Calcium Hydroxide-based Sustained-release Formulations in Endodontics: A Narrative Review

Abstract Calcium hydroxide has long been used as a primary intracanal medicament in endodontic therapy due to its strong antimicrobial properties and high biocompatibility. Despite these advantages, its clinical performance is limited by rapid degradation, short-lived alkalinity, and restricted ion diffusion. To address these limitations, sustained-release formulations have been developed to prolong its therapeutic activity within the root canal. This narrative review explores the evolution and current advancements in such delivery systems, including microspheres, nanotechnology-based carriers, and polymer-supported formulations. A comprehensive literature search of PubMed and Scopus databases identified in vitro and in vivo studies evaluating the physicochemical behavior and antimicrobial efficacy of these systems. The findings indicate that advanced sustained-release formulations, particularly those using nanoencapsulation or biodegradable polymer matrices, provide more uniform calcium ion release, maintain elevated pH levels for longer durations, improve dentinal tubule penetration, and show enhanced activity against resistant pathogens such as Enterococcus faecalis. These innovations represent promising progress in improving endodontic disinfection. However, further well-designed clinical trials are essential to validate their long-term safety, effectiveness, and clinical applicability.