## 4 Discussion  
The present study was based on the hypothesis that Propolis exhibits comparable antimicrobial efficacy in comparison to CHX against _E. faecalis_. The outcomes of the present systematic review and meta-analysis showed that the antibacterial efficacy of Propolis as an intracanal medicament against _E. faecalis_ was not comparable or superior to chlorheximide. Therefore, based on these observations, the hypothesis was rejected. Since absolute disinfection of the root canal system is not achievable with instrumentation unaided by intracanal medicament. The use of medicaments is of particular importance to remove remaining microbes and create an environment favorable for per-radicular tissue repair. In endodontic treatment, chlorheximide, iodine potassium iodide, and their combinations with calcium hydroxide have been found effective in reducing the numbers of _E. faecalis_ in the root canal system. However, none of these are considered to ensure complete eradication of _E. faecalis_[20]. _E. faecalis_ is a gram-positive, facultative  
Figure 2: Forest plot showing standard mean difference between Propolis and CHX (control group) treatment in the reduction of _E. Faecalis_ Colony forming units. anaerobe that is present in 22-77% of cases of endodontic failure and is recovered from previously root canal-treated teeth with peri-radicular infection [27; 28]. It can survive as a single organism or as a major part of the endodontic flora even in ecologically demanding conditions [29]. It can penetrate dental tubules and has the remarkable ability to adapt to lethal changes. The capability of the microbe to invade dental tubules and adhere to collagen in the presence of human serum can be considered as a virulence factor responsible for its presence in failed endodontically treated teeth [17; 30; 31]. _E. faecalis_ forms biofilms, which even prolongs its survival by making it resistant to phagocytosis, antibodies, and antimicrobial agents. In the present systematic review, five out of ten included studies [15; 16; 17; 21; 24] concluded that chlorhexidine was more effective than Propolis against _E. faecalis_ as an intracanal medicament. Chlorheximide is a bis-biguanide and effective intracanal medicament in endodontic, with substantivity. It is active against gram-positive as well as gram-negative organisms, particularly _E. faecalis_[24]. [PERSON] et al. [24] evaluated the antibacterial efficacy of Propolis and 2% CHX along with other medicaments, showing maximum microbial inhibition of up to 200-400 micrometers depth, while Propolis exhibited the second highest antibacterial efficacy against _E. faecalis_ among all medicaments. Other studies also reported similar results and mentioned chlorheximide as a more effective intracanal medicament against _E. faecalis_[15; 16; 21]. Interestingly, [PERSON] et al. [32] assessed the minimum inhibitory concentrations of CHX and Propolis along with other irrigants, concluding that Propolis was more effective in lower concentrations (MBC = 0.150 mg/mL compared to 0.512 mg/mL of CHX) against _Candida albicans_, while CHX was more effective in lower concentrations against _E. faecalis_ (0.256 mg/mL compared to 0.6 mg/mL of Propolis). Although the study was not performed on extracted teeth, it reported that chlorheximide is bactericidal to _E. faecalis_ in lower concentrations as compared to Propolis. However, since _E. faecalis_ entraps in dental tubules and the study did not assess bacterial inhibition in extracted teeth, possibly contrasting outcomes could have resulted if extracted teeth were used. In the present study, three studies also concluded that the antibacterial efficacy of Propolis is comparable to CHX against _E. faecalis_[19; 20; 22]. Propolis has been used as an antibacterial agent in traditional medications for a very long time. Its antibacterial efficacy is attributed to its concentration and flavonoid contents. [PERSON] et al.