Laser photobiomodulation and photodynamic therapy are new methods for bacteria elimination and can be successfully used as means for preprosthetic periodontal non-surgical preparation. The use of low-level laser therapy, especially in a combination with a photosensitizer, leads to increase of the ATP production, improvement of the oxidation-reduction potential of the cells, as well as bacteriolysis. Neither the dye itself nor the laser is capable of reducing the number of bacteria as much as their combination. The advantages of these methods, compared to the use of antiseptics or antibiotics, are their local action, absence of systemic side effects, lack of need for maintaining high concentration of the dye and advanced healing.