Electrically Charged Lipid Nanoparticles as Intracanal Antimicrobial Delivery Systems: A Narrative Review of Preclinical Evidence for Biofilm Control

<b>Background:</b> Persistent endodontic infections remain a significant challenge in root canal therapy, primarily due to the complexity of root canal anatomy and the formation of resistant microbial biofilms. Conventional irrigants, including sodium hypochlorite and chlorhexidine, show limited penetration into dentinal tubules and reduced efficacy against mature biofilms, contributing to treatment failure. Electrically charged lipid nanoparticles (ECLNs), such as cationic solid lipid nanoparticles, nanostructured lipid carriers, and liposomes, have emerged as potential adjunctive systems to enhance intracanal antimicrobial delivery. This focused narrative review, informed by a structured literature search, aimed to synthesize and critically evaluate preclinical and exploratory clinical evidence regarding the use of electrically charged lipid nanoparticles for antibiotic delivery and biofilm control in root canal disinfection. <b>Methods:</b> A structured literature search of PubMed, Scopus, and Web of Science (2010-2026) identified 312 records, of which 20 studies met the inclusion criteria and were included in qualitative synthesis. The majority of included studies were in vitro investigations, followed by ex vivo studies using extracted human teeth, with only a limited number of exploratory animal or clinical studies. Overall, the level of evidence was predominantly preclinical. <b>Results:</b> Across studies, ECLNs demonstrated enhanced antimicrobial efficacy compared with free antibiotics or non-charged formulations, with improved biofilm interaction, enhanced penetration into dentinal tubules, and sustained antimicrobial release. However, most investigations relied on mono-species <i>Enterococcus faecalis</i> biofilm models, and substantial heterogeneity in nanoparticle formulation and methodology was observed. Clinical evidence remains scarce. <b>Conclusions:</b> Although these findings about ECLNs suggest a promising experimental adjunct for root canal disinfection, current evidence remains largely preclinical and insufficient to support routine clinical application. Standardized formulations, clinically relevant multispecies biofilm models, and well-designed controlled clinical trials are required to establish safety, efficacy, and translational feasibility.