Evaluation of two low-level laser techniques as an adjunct to basic periodontal therapy: a randomized clinical trial

To assess and compare two techniques of low-level laser application-transgingival (TLLLT) and intrasulcular (ILLLT)-used in photobiomodulation as an adjunct to basic periodontal therapy (BPT) in patients with periodontitis. A randomized, split-mouth, double-blind clinical trial was conducted, selecting three diseased periodontal sites from different quadrants in each patient. These sites were assigned to one of three treatment groups: SRP (control), SRP + TLLLT (test 1), and SRP + ILLLT (test 2). Low-level laser therapy in the test groups was applied at 48 h, 7 days, and 14 days after full-mouth SRP. Clinical parameters such as probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were assessed at baseline (T0), 3 months (T1), and 6 months (T2). Standardized periapical radiographs were used to assess radiographic bone density (RBD) 6 months post-treatment. Statistical analyses included repeated measures ANOVA for continuous variables and chi-square tests for categorical variables, with significance set at p < 0.05 and a 95% confidence interval. Significant reductions in PD (p < 0.001) and CAL (p < 0.001) were observed across all groups at 3 and 6 months, with no significant differences between groups. There were also no significant changes in BOP and RBD between groups at the follow-up intervals. Adjunctive photobiomodulation did not provide additional clinical or radiographic benefits over SRP alone, regardless of the laser application technique employed.