EVALUATION OF THE EFFICACY OF AUTOCLAVE STERILIZATION ON DENTAL INSTRUMENTS OVER STORAGE TIME.

Abstract

To microbiologically validate the maintenance of sterility of reusable dental instruments stored under controlled environmental conditions after routine steam sterilization, providing evidence supporting the concept of event-related sterility. This prospective microbiological validation study was conducted using reusable dental instruments from the routine clinical practice of a university dental clinic. After clinical use, the instruments underwent standardized reprocessing, including cleaning, inspection, packaging in surgical-grade paper, steam sterilization in an autoclave, and storage under controlled environmental conditions. Microbiological analyses were performed after 7, 14, 30, 90, and 180 days using Blood Agar, Chocolate Agar, and MacConkey Agar. A total of 53 culture plates were prepared, including 51 experimental plates and two positive control plates to validate the culture media and incubation conditions. No bacterial growth was observed in any experimental culture throughout the storage period, whereas the positive controls showed the expected microbial growth, confirming the reliability of the microbiological methodology. The instruments remained microbiologically sterile for up to 180 days, provided that package integrity and recommended storage conditions were maintained. These findings support the concept of event-related sterility and provide microbiological evidence to guide evidence-based decisions regarding the storage of sterilized dental instruments.