Effect of butyl toluidine blue-mediated photodynamic therapy on periodontal healing in Type 2 diabetic patients. A randomized clinical trial

Objective: We sought to evaluate the photodynamic effect of butyl toluidine blue (BuTB) as an adjuvant therapy for the treatment of residual periodontal pockets in patients with type 2 diabetes mellitus (DM2). Methods: This randomized clinical study comprised 42 DM2 patients with residual periodontal pockets, defined as probing pocket depth (PPD) ≥ 4 mm and bleeding on probing (BOP). Subjects were assigned to one of the following groups: Subgingival instrumentation (SI): SI performed in a single session; and SI + antimicrobial photodynamic therapy (aPDT): SI in a single session, followed by pocket irrigation with BuTB and irradiation with a 660 nm diode laser at 100 mW for 50 s. Periodontal clinical parameters, glycated hemoglobin levels, and immunological markers in crevicular fluid were assessed at baseline, and after 90 and 180 days. Results: A total of 30 patients completed the study follow-up. Clinically, both groups showed improvements in periodontal parameters over time. The SI + aPDT group exhibited a significantly higher percentage of closed pockets (PPD ≤ 3 mm) and a lower percentage of moderate or deep pockets (PPD ≥ 4 mm) at 90 and 180 days compared to the SI group. BOP was significantly lower in the SI + aPDT group at baseline and 90 days. A reduction in PPD ≥ 4 mm and a gain in clinical attachment level (CAL) were observed at both 90 and 180 days in both groups compared to baseline. In the intergroup analysis, the SI + aPDT group showed a greater reduction in PPD ≥ 4 mm at 90 and 180 days, as well as a significantly improved CAL gain at 90 days compared to the SI group (p < 0.05). No significant differences were observed between groups in immunological biomarkers (90 days period). Conclusion: Both treatment approaches improved periodontal parameters over time. However, the adjunctive use of BuTB-mediated aPDT with SI led to a significantly higher percentage of closed pockets (PPD ≤ 3 mm) and a lower proportion of persistent residual pockets (PPD ≥ 4 mm), indicating a more favorable clinical response in the test group. Clinical significance: Local adjuvant therapy, such as aPDT, in the treatment of residual periodontal pockets may reduce the need for future surgical interventions and retreatment in patients with uncontrolled DM2.