Exploring the Potential of a Herbal Nanoemulsion as an Antimicrobial Mouthwash

The study aimed to formulate a nanoemulsion, combine it with aqueous extracts of herbal powders, and test its efficiency as caries-preventing mouthwash. Formulation of nanoemulsion using microfluidizer, characterization of nanoemulsion, minimum inhibitory concentration, adherence test, biofilm assay, and artificial mouth assay was carried out. The biofilms of Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus, and a combination of the three cultures were developed and treated with formulations to study the inhibitory effect of the samples. In artificial mouth assay, human tooth samples were used as surfaces to grow the biofilm of S. mutans, and daily, the teeth were treated with the formulations to test their real-time efficiency. The nanoemulsion was characterized using dynamic light scattering and the size of the particles was within the 100-300 nm range. Above 50 °C, the nanoemulsion combined with plant extract lost its emulsified state within 2 h of incubation, while the nanoemulsion was stable. Nanoemulsion with plant extract inhibited the adherence of L. casei (73%) and biofilm of L. casei (66%). In artificial mouth assay, after 10 days of nanoemulsion, nanoemulsion with plant extract showed DIAGNOdent pen values 3.5 and 2 respectively whereas the negative control value was 14.4 indicating caries initiation. The nanoemulsion with plant extract showed anti-adherence and anti-biofilm activity and hence can be used as a potent anticariogenic mouthwash.