Dervisbegovic, SelmaSelmaDervisbegovicLettner, StefanStefanLettnerTur, DinoDinoTurLaky, MarkusMarkusLakyGeorgopoulos, ApostolosApostolosGeorgopoulosMoritz, AndreasAndreasMoritzSculean, AntonAntonSculeanRausch-Fan, XiaohuiXiaohuiRausch-Fan2025-05-202025-05-202025-04-25https://boris-portal.unibe.ch/handle/20.500.12422/210206Background Low-level laser therapy (LLLT) has been shown to exert biostimulatory effects, including increased cell proliferation and accelerated wound healing. Hence, the use of LLLT as an adjunct to scaling and root planing (SRP) for improved periodontal treatment outcomes has been examined. The aim of this study was to evaluate the clinical effect of adjunctive LLLT in the treatment of periodontitis with a 980-nm diode laser.Materials And Methods Patients with a periodontal screening index of 3 or 4 who met the inclusion criteria were recruited and randomized into two groups for treatment allocation in a split-mouth design. The maxillary and mandibular left or right quadrants of the patients were assigned to either the test (SRP + LLLT) or the control (SRP) group. During the two final debridement sessions, LLLT was applied on one side of each study participant´s upper and lower jaws. The reevaluation of the clinical parameters and microbiological assays was performed 12 weeks after the initial therapy.Results Both groups presented significant reductions in clinical parameters (p < 0.001). However, no statistically significant differences between the test and control groups were found for any of the parameters (all p values were greater than 0.05). The recolonization of P. gingivalis and T. denticola was not significantly reduced in the laser group.Conclusion The clinical parameters in both groups improved similarly after initial periodontal treatment. LLLT with the chosen settings did not show a beneficial effect during the initial nonsurgical treatment of periodontitis.Clinical Relevance LLLT is under discussion for periodontal therapy as a promising treatment modality. Compared with nonsurgical therapy alone, adjunctive periodontal treatment with a diode laser did not improve the clinical parameters of periodontitis patients in this study. Currently, there is no recommended treatment protocol for adjunctive LLLT in periodontitis, which needs to be further investigated with other laser settings.Clinical Trial Registration ISRCTN registry (#ISRCTN11275257), retrospectively registered, 16.10.2023.enLow-level laserPeriodontal diseasePeriodontitisPhototherapyRandomized controlled trial600 - Technology::610 - Medicine & healtharticle10.48620/881304028133910.1007/s00784-025-06289-2