Flow Cytometry Analysis of Antibacterial Effects of Universal Dentin Bonding Agents on <i>Streptococcus mutans</i>

There is no consensus on the antibacterial activity of dentin bonding systems (DBS). Many study models have been used to evaluate the antimicrobial activity of dental materials. In this study, a novel detection method, flow cytometry, was introduced. It allows for evaluation of the antibacterial activity of DBS, based on assessment of the disruption of the bacterial physical membrane induced by DBS. The aim of the study was to evaluate the antibacterial properties of selected dentin bonding systems against <i>Streptococcus mutans</i>. The highest antibacterial activity against <i>S. mutans</i> was observed for Adhese Universal (99.68% dead cells) and was comparable to that of Prime&amp;Bond Universal, OptiBond Universal, or Clearfil Universal Bond Quick (<i>p</i> &gt; 0.05). The lowest activity of all tested systems was displayed by the multi-mode adhesive, Universal Bond (12.68% dead bacteria cells), followed by the self-etch adhesive, OptiBond FL (15.58% dead bacteria cells). The present study showed that in the case of two-component DBS, the primer exhibited higher antimicrobial activity than the adhesive (or bond) itself.