Antimicrobial potential of Pelargonium sidoides and an isolated coumarin, associated or not with light and ultrasound, against microorganisms in root infections

Abstract

Endodontic treatment consists of debridement and cleaning of the root canal system to remove remaining tissue and eliminate microbial biofilm. Even with antimicrobial instruments and irrigants, the complete elimination of microorganisms is still a challenge for endodontics. In this context, the search for natural compounds with low toxicity, antimicrobial efficacy and the use of supporting techniques, such as photodynamic inactivation and sonodynamic inactivation, is of great importance. The aim of this study will be to provide an overview of the effectiveness of photodynamic protocols for microbial elimination and endodontic treatment (Study I), to investigate the antimicrobial profile of Pelargonium sidoides (PS) and 7-hydroxy-5,6-dimethoxycoumarin (UK), one of the coumarins present in PS, alone and when associated with light, ultrasound and both (Study II) and define the protocols with the greatest potential for clinical application to be evaluated in an intracanal biofilm model (Study III). For Study I, a search for already published systematic reviews will be carried out to evaluate the effectiveness of photodynamic inactivation in endodontics, and the use of eligibility criteria for inclusion of the reviews. After extracting data from the included reviews, it's expected to define a protocol with greater potential for clinical application according to existing literature data. In study II, the antimicrobial profile of PS and UK will be determined, alone and when associated with light, ultrasound and both, by means of Inhibitory Concentration and Minimum Bactericidal assays against E. faecalis, F. nucleatum and C. albicans. Then, three concentrations of PS and UK will be selected for testing against biofilms of the same species formed on the bottom of a plate. In Study III, the results of previous studies will be integrated in order to define protocols to be evaluated in an intracanal biofilm model, comparatively and in relation to curcumin and irrigants used in endodontics, through an ex vivo study in bovine teeth with confocal fluorescence microscopy analysis. The results will be analyzed using descriptive statistics and, depending on the study, one-way or two-way fixed ANOVA and confidence intervals for means (±=0.05). If the results are promising, this study could design a potential clinical treatment protocol that will lead to an effective adjuvant alternative in endodontic therapy.