The invention relates to a light curing device comprising a light source that is arranged in the hand-held light curing device and has in particular a plurality of mutually adjacent chips which are arranged next to one another and form a light source and in front of which a light guiding element extends. The light curing device also comprises at least one sensor, which is sensitive to light in the emission wavelength range of the light source, and a control device for controlling the light source during the polymerization process, the sensor being connected to the control device. The control device continuously or at least periodically monitors the output signal of the sensor during the polymerization process and adapts the light output and/or the polymerization time in the event of a reduction of the output signal. The control device adds up the reflected radiation detected via the light exit surface (10) in order to calculate a possible location deviation, and the light exit surface (10) of the light guide is larger than or equal in size to the largest dental restoration (12) to be cured, the light exit surface having a cross-sectional area of more than 1 cm2 in particular.