With part still there, it could need looking at one of these days, but if it doesn't seem to bother him after all this time, and his breath remains sweet, then it can most likely wait until you have a car and can plan your own vet outing.
It may never become a problem, but if it's open under there, bacteria could enter. Even if you are there to have something else done/looked at, the vet can tell you what he/she thinks.
Love All Life, Thank You For Posting! :)