The general principles behind laser photodynamic therapy are briefly considered with special emphasis on their application in dentistry at the present stage of the development of medical science. It is thought that the initial stage of the process underlying the photodynamic treatment is the energy transfer onto oxygen from the excited (triplet) states of the photosensitizing dye molecules accompanied by the formation of reactive singlet oxygen. The therapeutic action of such treatment is based on the oxidative potential of singlet oxygen which initiates the destructive processes leading to the death of viruses, cells, and tissues that need to be eliminated. It has been demonstrated that singlet oxygen can also be generated in the absence of the photosensitizers by the direct excitation of the oxygen molecules with infrared laser radiation corresponding to the maxima of the absorption bands of the molecular oxygen dissolved in the tissues. It is speculated that the pigment-free laser generation of singlet oxygen with the use of the stationary and pulsed beam laser sources may provide a promising tool to be applied for phototherapy in practical medicine and dentistry.