Influence of surface topography on anti-biofilm activity of triterpenoid compound

Abstract

OBJECTIVES: The purpose of this study was to investigate the effect of three-dimensional surface topography on the Streptococcus mutans UA159 biofilm formation in the presence of an antibacterial triterpenoid compound. METHODS: Two types of composite resin disks, flat surface and surface with grooves, were used throughout this experiment. The biofilm-eradicating properties of ursolic acid (UA) and chlorhexidine (CHX) were evaluated according to various times (0, 15, 30, 45, 60 minutes) and sub-minimum biofilm inhibitory concentrations (0, 80, 160, 320, 640 μg/ml of UA and 0, 15.625, 31.25, 62.5, 125 μg/ml of CHX). To understand the role of surface topography on Streptococcus mutans biofilm formation, scanning electron microscopy (SEM) and crystal violet assay were used for qualitative and quantitative assessments, respectively. RESULTS: After biofilm formation, treatment with antimicrobial agent led to no significant differences in the anti-biofilm activity of UA or CHX between the flat and groove disks. When the disks were treated with antimicrobial before biofilm formation, there was more biofilm formation on groove composite resin disk compared to flat composite resin disk, while the control group without antimicrobial agent resulted in similar amount of biofilm formation for flat and groove disks. CONCLUSIONS: This study suggests that antimicrobial can be used as an effective therapeutic regimen on pre-existing biofilm regardless of surface topography. However, when antimicrobial is administered as a preventive regimen, it will have limited effect in inhibiting biofilm formation on caries-prone surfaces of tooth. Therefore, surface topography plays a significant role in the biofilm formation of Streptococcus mutans UA159 in the presence of antimicrobial agent.