My dentist, for example, sterlizes instruments before using them on me, but they are spread out on a tray in a room with no special air filters AFAIK.
How long can those instruments be considered sterile while sitting out like that?
Same question about when I open a package of gauze that says it’s sterile (“guaranteed if unopened”).
Same question applies to surgical instruments. Is there anything special about the treatment of the air in an operating room that preserves a sterile environment? Or is it controlled just by making sure every object in the room is strerile coming in?