The in vitro antibacterial efficacy of advanced platelet-rich fibrin plus supplemented with metronidazole against Fusobacterium nucleatum.

Purpose: Owing to its high antibacterial efficacy and low adverse effects, local antibiotic administration has attracted attention. This in vitro study compares the antibacterial effectiveness of advanced platelet-rich fibrin plus (A-PRF+) combined with metronidazole produced under different protocols.

Materials and methods: Eight volunteers participated in this study. A 0.02% metronidazole was supplemented into A-PRF + based on four protocols concerning time (before vs. after centrifugation) and dosages (0.25 vs. 0.50 mL), yielding four groups: B25 (before centrifugation, 0.25 mL), B50 (before centrifugation, 0.50 mL), A25 (after centrifugation, 0.25 mL), and A50 (after centrifugation, 0.50 mL). Agar diffusion experiments on Fusobacterium nucleatum strain ATCC 25,586 were conducted to determine the bacterial efficacy of the four groups on three time points: day 2 (D2), D3 and D4. Images of the bacterial inhibition zone (BIZ) at assessment times were captured to measure BIZ dimensions using ImageJ software.

Results: No significant difference was found between the BIZs of B25 and B50; however, the BIZs of A50 were significantly higher than those of A25. BIZs of each group tend to decrease, although no significant difference was found. Two-way repeated measures ANOVA revealed a significant interaction between the timing and observation time points. Post-hoc analysis showed that at each observation time point, BIZs of A-PRF + combined with metronidazole after centrifugation were significantly higher than those before, regardless of the dosage.

Conclusion: The results of this study suggest that supplementing metronidazole into A-PRF + after centrifugation provides better antibacterial efficacy against Fusobacterium nucleatum than before centrifugation.

Clinical relevance: A-PRF + supplemented with metronidazole after centrifugation can exert better antibacterial efficacy against Fusobacterium nucleatum.