In Vitro Evaluation of Disinfectants on Gutta-Percha Cones: Antimicrobial Efficacy Against Enterococcus faecalis and Candida albicans

Background/Objectives: Periradicular disease is largely microbial in origin. Even gutta-percha (GP) cones manufactured under aseptic conditions can acquire contaminants during handling or storage, undermining otherwise adequate canal preparation. To assess residual antimicrobial activity on GP cones after brief exposure to five endodontic disinfectants: sodium hypochlorite (NaOCl) 1%, 2.5%, 5.25%; chlorhexidine (CHX) 2%; and glutaraldehyde 2% against Enterococcus faecalis and Candida albicans. Methods: Standardized GP cones were dipped for 5–120 s, blotted on neutralizing gauze, and placed on agar inoculated with either organism. Using an agar diffusion approach, inhibition-zone diameters were recorded at 0, 24, and 48 h. Data were summarized using descriptive statistics (means, standard deviations, and 95% confidence intervals) for each disinfectant–dip-time combination. Results: By 24 h, inhibition zones were observed for most disinfectants; for C. albicans, glutaraldehyde 2% showed no measurable effect. At later time points, performance depended on both disinfectant and contact time. For E. faecalis, NaOCl 2.5% and 5.25% yielded the largest zones at 48 h (20–21 mm at 120 s), whereas NaOCl 1% was smaller (10 mm) and glutaraldehyde 2% modest (9 mm). For C. albicans, NaOCl 2.5% and CHX 2% were most effective at 48 h (17–19 mm at 120 s); NaOCl 5.25% was intermediate, NaOCl 1% weak, and glutaraldehyde 2% showed no measurable antifungal effect. Longer immersions (≥45 s) consistently increased inhibition zone diameters. Conclusions: Residual antimicrobial activity on GP cones depends on both the agent and the immersion time. For E. faecalis, higher concentration NaOCl produced the largest zones at short contact time, whereas for C. albicans, CHX 2% and NaOCl 2.5% provided the most reliable carryover. Selecting an appropriate concentration and allowing sufficient dip time may reduce reinfection risk at obturation.