Non-surgical periodontal treatment leads to periodontal inflammation resolution and amelioration of the clinical periodontal indices via the microbial load reduction. Additionally, non-surgical periodontal treatment can be performed with different instruments. Ultrasonic scalers with or without hand scalers are more frequently used during Phase I periodontal treatment, however the one who performs the treatment is committed to choose the tools that according to his judgment will lead to the best clinical outcomes following non-surgical periodontal therapy. The aim of this study was to evaluate the effectiveness of non-surgical periodontal treatment with a new oscillating ultrasonic device (Paro) with adjunctive root polishing versus traditional scaling and root planing with ultrasonic device and hand instruments, 3 and 6 months after treatment, at patients diagnosed with chronic periodontitis stage II, III and IV.