Comparative in vitro Analysis of Microbial Load Reduction on Dental Burs and Endodontic Files Following Different Decontamination Methods

Abstract

Background: Dental instruments when reused poses significant risks of cross-infection. Autoclaving is the gold standard for sterilization, but repeated cycles can degrade the cutting efficiency of burs and files Aims: This study aims to evaluate the sterilization efficacy of a chemically enhanced glutaraldehyde solution using a 4-hour immersion protocol, compared to standard moist heat sterilization and 70% alcohol. Study Design: In vitro Comparative study Place and Duration of Study: Department of Pediatric and Preventive Dentistry, in collaboration with the Department of Microbiology, at Mar Baselios Dental College, between July 2025 and December 2025. Methodology: A total of 120 clinically contaminated instruments (diamond burs, hand K-files, and rotary NiTi files) were divided into four groups (n=30): Group A (70% Isopropyl Alcohol), Group B (4-hr Glutaraldehyde solution), Group C (Autoclave) and Group D (Control). Post-treatment, samples were incubated in Brain Heart Infusion Broth and plated on Brain Heart Infusion (BHI) agar to quantify Colony Forming Units (CFU/mL) Results: Both the Autoclave and 4-hour glutaraldehyde solution groups achieved complete elimination of viable microorganisms. Statistical analysis via ANOVA and Tukey's post-hoc test revealed no significant difference in efficacy between the two methods (P >.05). Conversely, 70% alcohol demonstrated significantly inferior performance, leaving residual contamination on all instrument types (P < .001). Conclusion: The 4-hour glutaraldehyde protocol is an ideal decontamination method, demonstrating microbial reduction levels comparable to the efficacy achieved by autoclaving. This offers a time-efficient and non-corrosive alternative for maintaining the longevity of heat-sensitive dental instruments.