improves the initial response of human fibroblasts.

Scanning tunneling microscopic observation of dental structures of a permanent tooth

Abstract An application of scanning tunneling microscopy to biological research is presented on observation of micro-structures of a permanent tooth. This observation provides micro-structural images of cross-sectional surface of thin-sliced samples of dentin and enamel of a human permanent tooth within a nanometer region under atmospheric conditions at room temperatures. The scanning scale used in this study is in 313–10,000 nm for measurements of dental specimens. Several tunneling microscopic images of the dental