Periodontitis is a chronic inflammatory disease associated with biofilm characterized by progressive destruction of the supporting apparatus of the tooth. Gradually, it results in a loss of teeth and impaired masticatory and aesthetic function, which negatively affects the quality of life of an individual and their general health. Due to its high prevalence, it is a serious public health issue. The main goal of periodontal therapy is to eliminate the etiological causative factors of periodontal disease from the root surface in order to re-establish periodontal health. Nonsurgical periodontal therapy involves a mechanical instrumentation of the contaminated root surface and the application of chemical antimicrobial and anti-infective agents. Dental lasers are used as an adjunct to non-surgical periodontal therapy or as an alternative to the classical mechanical instrumentation of a contaminated root surface. Compared with mechanical instrumentation alone, the additional use of lasers after the initial periodontal therapy contributes to the improvement of clinical parameters, especially in the case of moderate and severe periodontitis. Dental lasers can also be used as a light source in antimicrobial photodynamic therapy. The therapeutic effect is the elimination of pathogenic microorganisms without adverse effects on the organism and the development of bacterial resistance. It is based on a photochemical reaction involving a light source, photoactivator and molecular oxygen.