Plant extract incorporated into glass ionomer cement as a photosensitizing agent for antimicrobial photodynamic therapy on Streptococcus mutans

Abstract

BackgroundA plant extract (EB) incorporated into glass ionomer cement (GIG) could be a potential photosensitizer for Antimicrobial PDT (aPDT) against caries-microorganisms, replacing methylene blue (MB), due to the presence of chlorophyll. GIC + EB + aPDT could be an therapeutic alternative to dentin decontamination and sealing, allowing reduction of operative time. ObjectiveEvaluate Dioscorea altissima (EB) incorporated into GIC as a photosensitizer for aPDT against Streptococcus mutans. MethodsGroups (n = 24; ntotal = 192): G1-GIC; G2-GIC + LASER; G3-GIC/EB; G4-GIC/EB + LASER; G5-GIC+MB; G6-GIC + aPDT; G7-GIC/EB + MB; and G8 – GIC/EB+aPDT. In aPDT groups, MB was the photosensitizer. In LASER groups, MB was not used. The irradiation protocol was 660 nm/100 mW/5 J/150 J/cm²/50 s, with a 5-min pre-irradiation time for the MB groups. Antibacterial assays were carried out in 24-well microplates. The wells were completed with one milliliter of a S. mutans in BHI at 1.3 × 108 CFU/mL suspension. After incubation, PDT or laser was performed. After MTT bacteria viability test, the data were submitted to the Kolgomorov-Smirnoff normality test, followed by one-way ANOVA and Tukey's posterior test, α < 0.05. ResultsGroup G6 showed significant inhibition (p < 0.001), followed by groups G4, G5, G7, and G8, which did not show significant differences among them (p > 0.05). Groups G2 and G3 also showed similar results (p > 0.05) and were the least active compared to the others. ConclusionsEB potentiated the antimicrobial action of GIC against S. mutans and laser irradiation over GIC/EB presented better antimicrobials results. The results indicate that EB could be a potential photosensitizer for aPDT.