Safe storage times for sterile dental packs

Safe storage times were evaluated for three sterile packaging materials that are commonly used in dentistry. No significant differences were found among packaging materials. Only three packs of 300 produced positive cultures during the 1-year test period. There were no time-related trends. The contamination levels found were within the range that has been reported to occur as a result of inadvertent contamination during unpackaging and transfer of sterile instruments. The findings of this study support the proposal that contamination is event related, not time related; that is, sterile instrument packs remain sterile for at least 1 year unless a specific event causes contamination.