Effect of 810 nm Diode Laser Irradiation on the Time of Initiation and Depth of Anesthesia for Endodontic Treatment of Mandibular First Molars with Symptomatic Irreversible Pulpitis: A Clinical Trial.

Objective: In endodontic treatments, performing appropriate anesthesia in patients with irreversible pulpitis in mandibular molars may result in pain and severe problems. The irradiation of low-level lasers could be effective in this regard due to its anti-inflammatory and regenerative properties. This study aimed to assess the effect of 810 nm diode laser on the time of initiation and depth of anesthesia for endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis. Materials and methods: This randomized controlled clinical trial evaluated 60 patients requiring endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis and pain score ≥114 according to the Heft-Parker visual analog scale (HP-VAS). The teeth were randomized into two groups of diode laser and control. In the diode laser group, 810 nm diode laser with 300 mW power and 15 J/cm² energy density was irradiated to the buccal surface of tooth crowns for 20 sec at 2 mm distance immediately before anesthesia administration. Laser in off mode was used in the control group. Inferior alveolar nerve block was then performed using 2% lidocaine with 1:80,000 epinephrine. After anesthetic injection, the mandibular first molar and canine teeth (control) were tested by an electric pulp tester every 2 min. Two consecutive negative responses to 80 mA indicated the initiation of anesthesia. HP-VAS forms were filled out by patients to assess their level of pain during the procedure. Data were analyzed by the Student's t and Chi-square tests, and analysis of variance (α = 0.05). Results: No remarkable difference was noted between the laser group and control groups in pain severity or anesthesia onset (p > 0.05). Conclusions: Low-level (810 nm) diode laser did not affect the time of initiation or depth of anesthesia in endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis. Clinical trials registration: Iranian Registry of Clinical Trials (IRCT20181222042076N1).