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

ABSTRACT 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.

Antibacterial, antibiofilm, and cytotoxic activities and chemical compositions of Peruvian propolis in an in vitro oral biofilm.

Background: Natural products with antibacterial potential have begun to be tested on biofilm models, bringing us closer to understanding the response generated by the complex microbial ecosystems of the oral cavity. The objective of this study was to evaluate the antibacterial, antibiofilm, and cytotoxic activities and chemical compositions of Peruvian propolis in an in vitro biofilm of Streptococcus gordonii and Fusobacterium nucleatum. Methods: The experimental work involved a consecutive, in vitro, longitudinal, and double-blinded study design. Propolis samples were collected from 13 different regions of the Peruvian Andes. The disk diffusion method was used for the antimicrobial susceptibility test. The cytotoxic effect of propolis on human gingival fibroblasts was determined by cell viability method using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay, and the effect of propolis on the biofilm was evaluated by confocal microscopy and polymerase chain reaction (PCR). Results: The 0.78 mg/mL and 1.563 mg/mL concentrations of the methanolic fraction of the chloroform residue of Oxapampa propolis showed effects on biofilm thickness and the copy numbers of the srtA gene of S. gordonii and the radD gene of F. nucleatum at 48 and 120 hours, and chromatography (UV, λ 280 nm) identified rhamnocitrin, isorhamnetin, apigenin, kaempferol, diosmetin, acacetin, glycerol, and chrysoeriol. Conclusions: Of the 13 propolis evaluated, it was found that only the methanolic fraction of Oxapampa propolis showed antibacterial and antibiofilm effects without causing damage to human gingival fibroblasts. Likewise, when evaluating the chemical composition of this fraction, eight flavonoids were identified.

Evaluación "in vitro" de la resistencia a la penetración bacteriana usando dos técnicas de obturación y dos selladores endodónticos frente a una cepa de Enterococcus faecalis / "In vitro" Assessment of bacterial penetration resistance using two compaction techniques and two endodontic sealers against Enterococcus faecalis strain

Evaluar ôin vitroõ la resistencia a la penetración bacteriana utilizando dos diferentes técnicas de obturación, compactación vertical y lateral con dos selladores endodónticos, uno a base de polidimetilsiloxano y el otro a base de hidróxido de calcio y resina epóxica frente a una cepa de Enterococcus faecalis ATCC 29212. Materiales y Métodos: Ochenta y cuatro dientes uniradiculares se dividieron de manera aleatoria en 4 grupos (n=20) y dos grupos de control (n= 4). El grupo I se obturó con la técnica de compactación lateral y sellador Sealer 26, el grupo II se obturó con la técnica de compactación vertical y sellador Sealer 26, el grupo III se obturó con la técnica de compactación lateral y sellador Roeko Seal y el grupo IV se obturó con la técnica de compactación vertical y sellador Roeko Seal. Se utilizó Enterococcus faecalis como marcador bacteriano y la penetración bacteriana se evaluó cada hora durante las primeras 96 horas, posterior a esto cada 12 horas durante 15 días. Resultados: Se utilizó la prueba de Kruskal Wallis (p=0.696) para comparar los 4 grupos y la prueba de la U de Mann Whitney para comparar pares de grupos, al comparar las técnicas de compactación según el sellador endodóntico no se encontró diferencias estadísticamente significativas en ambos materiales (Grupo I y II p=1.000, Grupo III y IV p=0.296). Al comparar los selladores endodónticos según las técnicas de compactación no se encontró diferencias estadísticamente significativas (Grupo I y III p=0.328, Grupo II y IV p=1.00). Sin embargo se registró un tiempo máximo de 115 horas para el grupo III y un tiempo mínimo de 18:21 horas para el grupo I. Conclusiones: No se encontró diferencias estadísticamente significativas en cuanto a la resistencia a la penetración bacteriana entre los selladores Roeko Seal y Sealer 26 en combinación con las técnicas de compactación lateral y vertical frente a una cepa de Enterococcus faecalis...

Objectives: The purpose of the study was to assess ôin vitroõ bacterial penetration resistance using two different obturation techniques, vertical compaction and lateral compaction with two endodontic sealers, one based on polydimethylsiloxane and the other based on calcium hydroxide and epoxy resin against Enterococcus faecalis strain ATCC 29212. Methods: Eighty-four uniradicular teeth were randomly divided into 4 groups (n = 20) and two control groups (n = 4). Group I was obturated with lateral compaction technique and Sealer 26, group II with vertical compaction technique and Sealer 26, group III with lateral compaction technique and Roeko Seal and group IV with vertical compaction technique and Roeko Seal. Enterococcus faecalis was used as a bacterial marker and bacterial penetration was assessed monitoring the specimens every hour for the first 96 hours and after this every 12 hours over a period of 15 days. Results: Kruskal Wallis test (p = 0.696) was used to compare the four test groups and the Mann Whitney U test was used to compare pairs of groups. Nevertheless, no statistically significant differences were found comparing compaction techniques as endodontic sealers (Group I and II p=1.000, group III and IV p=0.296). No statistically significant differences were found when comparing endodontic sealers as compaction techniques (Group I and III p=0.328, group II and IV p=1.000). Although there was a maximum of 115 hours for group III and a minimum time of 18:21 hours for group I. Conclusions: No significant differences were found regarding bacterial penetration resistance between Roeko Seal and Sealer 26 in combination with lateral and vertical compaction techniques against a strain of Enterococcus faecalis...