Ask a surgeon why by law they are required to wear those blue surgical masks while in any surgical procedure where open wounds are present go ahead ask one. Hint it’s not for the surgeons well being. There is a reason every person in a surgical procedure must be masked,same for dental procedures ask why.
1). you can’t use your hand or sleeve to cover your cough or sneeze when scrubbed in a case. 2) see number one - it keeps snot/ gum/ gross contamination out of the surgical field.
I don’t recall my dentist ever using a mask until AIDS came along.
So Sawbones does not spit (spittle) into the open wound.
My recollection as a tech in research was that wearing surgical masks helped prevent getting bacterial contaminants into the areas of the little animals I was working on. Many times they were immune compromised critters, so that we had wanted to have some idea of when they got sick, if it was really what we were doing, instead of happenstance. Always tried to get one less variable out of the way, though, yes, it was there. We wanted to minimize what bacteria the little creatures encountered. Viruses, not so much.
Surgical mask specifications required them to stop bacteria (big bugs and germs) from infecting open surgical wounds. They were only worn one time, for a short time and then disposed of in biohazards waste containers.
They are not designed to stop viruses.
So they don’t slobber into the open cavity, I would assume
Medical personal are masked during procedures where the tissues of a patient are opened in any way, to help (not 100% foolproof) prevent the medical personal from breathing any contaminant into the open tissue(s) of the patient.
Think of it like the mask wearer taking the position that they might be the problem.
In Covid terms ONLY those who know or suspect they are infected are the equivalent of the medical personnel who wear masks in a medical procedure. There is no definitive studies that prove the asymptomatic are major communicators of Covid to others.
And, if masking would be truly exercised most importantly it would be the opposite of where they want everyone to be masked. It would NOT be for those times we are randomly passing each other out in the public spaces.
Respiratory viruses are spread under these parameters - sufficient viral load, close contact, enclosed spaces, over some period of time.
Masking would be better put to use where about 60% of contact cases are made - in the home between family members (close contact, enclosed space, some period of time). HAD THAT been done, instead of where masking was mandated, the U.S. case count may have been only 40% of what it was.