Antibacterial and Antiadhesion Effects of Psidium guajava Fractions on a Multispecies Biofilm Associated with Periodontitis

Objective: To assess the antibacterial activity of Psidium guajava fractions and their effects on adhesion of a multispecies biofilm consisting of Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis in vitro. Material and Methods: Guava leaves were obtained from the mountains of northern Peru, where they grow wild and free of pesticides. The antimicrobial activity of 25 mg/mL petroleum ether, 25 mg/mL dichloromethane and 25 mg/mL methanol fractions of P. guajava was evaluated by measuring inhibition halos, as well as the effect on the adhesion of multispecies biofilms at 4, 7 and 10 days of growth by measuring the optical density. In addition, antimicrobial susceptibility was compared using the Kruskal-Wallis test and its multiple comparison tests, and differences in mean biofilm adhesion between each fraction were assessed by repeated measures analysis and the Tukey multiple comparison test. Results: The rank-based Kruskal-Wallis test highlighted differences in the effects of the fractions on the zone of inhibition for each oral bacterium, including S. gordonii(p=0.000), F. nucleatum (p=0.000), and P. gingivalis (p=0.000), the Tukey test showed that the group treated with 0.12% chlorhexidine exhibited the least amount of adhesion, followed by the group treated with the 1.56 mg/mL methanol fraction. Conclusion: The methanol fraction of P. guajava had an antibacterial effect on S. gordonii and P. gingivalis, and the 1.56 mg/mL methanol fraction decreased biofilm adhesion

Antibacterial Effect of Hypochlorous Acid on Bacteria Associated with the Formation of Periodontal Biofilms: An in vitro Pilot Study

Objective: To evaluate the antibacterial effect of electrolytically generated hypochlorous acid on Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis. Material and Methods: In this in vitro experiment, the effect of hypochlorous acid (HOCl) on the strains S. gordonii, F. nucleatum, and P. gingivalis was evaluated using 4% sodium hypochlorite, 0.12% chlorhexidine, and distilled water as controls. The four groups were placed on each plate, and each group was replicated five times. The agar diffusion method by zones measurement was used. The data were processed with SPSS using the Kruskal-Wallis test and multiple comparison tests. Results: Hypochlorous acid showed an average inhibition halo of 9.28 mm on S. gordonii. As expected with distilled water, no zone of inhibition was noted for any of the bacteria, nor were zones of inhibition observed with HOCl for F. nucleatum and P. gingivalis. Conclusion: Hypochlorous acid showed antimicrobial properties against only S. gordonii and was less effective than 4% sodium hypochlorite and 0.12% chlorhexidine, although no significant differences were found between the latter