Minimally invasive periodontal surgery with antimicrobial photodynamic therapy versus regenerative surgery for intrabony defects: a split-mouth randomized controlled trial.

BACKGROUND: Residual intrabony periodontal defects often require surgical intervention. Minimally invasive periodontal surgery with adjunctive antimicrobial photodynamic therapy (MIPS+aPDT) may improve microbial control and healing while reducing treatment-related morbidity. OBJECTIVES: To compare the effects of non-surgical periodontal therapy (NSPT), open flap debridement with demineralised freeze-dried bone allograft (OFD+DFDBA), and MIPS+aPDT on red-complex bacterial activity (primary outcome) and on clinical, radiographic, biochemical, wound-healing, and patient-reported outcomes in intrabony periodontal defects. MATERIALS AND METHODS: In this split-mouth randomised controlled clinical trial, 20 patients with Stage III/IV periodontitis contributed three comparable intrabony defects (60 sites), allocated to NSPT (control, Group1), OFD+DFDBA (test, Group2), or MIPS+aPDT (test, Group3). Dysbiosis was assessed using BANA enzymatic activity at baseline, 1 and 6 months (primary outcome). Secondary outcomes included probing pocket depth (PPD), clinical attachment level (CAL), gingival recession (GR), early wound healing score (EHS-24), radiographic bone fill, gingival crevicular fluid MMP-1 levels (baseline, 24 h, 48 h), and patient-reported outcomes (VAS). Data were analysed using mixed-effects models and multilevel ordinal regression (α=0.05). RESULTS: All groups demonstrated a significant reduction in BANA positivity over 6 months (p<0.01). Compared with NSPT, OFD+DFDBA reduced the odds of higher BANA scores by 83.8% (OR=0.162; 95% CI: 0.039-0.680; p=0.013), while MIPS+aPDT reduced the odds by 93.5% (OR=0.065; 95% CI: 0.016-0.265; p<0.001). Both surgical groups showed significantly greater PPD reduction and CAL gain compared with NSPT (p<0.001). OFD+DFDBA demonstrated the highest radiographic bone fill, whereas MIPS+aPDT achieved significantly less GR, superior early wound healing, and better patient-reported outcomes (p<0.01). MMP-1 increased significantly at 24 h across groups without differences between treatments, indicating a common acute inflammatory response. CONCLUSION: MIPS+aPDT provided the most favorable reduction in dysbiosis, alongside comparable clinical and radiographic improvements, and reduced postoperative morbidity, suggesting it as a clinically advantageous approach for intrabony defect management.