Dental Medical Devices, Oral Medicine Devices Phototoxic Effect of Non-Coherent Light on Perio-pathogens Our device for treating microbial diseases in local infections comprises the step of emitting a blue light beam towards the tissue to be treated without warming the tissue so that a selective or non-selective phototoxic effect is exerted inter alia by regulating various levels of parameters selected from blue light. Periodontitis is prevented by inhibiting predetermined bacterial lawn from growing into biofilm. This phenomenon could be enhanced in the presence of chemical cofactors such as oxygen precursors for ROS production. A Method & Device for Teeth Whitening Our invention answers an urgent need for a cost effective bleaching agent containing whitening material which is adapted for homely time-saving use. Moreover, it provides a stable, conveniently applicable product that is adapted to prevent chemical swallowing effects as well as contact with soft body tissues and teeth erosion while possessing hardening abilities during the treatment process. A Method & Device for Teeth Whitening Our invention answers an urgent need for a cost effective bleaching agent containing whitening material which is adapted for homely time-saving use. Moreover, it provides a stable, conveniently applicable product that is adapted to prevent chemical swallowing effects as well as contact with soft body tissues and teeth erosion while possessing hardening abilities during the treatment process.