Abstract: Erbium laser is applied to hard tissues. In erbium laser application, a large amount of energy is absorbed by the irradiated tissue, and incident energy is almost non-residual. This process prevents excessive energy accumulation and thermal damage to the surrounding tissues of the irradiated area. The cleaning and shaping of a root canal are important processes in root canal treatment. After a root canal is prepared by using an erbium laser, a smear layer is not formed on the canal wall, and the dentinal tubule is opened. Erbium laser irradiation combined with ethylene diamine tetraacetic acid or sodium hypochlorite can effectively remove the smear layer, clean the root canal, and open the dentin tubule. Bacterial infection is the main pathogenic factor of periapical diseases. Erbium laser irradiation combined with traditional methods elicits good sterilization effect. When root canal treatment is unsuccessful, apicoectomy is commonly performed to treat periapical diseases. After apicoectomy is conducted using an erbium laser, a smooth, clean, and carbon-free surface is formed in the resection area. This process also results in minimal tissue trauma. Wound healing and apical sealing are also efficient. Erbium laser irradiation requires appropriate energy parameters and thus can avoid damage to periapical tissues. Low energy application via erbium laser irradiation can create good conditions for the adhesion of fiber stem cells.

Key words: erbium laser, periapical disease, root canal therapy, apicectomy