Low-Level Laser and Antimicrobial Photodynamic Therapy Reduce Peri-implantitis–related Microorganisms Grown In Vitro

Abstract Objective Currently, dental implants are a predictable treatment option for oral rehabilitation; however, complications such as peri-implant diseases are increasing every day. Thus, the aim of this study was to verify the efficacy, in vitro , of two protocols against cultures of periodontal biofilm and Staphylococcus aureus . Material and Methods Petri dishes for each of the following groups were used: control groups (C)—plates inoculated with periodontal biofilm (C.B; n = 4) or S. aureus (C.SA; n = 4) without any treatment; laser groups—plates inoculated with periodontal biofilm (low-level laser therapy [LLLT].B; n = 4) or S. aureus (LLLT.SA; n = 4) and treated with LLLT (660 nm, 30 mW, 50 J/cm 2 , and 47 seconds); antimicrobial photodynamic therapy groups (aPDT)—plates inoculated with periodontal biofilm (aPDT.B; n = 4) or S. aureus (aPDT.SA; n = 4) and treated with aPDT (red laser 660 nm, 30 mW, 50 J/cm 2 , 47 seconds + toluidine blue O (TBO) 100 µg/mL, and 1 minute). After treatments were performed, the contents of all plates were diluted and seeded for counting colony-forming units (CFUs). Statistical Analysis Results were analyzed with one-way analysis of variance (ANOVA), Tukey’s test, comparison of percentages, and independent t -tests with a 5% significance level. Results Both treatments, LLLT and aPDT, significantly reduced the number of CFUs for the two types of culture, LLLT.B (3.69 × 10 6 ± 0.20), aPDT.B (2.79 × 10 6 ± 0.13), LLLT.SA (4.10 × 10 6 ± 0.12), and aPDT.SA (3.23 × 10 6 ± 0.10) when compared with control groups C.B (5.18 × 10 6 ± 0.43) and C.SA (5.81 × 10 6 ± 0.16; p = 0.000). When treatment groups were compared separately, there was also a statistically significant difference ( p = 0.000). None of the protocols were able to eliminate cultured microorganisms. Conclusion The LLLT and aPDT protocols effectively reduced cultures of periodontal biofilm and S. aureus in vitro , with the superiority of aPDT.