- Fusobacteriumnucleatum (F. nucleatum) has been reported as a trigger for endodontic infections. This infection can be treated by cleaning and shaping procedures using EDTA irrigation and NaOCl. Both of these materials have some drawbacks. Lerak fruit (Sapindusrarak DC) inhibited the growth of gramnegative bacteria such as F. nucleatum. This study aimed to evaluate the potential of Sapindusrarak DC in inhibiting the development and formation of F. biomass concerning the porosity of the root canal walls. This study used F. nucleatum isolate ATCC 23726 and ethanol extract of Lerak fruit. Using SEM, the assessment was carried out by evaluating the biomass index, adhesion test, and root canal wall porosity. The results showed the results showed Lerak fruit extract with concentrations

Keywords : Adhesion, Fusobacteriumnucleatum, Irigant solution, Porosity, Sapindus Rarak DC.