Abstract: A method for effectively repairing damage to dental enamel. In a repairing process, employed is a repairing agent containing a filling component strong adherable to dental enamel when heated by laser beam irradiation.

Abstract: The present invention is intended to enable the change of the operating mode of an observation apparatus of a video system between a fluorescent observation mode and an ordinary observation mode and to enable the observation apparatus to reproduce a clear image for observation. The observation apparatus in accordance with the present invention uses a principle that an image pickup system provides three color signals, namely, R-, G- and B-signals. The image pickup system of the observation apparatus is provided with an illuminating light selecting means for selectively using light in a specified wavelength region as illuminating light, and a color signal selecting means for selectively providing the color signals. When the specified wavelength region is the visible region, at least the color signals in a wavelength region including the specified wavelength region including the illuminating light are cut off.