Antimicrobial and anticaries effects of Malva sylvestris associated or not with fluoride/xylitol under a microcosm biofilm model.

OBJECTIVE

This study evaluated the effects of different combinations of Malva sylvestris on colony-forming unit (CFU) counts and microbiome in a microcosm biofilm, fibroblast cytotoxicity, and reduction of tooth demineralization.

DESIGN

Samples were assigned to nine groups (n = 12): Malva sylvestris (2.5%); M. sylvestris + 5% xylitol; M. sylvestris + fluoride (0.0225%); M. sylvestris + xylitol + fluoride; xylitol; fluoride; M. sylvestris in a commercial product (Malvatricin Plus®); chlorhexidine (0.12%); and PBS. Plant metabolites were extracted by percolation. A microcosm biofilm model was applied, and from the 2nd to the 5th day, samples were treated with the solutions for 1 min. CFU counts were performed for Streptococcus mutans/S. sobrinus, Lactobacillus spp., and Candida albicans. Biofilm samples were analyzed by 16S rRNA gene sequencing (Illumina MiSeq) and QIIME. Cytotoxicity of M. sylvestris (0.08-2%) was assessed on human gingival fibroblasts, and demineralization was quantified by transverse microradiography.

RESULTS

M. sylvestris (2%) showed lower cytotoxicity than chlorhexidine. The combination of M. sylvestris and xylitol reduced S. mutans counts in dentin biofilm by 1 log10/mL compared with PBS (p = 0.03), but not in enamel biofilm. Biofilms treated with M. sylvestris showed microbial communities similar to the negative control. However, the extract combined with fluoride and xylitol significantly reduced enamel demineralization compared with PBS (p < 0.0001), but not dentin demineralization.

CONCLUSION

Malva sylvestris extract combined with fluoride and xylitol showed some antimicrobial and anticaries effects in vitro.