None of this means that every single patient’s procedure now is pain-free, even if everything is done correctly. The novocaine injections are themselves pretty uncomfortable, and can be terrifying for patients who fear needles. Some patients with additional complications, such as severe nerve inflammation, won’t fully respond to the available anesthetics, Sigurdsson noted. And some evidence suggests that people with intense anxiety about their procedure are more difficult to anesthetize, maybe because their fight-or-flight response or some other neurochemical reaction inhibits the anesthetic’s effectiveness. But, Sigurdsson promised me, the majority of his patients are “pleasantly surprised.”

If decades of dental students have been taught to fully numb their root-canal patients instead of diving right into their pulp, then why does the procedure’s reputation persevere? It might be because, for most people, root canals are mercifully rare. Many people who will need more than one in their lifetime go decades between procedures, unaware that their next one won’t be so bad. For people who’ve never had a root canal, they may remember their parents complaining about a particularly bad one.

Or millions of people may have been misled simply by growing up in the 1990s. According to Google Ngram, which tracks the popularity of words in books and newspapers over time, the phrase was particularly omnipresent in media during that decade. Joking about root canals does fit in with the what’s-the-deal-with-airplane-food comedy of the era; an episode of Seinfeld even features the specter of Jerry’s future root canal and the procedure’s seriousness as a reason he fights with Elaine. But as better-trained dentists enter the field and more people have uncomfortable but uneventful root canals, the same Google data show that the procedure’s ability to strike fear in our hearts, at least metaphorically, may be waning.