In a Type B autoclave, instruments should be bagged:

In a Type B autoclave, it is essential to bag instruments before entering the autoclave for several important reasons. Bagging instruments prior to sterilization serves to protect them from recontamination following the sterilization process. The autoclave utilizes high temperatures and pressurized steam to effectively eliminate microorganisms, and the packaging acts as a barrier that keeps the instruments sterile until they are needed for use.

Additionally, using sterilization pouches or bags helps to maintain the sterility of the instruments for an extended period after the sterilization process is complete. This is especially important in a dental setting where a high standard of infection control is vital to patient safety.

In contrast, bagging instruments after sterilization would render them vulnerable to contamination, making the sterilization process ineffective. Bagging only if instruments are contaminated would not be suitable as all instruments should be sterilized and protected regardless of their apparent contamination status prior to sterilization. Bagging at any time could compromise the integrity of the sterilization process, as the instruments must be handled properly and maintained in a clean environment leading up to the sterilization.