Influence of antibacterial effects of tetracycline, laser, and photodynamic therapy on cell viability, cell damage, and virulence of Porphyromonas gingivalis

•Photodynamic therapy is more effective than laser and tetracycline on P.gingivalis.•Tetracycline causes equal cell damage as tetracycline.•Photodynamic therapy is able to neutralize gingipains.•Photodynamic therapy using toluidine may be the future for rendering personalized care. This study compares and evaluates the efficacy of tetracycline, laser and photodynamic therapy on bacterial counts, cell damage, cell viability and neutralization of gingipains. P.gingivalis (ATCC 33,277) was cultured anaerobically. The minimal inhibitory concentration (MIC) for 50% inhibition of P.gingivalis by tetracycline, laser, and toluidine blue (TB) was determined using spectrophotometry. The antibacterial effects, cell viability, cell damage and neutralization of gingipains of the treated groups was evaluated by microbial culture and counting, 2,3 Bis 2 Methyloxy-4 Nitro-5 Sulphophenyl 2 H tetrazolium-5-Carboxaanilide (MTT) assay, lactate dehydrogenase (LDH) assay, and gingipain assay (BAPNA). The MIC of tetracycline, toulidine, diode laser (810nmm; 0.5 Watts) is 1 µg/mL, 50 µg/mL and 15 s respectively. Comparative analysis for bacterial colony reduction was highest in tetracycline followed by PDT and then laser group at p