The Efficacy of Laser in Root Canal Disinfection

Inclusion Criteria: * • Patients who are medically free. * Patient's age between 18-35 years. * One single rooted maxillary anterior tooth with necrotic pulp and asymptomatic apical periodontitis requiring root canal treatment. * Patients complaining of no pain and without fistulous tract. * Periapical lesion with a periapical index score of 3 or 4 (Ørstavik, et al. (1986)108 * Closed apex. * Acceptance to participate in the study. Exclusion Criteria: * Patients suffering from any systemic disease. * Patients who had received antibiotics during the last month. * Patients taking analgesics 12 hours before interventions. * Patients with history of tobacco usage * Teeth with vital pulp, calcified canals, and immature or incompletely formed apices. * Teeth with previous endodontic treatment. * Non restorable teeth where rubber dam could not be applied. * Teeth with periodontal pocket more than 3 mm. * Teeth with greater than grade 1 mobility. * Teeth with swelling/sinus tract. * Technical difficulties in the course of root canal treatment for example: * A tooth with curved roots