The present paper describes a number of laser treatments of hard tissue lesions, including caries diagnosis by Nd:YAG and semiconductor lasers; caries treatment, including caries prevention, by argon, Nd:YAG, CO2, Er:YAG, and Er,Cr:YAGG lasers; removal of dentin caries by ruby, CO2, Nd:YAG, Er:YAG, and Er,Cr:YAGG lasers; and cavity preparation by Er:YAG and Er,Cr:YAGG lasers, including dental pulp response to the cavity preparation, treatment time until the end of cavity preparation, morphology of cavity margin and wall after cavity preparation, and microleakage and surface roughness of cavities. In addition, the morphological characteristics of alveolar bone after ablation by CO2, Er:YAG, Er,Cr:YAGG, and ArF excimer lasers are described.

Keywords: enamel, dentin, dental caries, alveolar bone, semiconductor laser, Nd:YAG laser, CO2 laser, Er:YAG laser, Er,Cr:YAG laser, ArF excimer laser