Sustained-release medicament incorporated with cetylpyridinium chloride: An in vitro assessment of Enterococcus faecalis disinfection

Introduction: Effective long-term disinfection requires prolonged release of intracanal medicaments that can effectively penetrate into deeper dentin and eliminate Enterococcus faecalis . The aim of this study was to formulate a sustained-release gel incorporating cetylpyridinium chloride (CPC) and to evaluate its antibacterial activity against E. faecalis in comparison with calcium hydroxide (CH) and 2% chlorhexidine (CHX). Materials and Methods: One hundred and twenty root canal samples were prepared from freshly extracted single-rooted premolars and standardly enlarged up to size 2 Peeso reamer. Root samples were divided into four groups after the successful contamination of the canals with the standard strain of E. faecalis . Medicaments were placed – Group 1: control saline, Group 2: CH paste, Group 3: 2% CHX gel, and Group 4: sustained-release fillers incorporating CPC gel (SRF-CPC). The CPC release profile from the sustained release formulation was assessed using high-performance liquid chromatography. After incubation for 1, 7, and 14 days, dentin shavings were obtained using size 3 and 4 Peeso reamers, which correspond to 200 μm and 400 μm of the root canal space, respectively. Colony-forming units (CFU) were counted and statistically analyzed with a P < 0.05. A one-way analysis of variance (ANOVA), repeated measures ANOVA, and the Bonferroni post hoc test were done. Results: The SRF-CPC gel had the lowest CFU values of all the groups, followed by the CHX and CH groups. At all three observation days (1, 7, and 14 days) and at both the 200 μm and 400 μm dentin depths, the intergroup comparison reveals a highly significant difference ( P < 0.001). Conclusions: The sustained release capability, higher antibacterial activity, and highly desirable handling characteristics of SRF-CPC gel make it the most effective intracanal medication against E. faecalis .