It might be, if you treat with an over-counter-product that contains a local anesthetic called Benzocaine.
The FDA has advised parents to avoid benzocaine containing products because of reports the medicine can be absorbed from the gums into the bloodstream and cause a life threatening condition caused methemoglobinemia.
That’s a mouthful of a word that means the blood can’t carry oxygen to the tissues of the body. Obviously, that’s a big problem.
The condition is rare, but evidently can occur even if a baby has used it safely before. It can show up within minutes to hours of using benzocaine, and symptoms include shortness of breath, rapid breathing, and blueness of the skin.
Products that contain benzocaine include Anbesol, Oragel, Oragel-Baby, and Hurricane.
Teething sucks, but it’s not dangerous. Don’t make it so by using benzocaine.
BTW, with my kids, we used an iced pacifier. Worked like a charm to quiet them down. (And now that they are in their twenties, I still wonder at times if they need it.)