Maybe you can suggest a few things that do work..
Rubber teethers with a gel in them that you can put in the freezer and get cold, but not so cold they burn or feel uncomfortable or could choke them (like ice cubes).
Cut, cool, washed celery stalks at least 4" long, so the baby (or you) can pull them back out of their mouth if the baby starts to stuff them down their throat (which happens). The baby will instinctively pull it back out if it hurts. (Note: carrots and most other vegetables are NOT safe, because the baby can break off little pieces and choke on them, but you can put them in a baby straining mesh thing to keep small pieces from choking them.)
To all parents (especially on sites that are not HN): please do not put anything in your baby's mouth that might hurt them. It's better to listen to them cry then to risk hurting them.
EDIT: removed anbesol/orajel suggestion as unsafe and probably ineffective anyway.