How to know if I have waited too long to get this cavity filled?

See a dentist ASAP. For examination, x-ray and treatment. It is never too late. The risk in waiting is that it is certain that the cavity will progress and you may loose your tooth. However, implant dentistry is here to stay. Good luck.
Pain, swelling& hole. Your tooth will sort of let you know you waited to long, because it will have a hole, be painful, be swollen or all three! It doesn't necessarily mean you'll lose your tooth, but you may need more complicated treatment to save your it. Seek the advise of a dentist, get an expert to evaluate your oral condition and recommend treatment.

Related Questions

How do I know if I have I waited too long to get a cavity filled?

Signs. Signs of pain/bleeding/swelling indicate that a small problem is now a big one. There are still treatments available. Put the computer down, pick up the phone, and call your dentist...Now! Read more...