A dental treatment system has a light irradiation device (2) and an image display (3). The light irradiation device has a polymerization light source (5a) for emitting blue light and a camera (6) for capturing a series of images. The system is set up for generating a first marker (11) and a second marker (20) superimposed with the images and to display the first marker (11) in a fixed positional relationship to an image pattern recognized in a first and in a second image of the series of images and to display the second marker (20) in a fixed positional relationship to an image area underlying the images.
