Epigallocatechin Gallate Affects the Development of Matrix-Rich Streptococcus Mutans Biofilm

Objectives: To evaluat the impact of EGCG on Streptococcus mutans biofilm development at 24 and 46 hours using high-resolution confocal laser scanning microscopy.
Methods: S. mutans biofilm initial growth and maturation were evaluated using high resolution confocal laser scanning microscopy. S. mutans biofilm were formed on hydroxyapatite discs and topically exposed twice a day for 1.5 min to the following treatments: NaCl 0.9% (negative control), EGCG 4 mg/ml, and Chlorhexidine 0.12% (positive control). Two experimental regimens were tested to evaluate the effects of EGCG on biofilm development after 24 and 48 h.
Results: EGCG treatment led to the formation of interspaced exopolysaccharide (EPS)-microcolony complexes unevenly distributed on the surface of the hydroxyapatite disc, forming a thinner and less complex biofilm structure with significantly reduced biomass and matrix volume and thickness compared to the NaCl treated group (negative control). Importantly, at 46 h, the biofilm of the EGCG-treatment group failed to form the bacterial-EPS superstructures which is characteristic of the biofilm in the negative control group. Instead, EGCG treatment seems to substantially delay the biofilm development, with 46 h biofilm in the EGCG treatment group representing that of the negative control group at 24 h.
Conclusions: EGCG topical treatments impaired S. mutans biofilm initial growth and maturation, suggesting its potential to be used as a preventative agent against dental caries.