Efficacy of Pelargonium sidoides, associated or not to light, on the adhesion and biofilm eradication of Streptococcus mutans

Abstract

Dental demineralization is a result of the tooth dissolution by acids from bacterial metabolism. Streptococcus mutans remains the main bacterial species associated with the development and progression of dental caries. An alternative to combat the accumulation of microorganisms is Photodynamic Inactivation (PDI). Studies have shown that the extract of Pelargonium sidoides can have antibacterial and antiviral effects, because of the gallic acids and other phenolic compounds, as well as its immunomodulatory activity, caused by the combination of phenolic compounds and numerous coumarins. To date, there is no study that has evaluated the action of P. sidoides against cariogenic bacteria, as well as its photodynamic potential. The possible anti-adhesive and anti-biofilm effect, could help in the control of dental biofilms where bacterial adhesion plays a fundamental role. The objective of this study was to evaluate the effect of an oral solution containing P. sidoides, associated or not with light (PDI), on S. mutans samples. This is an in vitro study. The reference strain of the S. mutans species (UA159 ATCC 700610) will be used to obtain standard planktonic suspensions. Tests for capacity for adhesion, minimum biofilm inhibitory concentration (MBIC), and minimum biofilm eradication concentration (MBEC) will be performed. All tests will be executed with and without light exposure, in order to also evaluate the possible photodynamic effect (PDI). A calibration and pilot study will be carried previously to data collection, to determine sample size. Data from each response variable will be analyzed by means of descriptive statistics, according to the group. Then, two factors-analysis of variance will be applied (if the assumptions of normality and homoscedasticity are met). In this case, the Confidence Intervals (95%) will also be calculated for the means, considering the t distribution. The level of significance to be adopted will be of 5%.