A total of 25 patients were treated with a nonsurgical periodontal treatment protocol (NSPTP) consisting of four appointments (three within 1 week and one approximately 30 days later). Nonsurgical periodontal instrumentation was implemented, with the adjunctive use of thermal diode lasers (wavelength of 808 or 980 nm). The patients were scheduled for recall visits every 3 months and reevaluated 1 year post-NSPTP. They were subsequently monitored at 4-month intervals for the remaining 2-year follow-up maintenance period. In total, 698 teeth (210 multirooted and 488 single-rooted) were included in the study. The mean bleeding on probing was 43% at baseline and decreased to 12% at 12 months and to 8% at 3 years. The initial ≥ 6-mm probing pocket depth (PPD) in single-rooted teeth decreased from 6.2 mm at baseline to a mean of 1.8 mm at 12 months and remained at 1.8 mm at 3 years, with a mean clinical attachment level (CAL) gain of 4.4 mm. In multirooted teeth, the PPD decreased from 6.7 mm to a mean of 3.9 mm at 12 months and 3.6 mm at 3 years, with a mean CAL gain of 2.9 mm. The mean overall recession was 0.3 mm at baseline, 0.1 mm at 1 year, and 0.3 mm at the 3-year follow-up. In the short-term followup period, uniform and consistent implementation of the NSPTP used here with adjunctive use of thermal diode lasers seemed to convey therapeutic benefits, stable periodontal soft tissue levels, and satisfactory esthetics in patients with moderate to severe chronic periodontitis. The present protocol is relevant as a treatment option for medically compromised patients, those who refuse or delay surgical treatment, or those who present with other limitations.