Description of Streptococcus mutans, Streptococcus sanguinis, and Candida albicans biofilms after exposure to propolis dentifrice by using OpenCFU method

CONTEXT: Dental caries is a major and chronic dental public health problem, which can usually be prevented by regular oral hygiene. The most common oral hygiene practice is brushing teeth with a dentifrice. Propolis has emerged as a promising anti-cariogenic agent, which is considered to be a good oral antiseptic for prevention of caries. Several studies have shown that the use of C has an influence in the growth of oral biofilms. There are several standard methods used to count bacterial colonies, such as crystal violet and CFU Count assays. OpenCFU method is a technique that can be used to calculate biofilm colonies more faster, precisely, and accurately. AIM: To compare several methods for evaluating the number of biofilm colonies formed with exposure to a standard dentifrice and propolis. METHODS AND MATERIALS: Biofilm assays were carried out on 96-well microplates. Reference strains of oral Streptococcus species (S. mutans ATCC 25175(T) and S. sanguinis ATCC 10566(T)) and yeast (Candida albicans ATCC 10231(T)) were inoculated into wells, and 200 µL of standard and propolis dentifrice solution were added to each well and incubated for 18 h at 37 °C. Bacteria and yeast were then sub-cultured on respective media and the colony-forming units (CFU) were counted manually. The other wells were stained by crystal violet and incubated for 15 min, followed by observation using an inverted microscope and evaluated using crystal violet analysis and the OpenCFU automated method. RESULTS: The numbers of CFUs determined for all strains were similar in the standard-dentifrice group and propolis-dentifrice group, and were similar among the three methods: crystal violet staining, manual CFU count, and OpenCFU analysis. CONCLUSION: OpenCFU analysis can be reliably used as a rapid and a more practical method to analyse the growth of oral microorganism biofilms. However, high digital image quality is required to provide an accurate analysis for colony counting.