In Vitro Evaluation of the Effectiveness of Some Plant Extracts as Antimicrobial Endodontic Irrigants

Introduction: Although Sodium hypochlorite (NaOCl) is currently the most commonly used intracanal irrigant, it sustains a level of dissatisfaction in several aspects. It poses problems such as toxicity, undesirable odor and causes discoloration of clothing. Objectives: The aim was to determine the possibility of using plant extracts such as Salvadora persica (Miswak), Azadirachta indica (Neem) and Hibiscus sabddariffa (Karkada) as alternative root canal irrigants. Methods: Two types of experiments were conducted; the first experiment was based on the 'In Vitro Disc Diffusion Test' and the other on the 'Infected in Vitro Tooth Model'. Prior to experimenting on teeth, the disc diffusion method was used to screen the antimicrobial activity of each irrigant. The diameters of the inhibition zones were taken as an index of the degree of sensitivity. In the infected tooth model 60 single rooted human teeth were impregnated in a suspension of Enterococcus faecalis. Teeth were divided into 4 main groups and the root canals in each group were irrigated with one of the tested irrigants. Microbiological samples were taken before and after irrigation by immersing paper points into the root canal and colony forming units were then counted using standard microbiological techniques. Results: The diameter of inhibition zones recorded in the in vitro disc diffusion test ranged between 8-12 mm. There was no significant difference between the three plant extracts. However significant differences were observed between NaOCl and each of the plant extracts. Results of the in vitro infected tooth model showed no significant differences in mean reduction of CFU between all treatments (P=0.005). Conclusions The disc diffusion test indicated that each of the plant extracts and NaOCl have shown strong inhibitory effects against E.faecalis while the in vitro infected tooth model showed no significant differences in mean reduction of CFU between all treatments.