Hi Anna, I am not a Dr but a registered dental hygienist. If the dentist told you that you don't need antibiotics yet, then most likely you don't (not clear from your posts if you're in the US or not) In the US, antibiotics aren't routinely given for a small tooth infection (only for an abscess that is on the end of the tooth root-visible through x-Ray OR if your jaw is swollen, sore, and you have a draining "pimple" on the gum). As long as none of that is happening, you should be fine until the extraction. Just be sure, if your ortho and dentist require it, take an antibiotic "premedication" before it is pulled. Usually taken approx. one hour before appointment. The Dr's will decide what kind of antibiotic and in what amount.
Interestingly, many dental Dr's and professionals (I learned this at a US dental convention last year) believe that joint replacement "premed" is not warranted anymore (via American Heart Ass.). I did notice, although this is to be strongly considered, the Drs were still reluctant to actually recommend this. Perhaps in the future, with further research, none of us will have to take it. In the meantime, call your ortho Dr or his/her nurse and see what they want you to take before your next dental appt.
Good luck, you should be fine. I understand that a joint infection from dental problems is actually pretty rare. I take continuing education classes for my license on a regular basis. It is still better to error on the side of caution, of course!
Lu