Microbial Profile of Persistent Endodontic Infections and Emerging Antimicrobial Strategies

This is the authors' abstract. We don't add key points for this paper.

Persistent endodontic infections remain a clinically important cause of post-treatment apical periodontitis and root canal treatment failure.These infections are commonly driven by stress-adapted microorganisms that survive chemomechanical preparation, intracanal medication, obturation, and host immune pressure within protected anatomical niches.Despite advances in microbial detection and antimicrobial technologies, evidence remains fragmented regarding the microbial signatures that predict treatment failure and the clinical effectiveness of newer adjunctive disinfection strategies.This review aimed to examine the microbial profile of persistent endodontic infections and to evaluate conventional and emerging antimicrobial approaches to improve root canal disinfection.Relevant literature on endodontic microbiology, biofilm biology, antimicrobial resistance, conventional irrigants, intracanal medicaments, nanoparticles, photodynamic therapy (PDT), laser-assisted disinfection, ozone, plasma, antimicrobial peptides, and bacteriophage-based therapy was synthesized narratively.The reviewed evidence identified polymicrobial biofilm formation, dentinal tubule invasion, and antimicrobial tolerance as major contributors to microbial persistence, with Enterococcus faecalis (E.faecalis), Actinomyces, anaerobic bacteria, and Candida species (spp.)frequently implicated.Conventional disinfection strategies remain central to clinical management, although their effectiveness is limited against mature biofilms.Photodynamic therapy and laser-assisted disinfection showed potential benefits in experimental and selected clinical studies, whereas other emerging approaches were supported primarily by laboratory evidence.Heterogeneous protocols, limited high-quality clinical trials, and insufficient long-term safety and healing outcomes limit definitive conclusions regarding their clinical effectiveness and suitability for routine practice.