2010 Volume 53 Issue 6 Pages 619-626
Photocatalysis with anatase-type titania is a kind of photochemical reaction that shows catalytic action by irradiating light. A recent study applied photocatalysis of this anatase-type titanium to the bleaching of teeth in dentistry. This study was based on the application in dentistry of ST-01 (average particle size: 7nm) and ST-21 (average particle size: 20nm), which are anatase-type titanium with different particle diameter, and aimed to collect data, such as observation of particles, analysis of the crystal structure, and analysis of photocatalysis based on the data. The crystal structure was analyzed using an X-ray diffraction device (XRD) to observe the titanium particles with a transmission electron microscope (TEM). A mixture of ST-01 or ST-21 and methylene blue solution was irradiated by 365nm light (UV) using a transilluminator or 420-480nm light (LED) using a dental curing unit in order to analyze photocatalysis of ST-01 and ST-21. Photocatalysis was greater in ST-01 (small particle) than ST-21 (large particle), and was developed within 2 minutes after the light irradiation. The more the irradiation time was, the more the photocatalysis occured, which appeared as obvious in ST-01 than ST-21. Photocatalysis was developed by both UV and LED, however, UV showed higher effect than LED.
