Comparison of the effect of wavelength 660 with 808 nm diode as a low level laser on non-surgical periodontal treatment in chronic periodontitis: a double-blind split-mouth randomized controlled clinical trial

Background and purpose Previous studies have shown the effectiveness of low level lasers in non-surgical periodontal treatments as an adjunctive agent. The aim of this study is to evaluate and compare two wavelengths of 660 and 808 nm as low level lasers therapy in non-surgical periodontal treatment on periodontal clinical parameters in patients with chronic periodontitis. Materials and methods This randomized controlled split-mouth clinical trial study was conducted on 71 patients with chronic periodontitis with a periodontal pocket depth ≥ 5 mm or clinical attachment loss ≥ 3 mm in premolar teeth. Clinical periodontal parameters including clinical attachment loss (CAL), gingival index (GI), and pocket probing depth (PPD) were measured in premolar teeth. Scaling and root planning of teeth in the whole mouth were done in one session. Then the laser was irradiated randomly with two wavelengths of 660 nm and 808 nm in two different quadrants. Laser treatment with an energy density of 4 J/cm 2 was repeated at intervals of 1, 3, and 7 days after the initial treatment. Re-evaluation of the clinical parameters was done 1, 3, and 6 months after the treatment of the patients. Data were analyzed with SPSS 26, using the Friedman, Wilcoxon, and Mann–Whitney comparative tests. Results Periodontal clinical parameters improved significantly 1, 3, and 6 months after the intervention in both groups ( P -value < 0.0001), and these changes were greater in the 660 wavelengths. There was a significant difference between the two groups in PPD, GI, and CAL parameters ( P -value < 0.0001). Conclusion The results of this clinical trial study showed that red laser (660 nm wavelengths) significantly improved periodontal clinical parameters compared to infrared laser (808 nm wavelengths).