Subject of many dental procedures, due to pain-free dentistry,
I have become focused on the needle that delivers the novocaine.
Anesthetics preceded antiseptics, which were not established until after
1854 when John Snow showed that cholera was carried by contaminated water, and
after 1860, when Louis Pasteur pointed out that micro-organisms were responsible for infections.
See also in The book of science:
Readings on wikipedia: