Nd:YAG Laser Effects on Subgingival Microbiota in Stage III-IV Periodontitis

Full-mouth scaling and root planing (SRP) was performed using an ultrasonic scaler (EMS AIR-FLOW MASTER PIEZON®) supplemented by Gracey curettes for subgingival instrumentation. All procedures were conducted under local anesthesia by a calibrated periodontist, with each quadrant treated for a minimum of 30 minutes. Patients received standardized oral hygiene instructions and were scheduled for a 3-month postoperative follow-up.

"In addition to the identical SRP protocol described above, adjunctive Nd:YAG laser therapy (Wiser Waterlase MD, Vista Dental) was applied immediately post-SRP. Laser parameters were set at 150 mJ/pulse, 20 Hz frequency with water (level 1) and air (level 3) coolant. The fiber optic tip (300 μm diameter) was moved in a continuous Zig-zag pattern along the root surface and pocket epithelium, maintaining 2-second irradiation per site at a 30° angle to the tooth axis. Standardized oral hygiene instructions and 3-month follow-up were similarly provided."