The conventional nonsurgical endodontic treatment/retreatment is the therapy of choice to face primary or post-treatment endodontic infections, respectively. Despite the fact that AP is more prone to develop in teeth with inadequate restorative and endodontic procedures [7], its prevalence continues to increase, with great focus on root canal-treated teeth (post-treatment AP) [8; 9; 10]. Retreatment's main purpose is to reduce the intraradicular microbial load to a level that enables periapical healing [11], removing the maximum of the potentially infected existing root fill. The exposure of the empty and (re)prepared root canal to the irrigating sequence of NaOCl and EDTA is crucial not only to improve disinfection but also to achieve an adequate dentin-sealer interaction for a hermetic reseal [5; 12; 13].  
The use of the chemical irrigants sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) as the recommended protocol remains unquestionable. NaOCl is universally used, with emphasis on tissue dissolution/root canal debridement and antimicrobial/antibiofilm activity [12; 14; 15; 16]. Its efficacy against _Candida_ cells, recognized as refractory to endodontic irrigants and dressings, was confirmed independently of the concentration of tested strains [17]. However, different _Candida_ biofilm phenotypes were reported as tolerant to the standard NaOCl [5]. EDTA, indicated for smear layer removal, significantly inhibited regrowth after NaOCl exposure, although viable _Candida_ cells were still observed. Furthermore, the improved delivery and efficacy of NaOCl activation by different devices [18], in addition to the reduction in unprepared root canal areas through a greater apical enlargement [19], does not necessarily correlate with superior disinfection [20; 21; 22].  
Given the concern about antibiotic resistance, an emphasis on natural products derived from plants, such as essential oils, was simulated, but there are still contradictory results in the dentistry field [23; 24]. A renewed approach and interest in traditional endodontic solvents did not achieve the expected outcomes in what concerns filling removal [25; 26]. Regarding its antibacterial activity, apart from the proven effectiveness of the cytotoxic chloroform [27], there are few reports about the antimicrobial/antibiofilm efficacy of other endodontic solvents [12; 28; 29]. Recently, [PERSON] et al. investigated a novel endodontic retreatment strategy, incorporating non-traditional and safer endodontic solvents, with a different rationale in its application [30; 31; 32; 33; 34]. Preliminary results led to the suggestion of using the binary mixtures methyl ethyl ketone/tetrachloroethylene (MEK/TCE) or methyl ethyl ketone/orange oil (MEK/OOil) as an additional and adjuvant step in filling remnants removal. We hypothesized that the unexpectedly good performance in filling dissolution, obtained through solvents association, could also be reflected in superior disinfection, per se. Therefore, the present work aimed to evaluate the antimicrobial/antibiofilm activity of the solvent mixtures MEK/TCE and MEK/OOil against _C. albicans_ planktonic cells and biofilm. The null hypothesis tested was that the solvent mixtures would not have an additional effect over NaOCl and EDTA treatment.