Primary teeth are vital for a child’s dental and facial development, serving important functions like chewing, speech, and maintaining occlusion until permanent teeth emerge. However, conditions such as dental caries can progress to irreversible pulpitis or pulp necrosis, often accompanied by abscess formation, which are common in pediatric dentistry. In some cases, primary teeth may exhibit signs of both simultaneously. The presence of accessory canals further complicates matters by allowing infective agents to spread into bone marrow spaces and around the developing tooth, undermining the success of endodontic therapy. Inadequate cleaning can result in the persistence of microorganisms and their byproducts, significantly increasing the risk of treatment failure. Thorough removal of pulpal tissues, dentinal debris, and viable microorganisms is vital in endodontic treatment. Complete elimination of microbes is necessary for successful therapy. Inadequate removal can lead to persistent inflammation, hindering healing and compromising treatment effectiveness. Meticulous cleaning and disinfection are essential for optimal outcomes.2 While sufficient instrumentation and irrigation with NaOCl can reduce bacterial counts, but they may not fully eliminate E. faecalis from the root canal.3In cases of post-endodontic therapy pain and infection, E. faecalis is frequently identified,With the prevalence rates reaching up to 90%.This microorganism, characterized as non-fastidious and therapy-resistant, poses challenges in treating infected root canals.Intracanal irrigants play a crucial role in enhancing mechanical debridement by facilitating debris removal, tissue dissolution, and disinfection if canals. The intricate internal anatomy of primary teeth emphasizes the importance of efficient irrigation for thorough cleaning and disinfection.Past efforts to eliminate E. faecalis biofilm with traditional irrigants have been limited. Despite the use of conventional disinfectants and medicaments, achieving and maintaining sterilization of root canals has remained challenging. Intracanal irrigation using a 3.8% w/v solution of SDF, a diluted variant of the SDF used for root canal treatment, has shown promise. Research indicates that 3.8% SDF exhibits antibacterial properties against E. faecalis biofilm and can effectively reduce bacteria as a root canal irrigant. SDF has a high capacity for fluoride release and anti-cariogenic properties, which make it effective for pediatric dentistry. MTAD (a mixture of tetracycline isomer, an acid, and a detergent) has been introduced by Torabinejad and Johnson, is a disinfectant for the root canal system. It consists of a 3% doxycycline aqueous solution, acting as a broad-spectrum antibiotic; 4.25% citric acid, serving as a demineralizing agent; and 0.5% polysorbate 80 detergent (Tween 80). Studies have shown MTAD’s clinical effectiveness and biocompatibility as an endodontic irrigant, equivalent to NaOCl.Sodium hypochlorite (NaOCl), commonly used in root canal treatment, effectively dissolves organic substances but has drawbacks. Its advantages include affordability and organic dissolution capability. However, drawbacks of NaOCl include cytotoxicity, foul odor, clothing bleaching, metal corrosion, incomplete bacterial eradication, smear layer retention, dentin property alteration, and reduced antimicrobial effectiveness over time due to exposure to oxygen, room temperature, and light. So, this study will be aimed to assess and compare the efficacy of 3.8% SDF, MTAD, and 1 % NaOCl as irrigants against Enterococcus faecalis in root canals of pulpectomized primary teeth through an in vivo investigation.